Bosch Appliances Water Heater ESVVT User Manual

MODEL GWH 2700 ES NG and GWH 2700 ES LP -

INDOOR MODEL

Temperature Modulated with Electronic Ignition

Suitable for heating potable water only

Not approved for space heating purposes

(Intended for variable flow applications)

GWH 2700 ES NG - Natural Gas

GWH 2700 ES LP - Liquefied Petroleum (LP) Gas

Warning: If the information in this manual is not

followed exactly, a fire or explosion may result

causing property damage, personal injury or death.

Do not store or use gasoline or other flammable

vapor and liquids in the vicinity of this or any other

appliance.

What to do if you smell gas

• Close gas valve. Open windows.

• Do not try to light any appliance.

• Do not touch any electrical switch; do not use any

phone in your building.

• If you cannot reach your gas supplier, call the fire

department.

Improper installation, adjustment, alteration,

service or maintenance can cause injury or

property damage. Refer to this manual. For

assistance or additional information consult a

qualified installer, service agency or the gas

supplier.

• Immediately call your gas supplier from a neighbor’s

phone. Follow the gas supplier’s instructions

• Installation and service must be performed by a

qualified installer, service agency or the gas supplier.

In the Commonwealth of Massachusetts this

product must be installed by a licensed plumber or

gas fitter.

Upon completion of the installation, these

instructions should be handed to the user of the

appliance for future reference.

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Warning

Warning: The appliance should be

located in an area where leakage of the

heater or connections will not result in

damage to the area adjacent to the

appliance or to lower floors of the

structure. When such locations cannot

be avoided, it is recommended that a

suitable drain pan, adequately drained,

be installed under the appliance. The

pan must not restrict combustion air

flow.

For your safety

Do not store or use gasoline or other flammable,

combustible or corrosive vapors and liquids in the

vicinity of this or any other appliance.

Warning: Carefully plan where you

install the heater. Correct combustion

air supply and flue pipe installation are

very important. If a gas appliance is not

installed correctly, fatal accidents can

result, such as carbon monoxide

poisoning or fire.

Warning: The maximum inlet gas

pressure must not exceed the value

specified by the manufacturer and that

the minimum value listed is for the

purposes of input adjustment.

Warning: Exhaust gas must be vented

to outside using stainless steel vent

material suitable for category III vent

systems and temperatures up to 480°F.

Vent piping must be sealed gas-tight to

prevent possibility of flue gas spillage,

carbon monoxide emissions and risk of

fire, resulting in severe personal injury

or death. Approved vent terminators

must be used when penetrating to the

outside.

Warning: If a water heater is installed in

a closed water supply system, such as

one having a backflow preventer in the

cold water supply line, means shall be

provided to control thermal expansion.

Contact the water supplier or local

plumbing inspector on how to control

this situation.

Warning: Place the heater in a location

where water leaks will do NO DAMAGE

to adjacent areas or lower floors.

Warning: Keeping appliance area clear

and free from combustible materials,

gasoline and other flammable vapors

and liquids.

Warning: Field wiring connections and

electrical grounding must comply with

local codes, or in the absence of local

codes, with the latest edition of the

National Electric Code, ANSI/NFPA 70,

or in Canada, all electrical wiring must

comply with the local codes and the

Canadian Electrical Code, CSA C22.1

Part 1.

Warning: Do not obstruct the flow of

combustion and ventilation air.

Warning: Precautions must be taken

prior to manually operating the relief

valve to avoid contact with hot water

coming out of the relief valve and to

prevent water damage.

Warning: Shock hazard: line voltage is

present. Before servicing the water

heater, unplug power supply cord from

outlet. Failure to do so could result in

severe personal injury or death.

Caution: Label all wires prior to

disconnection when servicing controls.

Wiring errors can use improper and

dangerous operation.

Verify proper operation after servicing.

Warning: The heater must be

disconnected from the gas supply

piping system during any pressure

testing of that system at test pressures

equal to or more than 0.5 psig.

Warning: In order for the freeze

prevention kit to provide adequate

protection,120V AC must always be

supplied to the water heater.

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Appliance details

Warning: The anti freeze kit is

designed to provide protection for the

water heater down to approximately 5°F

for short term conditions only. It will not

protect the appliance in areas where the

temperature is routinely expected to be

below freezing.

2.1 Features

Parts

• Key Pad interface control

• High power pre-mix compact burner with low NOx

emissions

B The anti freeze kit will not protect

plumbing outside the appliance from

freezing. Precautions should be taken.

• Modulating Gas Valve with constant gas:air ratio

control

B Always drain the water heater if it will be

exposed to long term freezing

conditions. See Section 6.2 Winterizing

for seasonal use.

• Modulating water valve for improved comfort and

temperature control.

High quality materials for long working life

• Copper heat exchanger

• High efficiency Ceramat Burner

Warning: If a relief valve discharges

periodically, this may be due to thermal

expansion in a closed water supply

system. Contact the water supplier or

local plumbing inspector on how to

correct this situation. Do not plug the

relief valve.

• Compact space saver: mounts on a wall with a

supplied bracket.

Features

• Real-time diagnostics for troubleshooting/informational

purposes

• LCD Display with backlight

• On/Off and Temperature control switches

• Reset button

FCC:

This device complies with Part 15 of the FCC rules.

Operation is subject to the following two conditions: (1)

This device may not cause harmful interference, and (2)

this device must accept any interference received,

including interference that may cause undesired

operation.

• Program button (Selectable temperature default)

• Failure codes for easy diagnostics and repair

• Easily removable one-piece cover

• Built in freeze prevention.

Note: The freeze prevention is designed to provide

protection for the water heater down to approximately 5°F

for short term conditions only. It will not protect the

appliance in areas where the temperature is routinely

expected to be below freezing.

D A N G E R

- The freeze prevention will not protect plumbing outside

the appliance from freezing. Precautions should be taken.

Accessories (Bosch part #)

• Optional wireless remote control accessory to operate

with the appliance (TSTAT2)

HOT

• Cascading kit (TLINK)

• Outdoor kit (AQOK)

BURN

• Gas conversion kit (8719002176)

• Vertical vent kit (ESVVT)

• Horizontal vent kit (AQ3ES¹⁾)

Water temperature over 125°F can

cause severe burns instantly or

death from scalds.

• Stainless steel bird screen (L2594)

(fits into a 3” PCV fitting - Intake vent).

Children, disabled and elderly are

at highest risk of being scalded.

BOSCH is constantly improving its

products, therefore specifications are

subject to change without prior notice.

See instruction manual before

setting temperature at water

heater.

Feel water before bathing or

showering.

1) AQ3 vent kit is compatible with this appliance but

requires the purchase of an additional 12" piece of

straight pipe to meet minimum vent length requirements.

The aluminum flex piping included with this kit is not per-

missible for use with this appliance.

6720608643-16.1AL

Fig. 1

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Appliance details

Dimensions

2.2 Specifications (Technical data)

Approved in US/Canada

• Depth (in): 11¼” (286 mm)

• Width (in): 17 ⁷/₈” (452 mm)

• Height (in): 30½” (775 mm)

• Weight: 67 pounds (30,5 kg).

Capacity

Maximum flow rate: 7.15 GPM (27 l/min) at a 45°F

(25°C) rise.

Gas types

Maximum output

Natural Gas.

LP Gas.

160,500 Btu/h (47.0 kW)

Maximum input

Converting the gas type can only be done by a certified

gas technician with a calibrated CO₂analyzer.

199,000 Btu/h (58.3 kW)

Call Bosch Water Heating through Bosch

thermotechnology corp. for conversion instructions.

Efficiency in %

Thermal efficiency > 82%

Voltage

Min. Input

120 V AC (60 Hz) nominal

19,900 Btu/h (5.8 kW)

Amperage

Temperature Control

Idle - 40 mA

Operation - ≤ 2.5 A

Selection range: 100°F (38°C) - 140°F (60°C)

Default temperature: 122°F (50°C)

Stability: +/- 2°F (+/- 1°C)

Noise

45 - 65 db (A)

Gas Requirement

Safety devices

Gas connection (inches) - ¾”

• Flame failure device (ionization flame rod sensor)

• Pressure relief valve (supplied with heater)

• Over heat prevention (temperature limiter)

• Inlet temperature sensor

Inlet gas pressure under operation (with a high hot

water flow rate)*

• Propane: 8” - 13” water column

• Natural Gas: 3.5” - 10.5” water column.

• Outlet temperature sensor

* To measure gas pressure, see Measuring Gas

Pressure, chapter 3.12.

• Backflow temperature sensor.

Water protection

Water

IP X4 (protection against water drops)

• Hot water connection (inches) - ¾”

• Cold water connection (inches) - ¾”

If appliance is installed at elevations above

2000ft, refer to section 3.3.6 Fan speed

adjustment.

• Water valve material: Polymer (PPS) (Polypropylene

Sulfid)

• Minimum water flow: 0.65 gallon/minute (2,5 l/m).

Note: Activation varies with inlet water temperatures

from 0.65 - 1.6 gallon/minute.

• Minimum recommended water pressure: 30 PSI

(2.07 bar)

•

Minimum recommended well pressure: 40 PSI (2.75

bar), see chapter 3.9.

• Connections:

– Bottom of heater

Combustion

• NOx ≤ 40 Ng/J (Nanograms of NOx (calculated as NO ) per

Joule of heat output).

• CO ≤ 250 ppm (measured)

• CO₂level set from factory, see chapter 6.4.

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Appliance details

To remove front cover

2.3 Unpacking the heater

B Loosen the two Philips head screws located on

bottom rear of cover (see Fig. 3).

Before installing the unit, be certain you have the

correct heater for your type of Gas: Propane or

Natural Gas. Identification labels are found on the

shipping box, and on the rating plate which is located on

the right side panel of the cover.

Fig. 3 Loosen the two screws

B Lift front cover panel upward and remove.

Fig. 2 Rating plate

Serial number

Type of gas

The box includes:

• GWH 2700 ES

• Pressure relief valve (150 psi / 200,000 Btu rating)

• Bracket for wall hanging the heater

• Exhaust vent adaptor (with 4 screws and gasket

provided)

• Combustion air inlet adaptor (with 3 screws and gas-

ket provided)

• Installation manual (manual can be downloaded at

www.boschhotwater.com)

• Product registration card

• Energy Guide label.

Fig. 4 Removing the front cover

To remove combustion cover (service only)

Please complete and return the enclosed product

registration card.

B Open the four clips and remove the combustion

cover see Fig. 5.

The GWH 2700 ES is not approved or designed

for:

• Manufactured (mobile) homes, boats or any mobile

installation (modular homes are acceptable for

installation)

• Use above 8000 ft A.S.L. altitude (see page 18)

• Outdoor installation without installation of Outdoor

kit (AQOK)

• Space heating purposes

• Preheated inlet water supply.

Fig. 5 Remove the combustion cover

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Appliance details

10. Failure to install heater correctly may lead to

unsafe operation and void the warranty.

2.4 General rules to follow for safe

operation

1. You must follow these instructions when you install

your heater. In the United States: The installation must

conform with local codes or, in the absence of local

codes, the National Fuel Gas Code ANSI Z223.1/

NFPA 54.

In Canada: The Installation must conform with CGA

B149.(1,2) INSTALLATION CODES and /or local

installation codes.

B 2. Carefully plan where you install the heater. Correct

combustion air supply and vent pipe installation are

very important. If not installed correctly, fatal

accidents can occur, such as carbon monoxide

poisoning or fire.

B 3. When the unit is installed indoors and ROOM

SEALED (twin pipe) it is permitted to be located in

bathrooms, bedrooms and occupied rooms that are

normally kept closed. See chapter 3.3 (page 9). If the

unit will be installed indoors and use indoor

combustion air, the place where you install the heater

must have enough ventilation. The National Fuel

Gas Code does not allow UNSEALED gas fired

water heater installations in bathrooms,

bedrooms or any occupied rooms normally

kept closed. See chapter 3.5

page 20).

(page 21) and 3.4

(

B 4. You must vent your heater. See chapter 3.3 on

VENTING.

B 5. The appliance and its gas connection must be leak

tested before placing the appliance in operation.

The appliance must be isolated from the gas supply

piping system by closing its individual manual gas

shutoff valve (not supplied with heater) during any

pressure testing at pressures in excess of ½ Psig (3.5

kPa).

B 6. Keep water heater area clear and free from

combustibles and flammable liquids. Do not locate

the heater over any material which might burn.

B 7. Correct gas pressure is critical for the proper

operation of this heater. Gas piping must be sized to

provide the required pressure at the maximum output

of the heater, while all the other gas appliances are in

operation. Check with your local gas supplier, and

see the section on connecting the gas supply. See

Section 3.8, page 17.

B 8. Should overheating occur or the gas supply fail to

shut off, turn off the gas supply at the manual gas shut

off valve, on the gas line. Note: manual gas shutoff

valve is not supplied with the heater but must be field

installed.

B 9. Do not use this appliance if any part has been

underwater. Immediately call a qualified service

technician to inspect the appliance and to replace any

part of the control system and any gas control which

has been underwater.

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Appliance details

2.5 Dimensions and Minimum installation clearances

4¹" 5 ¼"

6 ½"

2^{1 16}"

11 ¼"

5 ¼"

reset

6720608158-04.2AL

Fig. 6 Dimensions

On/Off button

Reset button

Program key

Model GWH 2700 ES

TOP (A)

12”

1”

Power ON or stand-by LED

LCD display

Up button

FRONT (B)

BACK

Down button

0”

SIDES

1”

FLOOR (C)

12”

Table 1 Minimum clearances

Fig. 7 Minimum clearances

Note: For servicing access, a 2ft clearance to front

cover is recommended.

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Installation instructions

3.1 Tools required for installation

Warning: Approved terminators must

be used for inlet and exhaust vent sys-

tems to prevent rain from entering the

appliance. Failure to do so may result in

damage to the appliance. This failure is

not covered under the manufacturer’s

warranty.

• Philips head screwdriver

• Flat head screwdriver

• Adjustable wrench

• Level

• Thermometer

• Standard plumbing tools

• Manometer

Caution: The vent system must be

installed by a qualified installer in

accordance with these instructions. If

• Drill

improperly installed,

hazardous

• Pipe wrench

condition such as explosion or carbon

monoxide poisoning could result.

Bosch Water Heating will not be

responsible for improperly installed

appliances.

• Adjustable pliers

• Pipe fitting tools

• Hacksaw

• Hole saw.

Warning: In areas where outside

temperatures routinely come close to

freezing, sealed combustion operation

is required. Use separate terminations

for combustion and vent, which must be

installed on the same wall or roof

surface, however never facing the

direction of prevailing winds. Failure to

do so may result in heat exchanger

freezing up and bursting. This failure is

not covered under the manufacturer's

warranty.

3.2 Introduction

Please follow these instructions. Failure to follow

instructions may result in:

B Damage or injury.

B Improper operation.

B Loss of warranty.

If you are unable to perform the tasks required to install

this heater properly, please contact a locally licensed

plumber or gas technician.

Common installation practice is to deter-

mine the venting/intake system layout and

penetration and then work back to the

heater.

3.3.1 Vent material

Establish vent clearances that comply with the vent

manufacturer's specifications. In all cases, follow local

codes. See Table 2.

3.3 Venting

Diam.

Material

Warning: Do not reduce the vent

(exhaust and combustion) pipe sizes

and do not common vent with any other

vented appliance or stove.

Exhaust

Vent

3 or 4 inches Sealed single wall stainless steel

(AL29-4C)

Intake

Vent

3 or 4 inches Sealed PVC or any other rigid pipe

Warning: Failure to vent the exhaust

gases to the outside with sealed

stainless steel vent pipe (AL29-4C)

may result in dangerous flue gases

filling the structure in which it is

installed.

Table 2 Venting Specifications

Warning: Do not mix vent pipe or

from

joining methods

manufacturers.

different

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Installation instructions

Horizontal venting systems only:

3.3.2 Venting Specifications

An optional stainless concentric vent/air intake termina-

tion can be used to provide only one penetration point

through the exterior wall (see Fig. 8, 9 & 10). The con-

centric vent/air intake kit can be ordered from your local

wholesaler. (Part# ESHCK). Note: Vent piping and

terminal used with concentric vent/air intake kit

must be from the same vent pipe manufacturer.

The appliance can also be installed with separate

air intake and exhaust piping (see Fig. 15 ).

Install appliance as close to point of vent termination as

possible. The exhaust piping must vent directly to the

outside of the structure.

Horizontal sections of vent must pitch upward towards

termination ¼" for every foot of horizontal length, to

prevent the pooling of condensate, and be supported at

4 foot intervals with overhead hangers.

Exception: horizontal run between last elbow and

termination must pitch down to termination 1/4" per

foot. Note: For horizontal terminations, venting must

terminate once it penetrates to the outside of the

structure. There must be no sections of vent pipe

exposed to the outdoors other than the termination.

Note: Listed thimbles or collars are necessary where

venting passes through wall and ceiling partitions. If the

vent system passes through combustible areas where

the vent clearance requirements cannot be maintained,

it is permissible to chase straight sections of sea led 3

inch single wall vent through 4 inch (or greater) T ype-B

vent. The distance to combustibles using this chase

technique is 1 inch 1). Note: Type-B vent must never be

used as the actual exhaust vent system for the

appliance, as it is not gas tight and illegal for use with

this appliance. This will create a serious health hazard

and void the warranty.

6720608782-09.1Av

Fig. 8 Concentric kit part # ESHCK

3”

VENTING

Z flex

Protech

Heat Fab

3 or 4"

90° elbow

2SVEEWCF0390

FSELB9003

9314

3”

Horizontal

Terminal

2SVSTB03

FSTB3

FSRC3

9390 TEE

5300CI

6720608782-10.1Av

3” Vertical

Terminal

2SVSRCF03

Fig. 9 Concentric kit vent assembly

Table 3 Terminator Part Numbers

Fittings or Piping

Equivalent

feet

12"

45 degree elbow

90 degree elbow

pipe per foot

1.25

2.5

0.38

0.76

0.30

Min. 3 Feet

3” stainless steel pipe

Table 4 Friction Loss Equivalent in piping and fittings

For specific questions concerning vent material, speci-

fications, usage or installation, please contact the vent

manufacturer directly.

Company

Z-flex

Contact info

www.z-flex.com

800-654-5600

ProTech Industries

Heat-Fab

www.protechinfo.com

800-766-3473

www.heatfab.com

800-772-0739

6720608782-11.1Av

Fig. 10 Concentric kit installation

Table 5 Vent manufacturers

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Installation instructions

# of 90° elbows

Condensate drain requirements

Air intake or

Exhaust

system

An external condensate drain (not supplied with the

heater) must be installed under the following

conditions:

N/A*

• All vertical terminating vent installations.

• Horizontal terminating vent installations where the

total linear vent length is greater than 10 feet (3.1 m).

• Vent installations where any section of the exhaust

vent pipe passes through an unconditionedspace.

# of 45°

N/A**

elbows

Twin pipe termination clearances

The minimum clearance between exhaust vent and

combustion air inlet terminations for twin pipe

penetration is 3 feet.

N/A** N/A**

Maximum allowable straight pipe length (ft)

Minimum combustion air and exhaust pipe

length

Table 6 Maximum allowable straight pipe length

The minimum exhaust pipe length is 3 feet (1m) of

straight vent pipe. The minimum combustion air pipe

length is one 90° elbow.

Not allowed. At least one 90º elbow required.

Not allowed. Minimum of 3 feet (1m) of straight pipe required.

Maximum combustion air and exhaust pipe

length

The following table (Table 6) displays the maximum

allowable straight pipe lengths for combustion air and

exhaust piping with consideration to the number of

elbows used.

Note: 90° elbows used for terminations

should not be counted in the exhaust and

combustion air piping.

Step 1: Total the number of 90° elbows and 45°

elbows used on the exhaust piping.

Step 2: Use this value in the table to determine the

maximum straight exhaust pipe length

allowed.

Step 3: Total the number of 90° elbows and 45°

elbows used on the combustion air piping.

Step 4: Use this value in the table to determine the

maximum straight combustion air pipe length

allowed.

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Installation instructions

Required direct vent terminal clearances (twin pipe / concentric penetration)

6720608836-23.1Av

Fig. 11

Canadian installations

U.S. installations

Clearance above grade, veranda, porch, deck or balcony

Clearance to window or door that may be opened

Clearance to permanently closed window

12 in.

36 in.

12 in.

Vertical clearance to ventilated soffit located above the vent

terminator within a horizontal distance of 2 feet (61cm) from the

center line of the terminator

Clearance to unventilated soffit

Clearance to outside corner

Clearance to inside corner

Clearance to each side of center line extended above meter/

regulator assembly

36 in. within a height 15 feet above

meter/ regulator assembly

Clearance to service regulator vent outlet

36 in.

Clearance to non-mechanical air supply inlet to building or the

combustion air inlet to any other application

12 in.

Clearance to mechanical air supply inlet

72 in.

36 in. above if within 10 feet

horizontally

Clearance above paved sidewalk or paved driveway located on

public property

84 in. ³⁾

12 in. ⁴⁾

Clearance under veranda, porch deck or balcony

Table 7

In accordance with the current CSA B149.1 Natural Gas and Propane Installation Code

In accordance with the current ANSI Z223.1 / NFPA 54 National Fuel Gas Code

A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single family dwellings and serves both dwellings.

Permitted only if veranda, porch, deck or balcony is fully open on a minimum of two sides beneath the floor.

For clearances not specified in ANSI Z223.1 / NFPA 54 or CSA-B149.1, one of the following shall be indicated:

a) A minimum clearance value determined by testing in accordance with section 2.20, or;

b) A reference to the following footnote:

“Clearance in accordance with local installation codes and the requirements of the gas supplier.”

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Installation instructions

Required other than direct vent terminal clearances (single pipe penetration)

6720608836-23.1Av

Fig. 12

Canadian installations

U.S. installations

Clearance above grade, veranda, porch, deck or balcony

Clearance to window or door that may be opened

12 in.

36 in.

12 in.

4 feet below or to side of opening;

1 foot above opening

Clearance to permanently closed window

Vertical clearance to ventilated soffit located above the vent

terminator within a horizontal distance of 2 feet (61cm) from the

center line of the terminator

Clearance to unventilated soffit

Clearance to outside corner

Clearance to inside corner

Clearance to each side of center line extended above meter/

regulator assembly

36 in. within a height 15 feet above

meter/ regulator assembly

Clearance to service regulator vent outlet

36 in.

Clearance to non-mechanical air supply inlet to building or the

combustion air inlet to any other application

4 feet below or to side of opening;

1 foot above opening

Clearance to mechanical air supply inlet

72 in.

36 in. above if within 10 feet

horizontally

Clearance above paved sidewalk or paved driveway located on

public property

84 in. ³⁾

12 in. ⁴⁾

84 in.

Clearance under veranda, porch deck or balcony

Table 8

In accordance with the current CSA B149.1 Natural Gas and Propane Installation Code

In accordance with the current ANSI Z223.1 / NFPA 54 National Fuel Gas Code

A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single family dwellings and serves both dwellings.

Permitted only if veranda, porch, deck or balcony is fully open on a minimum of two sides beneath the floor.

For clearances not specified in ANSI Z223.1 / NFPA 54 or CSA-B149.1, one of the following shall be indicated:

a) A minimum clearance value determined by testing in accordance with section 2.20, or;

b) A reference to the following footnote:

“Clearance in accordance with local installation codes and the requirements of the gas supplier.”

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Installation instructions

3.3.3 Venting configuration examples

Below are approved examples of horizontal

venting installations.

HORIZONTAL RUN

1/4" PER FOOT

DOWN TO

TERMINATOR.

CONDENSATE

DRAIN

6720608542-05.2AL

Fig. 15 Horizontal twin pipe penetration

6720608542-02.2AL

Below are approved examples of vertical venting

installations.

Fig. 13 Horizontal side wall venting installation (single

pipe penetration)*

Important:

* Warning: for non-freezing climates only!

Note: Pitch horizontal runs down toward the heater,

1/4" per foot.

Important:

Note: Pitch horizontal runs down toward the heater,

except horizontal run between last elbow and termina-

tion which must slope down to termination 1/4" per

foot.

RAIN CAP

10' MIN.

2' MIN.

STORM COLLAR

3' MIN.

FLASHING

Note: For horizontal terminations, venting must

terminate once it penetrates to the outside of the

structure. There must be no sections of vent pipe

exposed to the outdoors.

FIRESTOP SUPPORT

4" MIN.

AIR SPACE

FIRESTOP SUPPORT

12"

HOSE

CLAMP

Min. 3 Feet

3” stainless steel pipe

ELBOW

CONDENSATE

DRAIN

APPLIANCE

6720608158-91.2Av

Fig. 16 Vertical venting installation (single pipe pene-

tration)*

6720608782-11.1Av

Fig. 14 Horizontal venting installation (concentric

penetration)

* Warning: for non-freezing climates only!

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Installation instructions

3.3.4 Vent connections

B Attach the flue gas exhaust accessory (8 705 504

162) to the top of the unit (position 1) using the 4

screws and gasket provided. Fully insert stainless

steel vent pipe 1.5” minimum into the accessory and

tighten the clamp (position 2).

NOTE: Vent pipe must be completely ver-

tical when inserting or gasket inside ex-

haust accessory can become displaced.

Exhaust accessory can be removed with

vent pipe attached to check gasket posi-

tion.

Fig. 17 Vertical venting installation (twin pipe penetra-

tion)

RAIN CAP

10' MIN.

STORM COLLAR

FLASHING

2' MIN.

SILICONE SEAL

3' MIN.

Fig. 19

B Attach the combustion air inlet accessory (8 705

504 116) to the top of the unit (position 3) using the

3 screws and gasket provided, and install air intake

pipe over the accessory. NOTE: The appliance has

the option to mount the combustion air inlet acces-

sory on the top right or on the top left side of the

heater. The combustion air inlet that is not used must

be kept sealed.

CHIMNEY

MAY BE INSULATED

IF NECESSARY

HORIZONTAL RUN

1/4" RISE/FT

HANGER STRAP

MORTAR

ELBOW

HOSE

CLAMP

CONDENSATE

DRAIN

Fig. 20

B Ensure that exhaust vent pipe is fully inserted in collar

to enable proper connection.

APPLIANCE

Exhaust venting must be 3" or 4" sealed

single wall stainless steel (AL29-4C) vent

pipe.

6720608158-14.2AL

Fig. 18 Vertical venting installation - Masonry Chim-

ney (combustion air piping not shown)

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Installation instructions

3.3.5 Condensate drain installation

Note: Do not install condensate drain in areas where it

may freeze.

1. Install condensate drain as close to heater as possi-

ble.

2. Use 3/8" ID high temperature silicone tube to con-

nect to condensate drain port. Do not use copper pip-

ing for any portion of the condensate drain.

3. Form a condensate trap by means of a 3" loop par-

tially filled with water.

4. To increase the tube length, connect to end of the

high temperature silicone tubing with vinyl tubing, PVC

or CPVC pipe. Do not reduce the internal diameter at

any point.

5. Dispose of condensate according to local codes.

RAIN CAP

10' MIN.

2' MIN.

STORM COLLAR

3' MIN.

FLASHING

FIRESTOP SUPPORT

4" MIN.

AIR SPACE

ELBOW

CONDENSATE

DRAIN TEE

DRAIN TRAP

TO DRAIN - DISPOSE

OF CONDENSATE

ACCORDING TO

LOCAL CODES

APPLIANCE

6720608782-04.2Av

Fig. 21 Condensate drain installation (combustion air

piping not shown)

3" Venting

Z-flex

ProTech Heat Fab

90°

Condensate

Drain Tee

2SVEVWCF03 FST3 &

FSDF3

93PPLSTEE

Horizontal

Condensate

Drain

2SVEDWCF03 FSHDT3

9321

Condensate

Drain Tube

2SVEDTK24

N/A

7000TUBE

Table 9 Approved Condensate Drain Part Numbers

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Installation instructions

3.3.6 Fan speed adjustment

Example

Exhaust

IMPORTANT! Installation adjustment:

• 7 - 3' straight sections

After installing the water heater, the fan speed values for

minimum power (P2) and maximum power (P1) may

need adjustment due to variations in altitude and vent

pipe length.

• 1 - 1' straight section = Total straight pipe length 22’

• 2 - 90° elbow.

Intake

Failure to make necessary adjustments to fan speed

values may result in improper operation of the

appliance.

• 5 - 3' straight sections = Total straight pipe length 15’

• 1 - 90° elbows.

First calculate the total equivalent vent length. Use this

value to determine the appropriate fan speed values,

found in Table 12 and make any necessary

adjustments. After changing fan speed values proceed

to Section 6.4 to confirm CO₂values are within

specified ranges.

Example

Exhaust

Straight section length

(feet)

22 x 1 =

Total equivalent vent length calculation

90° elbows (qty)

45° elbows (qty)

Total:

1 x 2.5 =

2.5

B Determine the total length of all straight sections of

vent pipe and enter in table 10, line 1.

0 x 1.25 =

B Count the number of 90° elbows used and enter that

value in line 2. (Do not count terminals and first elbow

used on intake and exhaust).

24.5

B Count the number of 45° elbows used and enter that

value in line 3.

Intake

B Repeat steps 1 through 3 for air intake pipe and enter

those values in the intake section of table 10.

Straight section length

(feet)

15 x 1 =

B Add line 4 from Exhaust to line 4 of Intake and enter

result in line 5.

This is the total equivalent vent length.

90° elbows (qty)

45° elbows (qty)

Total:

1 x 2.5 =

0 x 1.25 =

Exhaust

39.5

Straight section length

(feet)

__ x 1 = ____

__ x 2.5 = ____

__ x 1.25 = ____

Total equivalent vent length =

Table 11 Determining vent length combination exam-

ple

90° elbows (qty)

Note: Do not count terminals and first elbow used on

intake and exhaust.

45° elbows (qty)

Total:

____

Total equivalent length must not to

exceed 57ft.

Intake

Straight section length

90° elbows (qty)

__ x 1 = ____

__ x 2.5 = ____

__ x 1.25 = ____

Total: ____

NOTE: If using concentric terminal include

exhaust pipe length that is part of the con-

centric terminal.

45° elbows (qty)

Total equivalent vent length = ____

Table 10 Determining vent length combination (see

example in Table 11)

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Installation instructions

Natural Gas

Maximum

power fan power fan speed power fan speed

Liquid propane

Maximum

Altitude

(above sea

level)

Total

equivalent

vent length¹⁾

Minimum

speed (P2)

(P1)

5.5 - 32 ft

33 - 57 ft

5.5 - 32 ft

33 - 57 ft

5.5 - 32 ft

33 - 57 ft

0 - 2000 ft

(0 - 610 m)

modification required

For operation at elevations

above 2,000 ft (610 m) the

equipment ratings shall be

reduced at the rate of 4% for

each 1,000 ft (305 m) above sea

level

48*

49*

50*

47*

48*

49*

2000 - 4500 ft

(610 - 1372 m)

4500 - 8000 ft

(1372 - 2439 m)

* Above 2000 ft, CO₂levels must be checked with a combustion gas analyzer, see section 6.4 for instructions.

Table 12 Fan speed adjustment

Full equivalent length (inlet + outlet piping + fittings)

Adjusting minimum power fan speed (P2)

Adjusting maximum power fan speed (P1)

To select fan speed:

B Press ON/OFF button into OFF.

B Press and hold "Program" button

ON/OFF button to turn appliance ON.

and press

B Press and hold "Program" button

ON/OFF button to turn appliance ON.

and press

Fig. 22

Fig. 23

B As soon as '188' is displayed, release "Program"

button

B As soon as '188' is displayed, release "Program" but-

ton

, and the display should read P2.

, and the display reads P2.

B Press

or to choose the fan speed suitable

B Press the minus button

B Press “Program” button

The current setting will appear on the display.

to display P1.

with your installation, see Table 12.

to enter P1 adjustment.

B Press and hold ( 5 sec.) “Program” button

until

the display flashes, then the selected value is memo-

rized.

B Press or to choose the fan speed suitable

with your installation, see Table 12.

B Press and hold ( 5 sec.) “Program” button

until

Do not set P2 to greater then 9.

the display flashes, then the selected value is memo-

rized.

Proceed directly to Section 6.4 to confirm

CO₂values are within range.

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Installation instructions

Attention residents of the Commonwealth of

Massachusetts:

signage installed in accordance with the provisions of

248 CMR 5.08(2)(a)1 through 4.

In the Commonwealth of Massachusetts the following

regulation went into effect on 12/30/2005:

(b) EXEMPTIONS: The following equipment is exempt

from 248 CMR 5.08(2)(a)1 through 4:

(a) For all side wall horizontally vented gas fueled

equipment installed in every dwelling, building or

structure used in whole or in part for residential

purposes, including those owned or operated by the

Commonwealth and where the side wall exhaust vent

termination is less than seven (7) feet above finished

grade in the area of the venting, including but not limited

to decks and porches, the following requirements shall

be satisfied:

1. The equipment listed in Chapter 10 entitled

"Equipment Not Required To Be Vented" in the most

current edition of NFPA 54 as adopted by the Board;

and

2. Product approved side wall horizontally vented gas

fueled equipment installed in a room or structure

separate from the dwelling, building or structure used in

whole or in part for residential purposes.

EQUIPMENT VENTING SYSTEM REQUIRED. When

the manufacturer of Product Approved side wall

horizontally mounted gas equipment provides a venting

system design or venting system components with the

equipment, the instructions provided by the

manufacturer for the installation of the equipment and

the venting shall include:

1. INSTALLATION OF CARBON MONOXIDE

DETECTORS. At the time of installation of the side wall

horizontal vented gas fueled equipment, the installing

plumber or gasfitter shall observe that a hard wired

carbon monoxide detector with an alarm and battery

back-up is installed on the floor level where the gas

equipment is to be installed. In addition, the installing

plumber or gasfitter shall observe that a battery

operated or hard wired carbon monoxide detector with

an alarm is installed on each additional level of the

dwelling, building or structure served by the side wall

horizontal vented gas fueled equipment. It shall be the

responsibility of the property owner to secure the

services of qualified licensed professionals for the

installation of hard wired carbon monoxide detectors.

1. Detailed instructions for the installation of the venting

system or the venting system components: and

2. A complete parts list for the venting system design or

venting system.

(d)MANUFACTURER REQUIREMENTS

GAS

EQUIPMENT VENTING SYSTEM NOT PROVIDED.

When the manufacturer of a product approved side wall

horizontally vented gas fueled equipment does not

provide the parts for the venting of flue gases, but

identifies "special venting systems," the following

requirements shall be satisfied by the manufacturer:

a. In the event that the side wall horizontally vented gas

fueled equipment is installed in a crawl space or an at

tic, the hard wired carbon monoxide detector with alarm

and battery back-up may be installed on the next

adjacent floor level.

1. The referenced "special venting system" instructions

shall be included with the appliance or equipment

installation instructions; and

b. In the event that the requirements of this subdivision

can not be met at the time of completion of installation,

the owner shall have a period of thirty (30) days to

comply with the above requirements; provided,

however, that during said thirty (30) day period, a

battery operated carbon monoxide detector with an

alarm shall be installed.

2. The "special venting systems" shall be product

approved by the Board, and the instructions for that

system shall include a parts list and detailed installation

instructions.

(e) A copy of all installation instructions for all products

approved side wall horizontally vented gas fueled

equipment, all venting instructions, all parts lists for

venting instructions, and/or all venting design

instructions shall remain with the appliance or

equipment at the completion of the installation.

2. APPROVED CARBON MONOXIDE DETECTORS.

Each carbon monoxide detector as required in

accordance with the above provisions shall comply with

NFPA 720 and be ANSI/UL 2034 listed and IAS

certified.

3. SIGNAGE. A metal or plastic identification plate shall

be permanently mounted to the exterior of the building

at a minimum height of eight (8) feet above grade

directly in line with the exhaust vent terminal for the

horizontally vented gas fueled heating appliance or

equipment. The sign shall read, in print size no less than

one half (1/2) inch in size, "GAS VENT DIRECTLY

BELOW. KEEP CLEAR OF ALL OBSTRUCTIONS".

4. INSPECTION. The state or local gas inspector of the

side wall horizontally vented gas fueled equipment shall

not approve the installation unless, upon inspection, the

inspector observes carbon monoxide detectors and

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Installation instructions

below for providing adequate combustion air for the

water heater as well as any other appliances that may

consume air in the space. Always follow local codes if

they are more stringent.

3.4 Combustion air requirements

Warning: In areas where outside

temperatures routinely come close to

freezing, sealed combustion operation

is required. Use twin pipe or concentric

terminations for combustion air and

exhaust, which must be installed on the

same wall or roof surface, however

never facing the direction of prevailing

winds. Failure to do so may result in

heat exchanger freezing up and

bursting. This failure is not covered

under the manufacturer's warranty.

When all requirements are followed, the unit will

operate properly and safely. However, there may still be

a risk of freezing due to negative draft if the other

combustion appliances in the building are not supplied

with sufficient combustion air. A wood stove or furnace

can pull its combustion air from the heater's vent pipe,

allowing the cold incoming air to freeze the cold water

in the heat exchanger. Supplying more combustion air

for all combustion appliances is the solution. A HVAC

specialist should be consulted to design solutions for

providing more combustion air. Observe the following

guidelines:

Installations in structures that have been tightly

constructed (air infiltration rate of 0.40 ACH or less)

must be provided with combustion air per the National

Fuel Gas Code. Consult a HVAC specialist if your air

infiltration rate is questionable.

Warning: When installed in an

environment where corrosive chemicals

or dirty air (e.g. hair salons, car washes)

are present the twin pipe system is

required.

The space must have two permanent openings, one

commencing within 12 inches of the top and one

commencing within 12 inches of the bottom of the

enclosure.

Twin pipe and Concentric pipe

The water heater is designed as a sealed combustion

appliance. It is recommended that the combustion air

be provided from the outside by a dedicated pipe (twin

pipe) or by connecting to the concentric vent kit (see

Fig. 8, 9 & 10). The combustion air pipe may be PVC

or any other rigid sealed 3" or 4" pipe. Horizontal

sections of the combustion air pipe must pitch down

towards termination 1/4" per foot to prevent rain water

from entering the appliance. When using the twin pipe

method, combustion air inlet, whether terminating

vertically or horizontally, must be located in such a

manner as to provide a minimum 3 foot clearance

from the exhaust vent terminator. See Fig. 11 and

Fig. 12 Letter I, page 12.

Each opening must have a minimum free area of one

square inch per:

• 1000 Btu/hr if all air is taken from inside the building

• 2000 Btu/hr if all air is taken from the outside by

horizontal ducts

• 4000 Btu/hr if all air is taken from the outside by

direct openings or vertical ducts.

Or the space must be provided with one permanent

opening or duct that is within 12 inches of the ceiling of

the enclosure.

For the maximum length of the combustion air

inlet pipe, see table 6.

This opening must have a minimum free area of one

square inch per:

• 3000 Btu/hr if all air is taken from the outside by a

direct opening or vertical duct.

Warning: Vent terminations must

prevent rain from entering the

combustion air and exhaust vent piping.

Louvers, grills and screens have a blocking effect. If the

effective free area is not known, increase the sizes of

your openings by 300% if your louvers are wood and by

43% if your louvers are metal. Refer to the National Fuel

Gas Code for complete information.

Single pipe

Note: This appliance requires 9950 cubic feet of

available combustion air, or a minimum of 1243

square feet of space with an 8 foot ceiling to

operate. If the large amount of air space, which

equates to about half of most average sized

homes, is not available, the appliance must pull

air from outside (see twin pipe system above).

Although it is permissible to draw combustion air from

inside the structure, it is not the manufacturer’s

recommended installation method. Always install a 3

inch elbow on the top of the combustion air inlet

adaptor to prevent foreign objects from falling into the

unit.

If a single pipe installation is utilized, follow guidelines

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Installation instructions

3.5 Proper location for installing your

heater

3.7 Mounting installation

Warning: before starting

installation

Carefully select the location of the water heater. For

your safety and for proper heater operation, you must

provide combustion air to the heater and a proper

exhaust vent system.

B Check that there are no loose or

the

damaged

appliance

parts

inside

Follow the guidelines below:

B Confirm the gas type of the heater

matches the gas supply you will be

connecting the heater, see Fig. 2,

page 6.

B 1. Locate the heater where venting, gas and

plumbing connections are feasible and convenient.

B 2. The hot water lines should be kept short and

insulated to save energy. Centrally locating the water

heater is recommended to keep hot water

distribution times even throughout the structure.

Front cover should be removed (see

instructions on page 6) in order to inspect

components visually.

Warning: The water in this water

heater is cold and always remains cold

except for the times the burner is on. In

the event of power outage in

conjunction with freezing temperatures,

it is recommended that the heater be

drained.

Warning: Do not install this appliance

on a carpeted wall. The heater must be

mounted on a wall using appropriate

anchoring materials.

See chapter 6.2, page 32 “Winterizing”

for draining instructions.

Warning: In areas where outside

temperature is routinely below 32°F and

the heater is to be installed on the inside

of an exterior wall, a minimum 2" air gap

or rigid insulation between the heater

back and the wall is recommended.

Warning:

Flammable

materials,

gasoline, pressurized containers, or any

other items or articles that are potential

fire hazards must NOT be placed on or

adjacent to the heater. The appliance

area must be kept free of all

combustible materials, gasoline and

other flammable vapors and liquids.

If wall is sheathed with plaster or drywall, it is recom-

mended that two support boards, either 1”x4” or 1/2"

(minimum) plywood first be attached across a pair of

studs, see Fig. 24.

B Secure the wall mounting bracket provided with the

heater to the wall surface. The heater must be kept

level on the wall surface (see Fig. 25).

3.6 Heater placement and clearances

The water heater is approved for installation on a

combustible wall (see chapter 3.7 Mounting

installation) provided the floor covering below

the heater is noncombustible. For installations in an

alcove or closet, maintain the minimum clearances to

combustible and non-combustible materials. See Fig. 7

and Table 1 on page 8.

B Hang the appliance on the bracket, see Fig. 26.

Clearances from any exhaust vent pipe are dependent

upon the clearance requirements of the stainless steel

vent pipe manufacturer. Single wall stainless steel

(AL29-4C) vent pipe (vent type rated for Category III

appliances) must be used when exhaust venting this

appliance. See chapter 3.3 (page 9) Venting.

Studs 16"

(406mm) on

center

Fig. 24 Distance between support boards

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Installation instructions

3.8 Gas piping & connections

Before connecting the gas supply, check the rating

plate on the right side of the heater to be sure that the

heater is rated for the same gas to which it will be

connected.

In the United States: The installation must conform with

local codes or, in the absence of local codes, the

National Fuel Gas Code ANSI Z223.1/NFPA 54.

In Canada: The Installation must conform to CSA B149

INSTALLATION CODES and/or local installation

codes.

Warning: DO NOT connect to an

unregulated or high pressure propane

line or to a high pressure commercial

natural gas line.

6720608158-64.1AL

Warning: The heater must be isolated

from the gas supply piping system

during any pressure testing of that

system at test pressures equal to or

more than 0.5 psig. If overpressure has

occurred, such as through improper

testing of the gas lines or malfunction of

the supply system, the gas valve must

be checked for safe operation.

Fig. 25 Leveling the mounting bracket on the studs

GAS CONNECTIONS

B Install a manual gas shut off valve on the gas supply

line within easy reach of the appliance.

B Install a union when connecting gas supply.

B The minimum internal diameter required for

any appliance connector is ¾”.

B Undersized flexible appliance connectors not

permitted.

B National Fuel Gas Code requires that a sediment

trap (drip leg) be installed on gas appliances not so

equipped. The drip leg must be accessible and not

subject to freezing conditions. Install in accordance

with the recommendations of the serving gas sup-

plier, see Fig. 27.

6720608158-05.1AL

Fig. 26 Mounting the heater

Warning: Appliance must be installed

vertically.

Gas supply

Minimum

3”

Cap

Fig. 27 Gas connection (drip leg)

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Installation instructions

Once connections are made, check for gas leaks at all

joints. Apply some gas leak detection solution to all gas

fittings. Bubbles are a sign of a leak. A combustible gas

detector may also be used to detect for leaks.

Danger: If you have a leak, shut off the

gas. Tighten appropriate fittings to stop

leak. Turn the gas on and check again

with a gas leak detection solution.

Never test for gas leaks using a match

or flame.

GAS LINE SIZING

The gas supply piping for a single heater should be

sized for a maximum draw of 199,000 BTUH. Measure

the length of gas supply line and use the tables in

Fig. 29, page 24 or the gas line manufacturer’s sizing

tables to determine the pipe diameter necessary to

accommodate the 199,000 BTU demand of the heater.

If there are more gas appliances on the line, size the gas

line according to the total maximum amount of BTU

input rating for all appliances.

Note: Undersizing the gas line may result in diminished

hot water flow rate and temperature. See chapter 3.12,

page 27 for the procedure to confirm gas pressure.

Proper gas pressure must be confirmed at time of

installation.

Inlet gas particle screen

(included)

Gas piping

Fig. 28

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Installation instructions

FOR NATURAL GAS

Maximum Capacity of pipe in Cubic Feet of Gas per Hour for Gas Pressure of 0.5 Psig or less and a Pressure drop

of 0.3” in Water Column (0.75mbar).(Based on a 0.60 Specific Gravity Gas) Btu numbers given in thousands.

Follow boxed numbers for piping just one GWH 2700 ES (example: ¾” B.I. Natural Gas pipe for 10 ft (3.0m).

will handle 278,000 btu’s (81.5 kWh). For multiple appliances combine the total maximum btu input load and

then refer to applicable chart below.

Nominal

Iron

Length of Black iron Pipe , Feet

Pipe

Size,

Internal

Diameter

inches inches

100

125

150

175 200

1/4

3/8

1/2

0.364

0.493

0.622

132

3/4

0.824

1.049

1.380

1.610

2.067

278

520

190

350

152

285

590

890

130

245

500

760

115 105

215 195 180

440 400 370

670 610 560

170

350

530

160

320

490

930

150

305

460

870

130

275

410

780

120

250

380

710

110 100

225 210

350 320

650 610

1 1/4

1 1/2

1050

1600

3050

730

1100

2100 1650 1450

1270 1150 1050 990

Length of Flexible Corrugated Stainless Steel Tubing (CSST), Feet

Tube

size,

inches

EHD*

1/2

3/4

18 EHD 82

23 EHD 161 116

30 EHD 330 231 188

162

325

144

292

131

267

* EHD = Equivalent Hydraulic Diameter. The greater the

value of EHD, the greater the gas capacity of the tubing

1 1/4 37 EHD 639 456 374

FOR LP GAS

Maximum Capacity of Pipe in Thousands of BTU per Hour of Undiluted Petroleum Gases (at 11 inches Water Column Inlet

Pressure) (Based on a Pressure Drop of 0.5 Inch Water Column).

* EHD = Equivalent Hydraulic Diameter. The greater the

value of EHD, the greater the gas capacity of the tubing.

Nominal

iron

Length of Flexible Corrugated Stainless Steel Tubing (CSST), Feet

Tube

size

Black Iron Pipe

pipe

Length of Pipe, Feet

inches

EHD*

Inches

80 100 125 150 200

1/2

3/4

291 200 160 137 122 110 94

84 74 67 58

1/2

3/4

18 EHD 129 91

608 418 336 287 255 231 197 175 155 140 120

1145 787 632 541 480 434 372 330 292 265 227

23 EHD 254 183 151

30 EHD 521 365 297

131

256

118

227

107

207

Maximum Capacity of Semi-Rigid (flexible, non

corrugated) Tubing in Thousands of BTU per Hour of

Undiluted Liquefied Petroleum Gases (at 11 inches

Water Column Inlet Pressure).

Copper

Outside

diameter

Inch

Length of Tubing, Feet

10 20

39 26

92 62

30 40

21 19

50 41

60 70 80 90 100

3/8

1/2

35 31 29 27 26

72 67 62 59 55

(Based on a Pressure Drop of 0.5 Inch Water Column)

5/8 199 131 107 90

* Source National Fuel Gas Code NFPA 54, ANSI

Z223.1 - No Additional Allowance is necessary for an

ordinary number of fittings

3/4 329 216 181 145 131 121 112 104 95 90

Fig. 29

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Installation instructions

or flush the lines before connecting to the water

heater.

3.9 Water connections

Warning: This heater is not approved

B Full port shutoff valves should be installed on both

the cold water supply and hot water outlet lines to

facilitate servicing the heater (see Fig. 31).

for preheated water applications.

See chapter 3.11 for approved

recirculating application.

B For installation on a private well system with the use

of a pressure tank, the lowest pressure range setting

recommended is 40-60 psi (2.75 and 4.15 bar).

Warning:

In applications where inlet water

temperature can exceed 140°F (60ºC), a

3-way valve or mixing valve must be

installed before the appliance to prevent

water exceeding 140°F (60°C) from

entering the appliance.

3.10 Water quality

Water quality can have an impact on appliance

longevity and may not be covered under the

manufacturer's warranty.

For water analysis data call your local water department,

or if on a well, have well water analyzed periodically. If

water quality exceeds one or more of the values

specified below, Bosch recommends consulting a local

water treatment professional for water softening/

conditioning options.

B When facing the heater, the ¾” cold connection is on

the bottom right and the hot connection is on the bot-

tom left. Centrally locating the water heater is recom-

mended to keep hot water distribution times even

throughout the structure.

Description

Max. Levels

6.5 - 8.5

500

TDS (total Dissolved

Solids)

mg/l or ppm

100

(6 grains)

Total hardness

Aluminum

Chlorides

Copper

COLD

2.0

250

1.0

HOT

Fig. 30

B The use of unions when connecting both water

pipes to the inlet and outlet connections is

required. This will facilitate any necessary

servicing.

Iron

0.3

B Plastic or PEX type plumbing line materials are not

suitable for connecting directly to the water heater.

Manganese

0.05

5.0

B Although water piping throughout the building may

be other than copper, we recommend that copper or

suitably rated stainless steel flex line piping be used

for the water connections for 1.5’ on either side of

the water heater (follow local codes if more

stringent).

Zinc

Table 13

B Never sweat any piping directly to or beneath

the water connections, as damage can occur to

the internal water valve from heating of the

pipe.

B Keep water inlet and outlet pipes to no less

than ¾" (19.05mm) diameter to allow the full

flow capacity.

B If the cold and hot connections to the heater are

reversed, the heater will not function. Be certain there

are no loose particles or dirt in the piping. Blow out

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Installation instructions

Connecting the pressure relief valve (PRV)

3.11 Domestic hot water recirculation

A listed pressure relief valve supplied with the heater

must be installed at the time of installation. No valve is

to be placed between the PRV and the heater. No

reducing coupling or other restriction may be installed

in the discharge line. The discharge line must be a min-

imum of 4” above a drain and installed such that it

allows complete drainage of both the PRV and the line.

The discharge line must be placed where it will not

cause any damage.

The location of the PRV must be readily accessible for

servicing or replacement, and be mounted as close to

the water heater as possible. See Fig. 31. To install the

PRV, a suitable fitting connected to an extension on a

“T” fitting can be sweated to the hot water line.

Support all piping.

Although recirculation directly through the tankless

water heater is allowed, temperature stability is

improved by recirculating through a mini-tank as shown

in Fig. 32. By using the design in Fig. 32, there is no

recirculation of hot water through the tankless water

heater and therefore, does not affect the heat

exchanger warranty. Direct recirculation through the

tankless water heater is permissible, however, the heat

exchanger warranty is reduced; contact Bosch

Thermotechnology for further installation requirements.

The following drawing is provided to outline one

possible recirculation design using the water heater in

conjunction with an Ariston mini tank water heater. This

schematic is for illustration only and must not be used

for actual installation without appropriate engineering

and technical advice from

properly licensed

professional in the locality where the installation is

made.

GWH

2700

Fig. 31 Plumbing Connections (with shutoff valves)

and Pressure Relief Valve

6720608158-77.1AL

Ariston Minitank

Water filter

Fig. 32 Recirculation application

Full port isolation valve

Circulator (pump)

Check valve

PRV

Expansion tank

The use of a small electric mini-tank water heater (4-6

gallon size) should be used for this application and

designed so the pump will circulate the water through

the mini-tank and the building's hot water return loop

only. Timed or thermostatically controlled operation of

the pump is commonly done. Contact Bosch

Thermotechnology if further information is needed.

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Installation instructions

B Record lowest operating gas pressure reading in

table 15.

3.12 Measuring gas pressure

Confirm gas pressure upon installation.

Connecting manometer

Gas pressures lower than 3.5" W.C. for Natural Gas or

8" W.C. for LPG will result in insufficient degree rise to

the hot water being used, reduced hot water volume,

possible error code faults and must be corrected. See

Gas Connections, chapter 3.8, page 22.

B Shut off gas supply at installer supplied shutoff valve

for this water heater.

B Remove front cover and locate inlet gas pressure

measuring point (see Fig. 34).

B Loosen screw inside left test point fitting (do not

remove) and connect manometer tube to test point.

Remove screw completely if correct size tapping is

available.

Static Pressure Test

B Turn gas supply back on.

B Record static gas pressure reading in table 15.

Operating Pressure Test

B Press ON/OFF button to turn off the appliance.

B Press and hold "Program" (P) button and press ON/

OFF button to turn appliance ON.

Fig. 34 Gas pressure test port (left tapping)

Static Gas Pressure Reading (see Chapter 3.12)

enter here: ___________________ Date: ___________

Operating Gas Pressure Reading (see Chapter 3.12)

enter here: ___________________ Date: ___________

Table 15

Fig. 33

B As soon as '188' is displayed, release "Program"

, button and the display should read P2.

B Press

until P1 appears.

Note: While in this mode the appliance will run

constantly at maximum power and allow

maximum water flow.

For inlet gas pressure adjustment consider the

following table:

Gas type

LPG

3.5” WC

8” WC

Table 14

Minimum inlet gas pressure under full operation

B Turn on high volume of hot water flow (at least 6

gpm) and heater will ignite. If heater display reverts to

P2, open more hot water fixtures to allow sufficient

flow. Press

until P1 reappears on display.

B Operate all other gas appliances on the same gas

piping system at maximum output.

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Electrical connections

4.1 Electrical power supply

4.2 Position of the fuses in control unit

To check fuses, proceed as follows:

Warning:

For

safety

reasons,

B Remove the front cover, see Fig. 4, page 6.

disconnect the power supply cord to

the heater before any service or testing

is performed.

B Remove the three screws on front of the control unit.

Warning: This heater must be

electrically grounded in accordance

with the most recent edition of the

National Electrical Code. NFPA 70. In

Canada, all electrical wiring to the

heater should be in accordance with

local codes and the Canadian Electrical

Code, CSA C22.1 Part 1. Do not rely

on the gas or water piping to ground the

metal parts of the heater.

Fig. 36

B Pull control unit free to access and remove the six

screws from the back cover of the control unit, see

Fig. 37, pos. 2.

The water heater requires an electrical power supply

from a 120VAC / 60Hz properly rated receptacle and

must be properly grounded.

B Check the fuses in the printed circuit board, see Fig.

37, pos. 3.

The heater is wired as shown in the wiring diagram

(chapter 9, Fig. 59).

Fig. 35 Connecting power supply cord

Power cord length: 3ft.

Note: Outlet appliance is plugged in to should be

clear from possible water damage.

6720608158-78.1AL

Fig. 37 Location of fuses

B After verifying the fuses mount all parts in reverse

order.

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Operation instructions

Fig. 38

On/Off button

Reset button

Program Key

LCD display

Up button

Down button

LED - Power On indicator or Stand-by

5.1 LCD Display functions

Fig. 42 Lock indicator

Fig. 43 Flame indicator

Fig. 44 Remote control

Warning: Do not use any cleaning or

corrosive agent to clean the window.

Fig. 39 Power bar indicator

Fig. 40 Temperature indicator

Fig. 41 Error indicator

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Operation instructions

5.2 For your safety read before

operating your water heater

5.4 Temperature selection

To select output water temperature:

B Press buttons

temperature.

in order to reach desired

Warning: If you do not follow these

instructions exactly, a fire or explosion

may result causing property damage,

personal injury or loss of life.

A. This appliance is equipped with electronic ignition for

lighting the main burner. When turning the heater on,

follow these instructions exactly.

B. Before operating the unit, press the On/Off button.

WHAT TO DO IF YOU SMELL GAS

B Do not try to light any appliance.

B Do not touch any electric switch; do not use any

phone in your building.

Fig. 46

B Immediately call your gas supplier from a neighbors

phone. Follow the gas supplier’s instructions.

Setting the water temperature

The desired temperature of the hot water can be

adjusted on the front control panel of the heater.

The water heater has an electronically controlled gas

valve that modulates the burner input in response to

both varying hot water flow rates and/or changes in any

incoming and outgoing water temperatures.

B If you cannot reach your gas supplier, call the fire

department.

C. Use only your hand to press the on/off control switch.

Never use tools. Follow these instructions exactly. If

control switch is jammed, close the gas supply and call

a qualified service technician. Attempted forceful repair

may result in a fire or explosion.

D. Do not use this appliance if any part has been under

water. Immediately call a qualified service technician to

inspect the appliance and to replace any part of the

control system and any gas control which has been

under water.

Note: The water heater, running at minimum BTU, may

still achieve temperatures above the desired set

temperature. Low flowing fixtures are the leading cause

of this type of temperature overshoot. To combat this

symptom, clean fixtures or replace with higher flowing

ones.

Saving water resources:

B Make sure you close all the taps after any use. Avoid

leaving the taps dripping. Repair any leaking tap.

5.3 Power

B Define the temperature you want, in the appliance or

with the remote control. This way you have the

precise water flow needed (mixing cold water to

regulate temperature will increase the water flow with

consequent waste of water).

B To start the appliance press the On/Off button.

Fig. 45

Off

B To shut down the appliance press the On/Off button

again.

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Operation instructions

5.5 Use of optional remote control

accessory (part no. TSTAT2)

Fig. 50 Reset button

If the problem persists, contact your installer.

5.8 Program button

Program button can be used on the appliance and in the

remote control.

Fig. 47 Remote control

The wireless remote control accessory (Fig. 71,

component 13) and the temperature selector buttons

on the front of the water heater operate identically.

Contact your distributor to order the remote control

accessory. Modification of the water heaters interior

control unit (Fig. 71, component 16) is required when

programming the remote control with this heater.

Programming “Program” function

Programming actions are similar for both controls

(appliance control pad and wireless remote control).

NOTE: up to 6 remote controls can be

programmed for one single water heater,

each with a range distance of 98 ft (30 m).

Fig. 51 “Program” key

5.6 Operation

B When a hot water tap is opened, main burner ignites

and LCD displays the symbol

Memorizing selected temperature

B Press buttons

memorized.

to select temperature to be

B Hold “Program” button for 3 seconds to save

temperature.

When LCD stops blinking, temperature is saved in

memory.

Fig. 48

Using “Program” function

In order to select memorized temperature

B LCD blinks until selected temperature is reached.

B Press “Program” key.

5.7 Reset button

LCD shows pre-memorized temperature, which is now

the hot water selected temperature.

If the LCD shows the error symbol

power or unplug the heater.

do not shut off

See the error code on LCD and consult

“Troubleshooting” section.

5.9 Locked condition

This condition is only valid for appliances with remote

controls.

Fig. 52 Locked condition

Fig. 49

Whenever LCD shows

the temperature setting

After

“Troubleshooting” section.

following

instructions

indicated

cannot be adjusted because the appliance is in use by

a user which already selected a different temperature.

Appliance will be automatically unlocked five minutes

after closing the hot water tap.

B press reset button to return heater to normal

operation.

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Maintenance and service

Pressure relief valve

Warning: Always turn off the electrical

power supply, turn off the manual gas

shut off valve and turn off the water shut

off valves whenever servicing.

• Manually open the pressure relief valve to ensure

proper operation.

Inlet water filter

• Verify the inlet filter screen is clean and undamaged.

The inlet water filter is located inside the cold water

inlet fitting on the right side of the appliance (See

Fig. 53, page 32). Close installer supplied cold water

shutoff and loosen slotted screw on inlet fitting.

Water will drain from the appliance. Remove

cylindrical filter inside.

Caution:

B Check and clean the complete water

heating system once a year.

B Carry out a maintenance overhaul if

necessary. Immediately repair defects to

avoid damage to the system.

Annual maintenance table

Every year

1. Inspect venting system

2. Inspect combustion chamber

3. Inspect burner

4. Inspect condensate trap

5. Inspect water filter

Table 16 Annual maintenance

Fig. 53 Water filter

The unit should be checked once a year by a gas

technician. If repairs are needed, the repairs should be

done by a gas technician.

Inlet water filter

Water filter

Descaling

• In areas where the water supply has a high mineral

content (see Table 13, page 25), the heat exchanger

should be periodically flushed with a descaling

solution. Scale build up will shorten the life of the

water heater and damage resulting from scale is not

covered under warranty. Refer to section 6.3 for

detailed instructions on descaling the heat

exchanger.

6.1 Annual maintenance

(To remove front cover, see page 6.)

Venting System

• Venting system - inspect inside of flue pipe for any

blockage or restriction. Observe burner flames

during heater operation. (Vent pipe must be

removed). Inspect the combustion air inlet pipe for

blockage or debris. Inspect combustion air and

exhaust terminations for blockage or debris.

Heat exchanger fin coils

• Inspect heat exchanger fincoil for soot build-up or

blockage. To access fincoil, venting must be

removed from flue gas exhaust accessory. With

venting removed and inspect fincoil below with a

flashlight. If there is evidence of soot build-up or

blockage, the heat exchanger should be removed by

a professsional and cleaned thoroughly. To remove

the heat exchanger, consult service bulletin at

www.boschhotwater.com.

Combustion chamber

• Inspect burner observation window (Fig. 64, #10) for

cracks or spillage of flue gases. Observe burner

flames during heater operation. Flames should be

steady and blue with no signs of yellowing. Yellow

burner flames are an indication of improper

combustion. Refer to Section 3.4 & 3.3 of this

manual to ensure that exhaust system and

combustion air supply meets manufacturer's

specifications.

6.2 Winterizing for seasonal use

Installation instructions state that the water heater must

not be installed in a location where it may be exposed to

freezing temperatures. If the heater must be left in a

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Maintenance and service

space which is likely to experience freezing

temperatures, all water must be drained from the heater.

If precautions are not taken, resulting damage will not

be covered under the warranty. NOTE: Use of agents

such as anti-freeze is not permitted as they may cause

damage to the water heater's internal components.

9. Fill tank with descaling solution so both lines inside

are submersed. We recommend straight white

vinegar. If using a commercial descalant, refer to

manufacturer's instructions on dilution with water.

10.Operate the circulating pump.

11.Make sure there are no leaks and the solution is

flowing from the descaling reservoir through the

heater and returning to the reservoir.

1. Press ON/OFF switch on the water heater to turn

OFF the heater and unplug power supply cord. The

display should be blank.

12.Run solution through the heater until the solution

returning to the descaling reservoir comes out clear.

(Changing to a fresh solution may be necessary

during this process).

2. Shut off gas supply to heater.

3. Shut off the water supply to the water heater using

installer supplied shutoff valve.

13.Disconnect all lines and drain all solution from heat

exchanger. Properly discard of solution.

4. Open hot water taps to drain the plumbing system. If

water continues to flow after 5 minutes, a plumbing

crossover is present and must be corrected before

proceeding.

14.Position a container below the hot water outlet and

connect cold water supply. Open cold water supply

isolation valve and flush heat exchanger with clean

water.

5. Open service valves (if available) or disconnect inlet

and outlet water pipes from the water heater. Place a

small bucket underneath the water heater to catch

residual water remaining inside the water heater.

15.Shut cold water shutoff valve and reconnect hot

water supply to the water heater.

6. Using an air compressor, blow short bursts of air

(100psi max) through the outlet water connection

until there is no water present coming through the

inlet water connection of the heater.

16.Reconnect electrical supply to unit, open water

shutoff valves, and return the unit to service.

7. Reconnect water fittings and return heater to service

when danger of freezing has past.

6.3 Mineral scale build-up

Periodic descaling may be necessary in areas with high

mineral content in the water. Scale buildup in the heat

exchanger may result in lower flow rates, error codes of

A7 and E9 and boiling sounds (knocking and banging)

in the heat exchanger.

Descaling using a pump

1. Disconnect electrical supply from the water heater.

2. Shut off the water supply to the water heater using

(installer supplied) shutoff valve.

3. Open hot water taps to drain and relieve pressure

from the plumbing system.

4. Drain water from the unit's heat exchanger by

disconnecting inlet and outlet water connections

from the heater.

Fig. 54

5. Connect a line (A) from the outlet of the circulating

pump (installer supplied) to the inlet water fitting on

the water heater (see Fig. 54).

6.4 Adjusting CO (carbon dioxide)

The CO₂can only be adjusted by a certified gas

technician with a calibrated CO₂analyzer.

6. Using another line (B), connect to the water outlet

fitting on the water heater. Route the other end of this

line into a descaling reservoir.

Caution: One factor that may affect

CO₂levels is improper gas pressure.

Please see Chapter 3.12 for the

procedure to measure gas pressure

and record your findings below:

7. Using a 3rd line (C) from the descaling reservoir,

connect to the inlet side of circulating pump. Install a

filter on the end of this line in the descaling reservoir.

8. Make sure all connections are "water tight.".

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Maintenance and service

Static Gas Pressure:

“ WC

B Record the CO₂reading in P1 below. (Analyzer

reading may take several minutes to stabilize).

P1 Operating Pressure:

B Press the ‘ ’ button until P2 appears. Unit will

ramp down to low fire and the flow should decrease.

The P1 minimum operating gas pressure is 3.5" WC for

Natural Gas and 8" WC for Propane. Do not proceed in

adjusting CO₂until pressure is at or above these levels,

but not to exceed 10.5” WC for Natural Gas and 13”

WC for Propane.

B Record the CO₂reading in P1 and P2 below.

P2 CO₂Reading:

% CO₂

P1 CO₂Reading:

% CO₂

A. Once Gas Pressure is adequate

C. Adjusting CO₂:

B Press ON/OFF button to turn off the heater.

Note: P1 adjustment will change the P2 reading.

Confirm the P1 value BEFORE adjusting the P2 level.

B Remove brass flat head screw on the exhaust collar

as seen in Fig. 55.

1. If P1 CO₂level is off:

B Insert CO₂analyzer probe into the measuring port.

The tip of the probe should be in the center of the flue

pipe (approx 1.5" inserted). Avoid air gaps between

probe and measuring port as they can alter readings.

B Loosen yellow painted philips screw (1) and cover

should rotate down (2) revealing a recessed brass

slotted screw. Fig. 57.

B Turning the slotted screw counter clockwise will

raise P1 CO₂levels and clockwise will lower P1

CO₂levels. Adjustments to the slotted screw will

also change P2 CO₂levels.

B After bringing the P1 CO₂readings in proper range,

press the

button to enter the P2 mode. Verify

CO₂readings in P2 mode.

2. If P2 CO₂level is off:

B Remove yellow painted #40 Torx cover from the front

of the gas valve. (Fig. 58) A plastic #40 Torx screw

will be revealed.

Fig. 55 Measuring port

B Turning the plastic #40 Torx screw counter

clockwise will lower P2 CO₂levels and clockwise

will raise P2 CO₂levels.

B While holding the Program (P) button in, press the

ON/OFF button to turn ON the heater (see Fig. 56).

As soon as ‘188’ flashes on the display, release the

Program button. The display should now read P2.

Note: This screw adjustment is very sensitive and

should be made in small increments. It may take several

minutes for readings to stabilize.

Press

button until “P1” appears on display.

3. Verify both P1 and P2 CO₂readings are within the

ranges specified in table 17. Repeat steps 1 and 2 as

necesssary until CO₂values are within the specified

ranges.

4. Once CO₂values are within the specified ranges,

verify the CO readings on P1 and P2 do not exceed

values shown in table 17. If values exceed this limit,

inspect vent system and fin coils (chapter 6.1, page 32)

for blockage.

D. Returning to Service:

Fig. 56

1. Return slotted screw cover to original position and

tighten philips screw.

2. Reinstall Torx cover.

B. Measuring CO₂(combustion cover must be

installed):

3. Remove CO₂analyzer probe and reinstall flathead

screw with gasket in exhaust collar.

4. Press ON/OFF button to turn OFF the heater and

then turn ON the heater.

B Open all hot water taps to achieve a flow rate of at

least 6 gallons per minute. (1 tub and 2 sinks should

be sufficient). If heater display reverts to P2, open

more hot water fixtures to allow sufficient flow. Press

5. Heater is ready for normal operation.

‘

’ until P1 reappears on the display.

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Maintenance and service

Max. CO

level

(measured)

CO₂range (%)

Nat. Gas

7.5 % - 8.1 %

2.3 % - 2.6 %

LP Gas

max. input

min. input

< 250 ppm

< 60 ppm

max. input

min. input

8.7 % - 9.3 %

2.7 % - 3.0 %

< 250 ppm

< 60 ppm

* Values above are for climate controlled conditions.

Inputs such as gas pressure, heating value of the gas,

humidity and temperature of combustion air all impact CO

and CO₂values. Changes in these inputs can result in

different CO and CO₂values on the same appliance.

Table 17 CO₂& CO target numbers

Final Readings

P2 CO₂Reading:

% CO₂

P1 CO₂Reading:

Fig. 57 Adjusting P1 CO₂level

6720608158-38.1AL

Fig. 58 Adjusting P2 CO₂level

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Maintenance and service

Refer to chapter 6.6 Control board diagnostics (page

37) regarding how to access these P-modes.

6.5 Program values

This section describes details on programming the

appliance. For most applications the factory default

values will robust and stable operation. Only adjust the

factory settings if the installation requires changes as

indicated in the appropriate section of this manual.

Caution: Misadjusted program

values can lead to appliance

malfunction, errors, and service

calls.

Program Description

Factory Default MIN MAX

Comment

Maximum Power

NG: 48, LP: 46

NG: 50, LP: 49 see chapter 3.12, page 27.

note: reducing P1 values below

maximum will reduce maximum

power of the appliance.

Minimum Power

see chapter 3.3.6, page 17

see chapter 5.5, page 31

Remote Con-

trols installed

Access to Diag-

nostic Mode

10f

see chapter 6.6, page 37

contact Bosch for details

Cascade Mode

°F

°C

Temperature

Unit

Appliance Type

Back light

Condensing / Non-condensing*

dE turns back light off after 60

seconds from last button

pushed, ON turns backlight on

permanently

Fan Purge

runs secondary and primary fan

when P9 is selected by

depressing the “P” - button

Table 18 Program values, factory default settings and ranges.

* Incorrect setting causes errors.

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Maintenance and service

6.6 Control board diagnostics

Diagnostic menu

1. Turn on/off switch on water heater to off (O) position.

Entry/Exit into sub-modes

Set-point temperature (°F)

2. Press and hold the program (

) button while

turning the on/off switch to the on (I) position. The

display will cycle through a startup procedure

including the software version.

Inlet water temperature (°F)

Outlet water temperature (°F)

Water flow (gallons/min)

Gas type (LP or NG)

3. Release the '

' button when '188' appears on the

display. The display should read 'P2' when the

program button is released. If not, repeat process.

4. Press and release the '

' button on the control

Fan speed (Hz)

panel until the display reads 'P4'. You are now in the

diagnostic mode of the control board.

Burner power (%)

Maximum power (kW)

Back flow temperature (°F)

5. When the display reads 'P4', press and release the

'E'.

' button once again and the display should read

Flue gas temperature (°F)¹⁾

not used, settting 00

6. Use the '

' and '

' button on the control board

to cycle through different diagnostic modes

available.

Most recent error/failure

2nd most recent error

3rd most recent error

4th most recent error

5th most recent error

6th most recent error

7th most recent error

8th most recent error

9th most recent error

10th most recent error

7. Once in the selected diagnostic mode of your

choice, press and release the '

the diagnostic information.

' button to display

EXAMPLE: to read the flow rate in gallons per minute

while the unit is flowing water, cycle to the '3d' mode

and press the '

' button. A reading of 25 on the

display would indicate the heater is reading a flow rate

of 2.5 gallons/minute.

8. Once the information is obtained, press the '

button again to return to the diagnostic mode menu

and scroll to addition diagnostic information.

10F

9. To exit the diagnostic mode of the heater, use the

Table 19

' or '

' button until the display reads 'E'.

Available only on model GWH C800 ES

10.Press the '

should read P4.

' button once again and the display

11.Turn the on/off switch off (O) and back on (I) again

to return heater to normal function.

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Troubleshooting

and mixing valves are common causes of plumbing

crossovers.

Warning: If you are unable to perform

the tasks listed below, or need

additional assistance please contact

your original installer or licensed gas

technician.

8. With the ON/OFF switch turned to OFF (O) position

and the power supply cord unplugged, remove the

unit's front cover (See Page 6. Fig 3). Check wire

connections between the water valve, control unit

and electrode set. See chapter 12.1, page 49 for

location of these parts.

7.1 Introduction

Many of the questions customers ask regarding

operation of this unit can be answered by following the

troubleshooting steps as outlined below. Visit our web

site at www.boschhotwater.com for more detailed

troubleshooting and service bulletins. For best results,

perform each step before proceeding to the next. The

suggested solutions may require that the cover be taken

off. (See Page 6. Fig. 3).

7.3 Water is too hot

1. Selected temperature on the unit is set too high. To

lower output temperature, see chapter 5.4, page 30.

2. Clean inlet filter screen per chapter 6.1, page 32.

3. Inspect the water path for obstructions. Make sure all

showerheads, faucet aerators and whole house

filters are clear of debris.

4. Confirm the heater's gas type coincides with the type

of gas being supplied. See Fig. 2, page 6 for location

of rating plate.

7.2 Burner do not ignite when hot

water is turned ON

1. If the display is blank, verify power to outlet.

(120VAC/60Hz properly grounded circuit required).

Verify that the heater ON/OFF button is turned ON.

5. Avoid restrictive outlets. Clean all showerheads and

faucet aerators. It may be necessary to upgrade to

higher flow rate shower heads if allowable by local

code.

2. Verify the fuses in the control board are good. See

Section 4.2, page 28 of the installation manual for

fuse locations.

6. In areas where the water has a high mineral content,

periodic descaling may necessary. See chapter 6.3,

page 33 for directions.

3. Make sure cold water inlet connection is plumbed to

the right side of heater when facing unit. See Fig. 30,

page 25.

7. Ensure the outlet temperature sensor is making

contact and firmly mounted on the hot water pipe.

4. A minimum of 0.65 gallons per minute (GPM) (2.5 l/

m) is required to activate the heater. A quart

container should fill in 25 seconds or less to activate

heater. In areas of warm inlet water temperatures, the

heater may increase activation rate to as high as 1.6

gallons per minute (GPM) to prevent overshooting of

set temperature.

7.4 Water is not hot enough

1. Selected temperature on the unit is too low. To raise

output temperature, see chapter 5.4, page 30.

2. Clean inlet filter screen. See chapter 6.1, page 32.

3. Inspect the water path for obstructions. Make sure all

showerheads, faucet aerators and whole house

filters are clear of debris.

5. Clean inlet filter screen per chapter 6.2, page 32.

6. Inspect the water path for obstructions. Make sure all

showerheads, faucet aerators and whole house

filters are clear of debris.

4. Confirm the heater's gas type coincides with the type

of gas being supplied. See Fig. 2, page 6 for location

of rating plate.

7. The heater activates when the water flow through the

unit is at or above the required minimum of 0.65

GPM (2.5 l/m). A crossover in the plumbing creates

back pressure on the water flowing through the

heater. Therefore, a higher flow rate than normal is

needed to force the heater to activate. To check for

a plumbing crossover, shut off the cold water supply

to the water heater. Then open all of the hot water

taps served by the heater. Wait 10 minutes and

check for water flow at taps. There should be no

water flowing. Any continuous flow of water, small or

large, indicates a crossover is present and must be

corrected. Consult a professional plumber for help in

correcting a crossover. Failing single lever faucets

5. Check inlet gas particle screen for blockage at gas

inlet connection on bottom of unit.

6. Verify gas pressure is in accordance with

specifications in chapter 3.12, page 27. A gas

pressure reading is needed to proceed further.

Contact your original installer or a local certified gas

technician to obtain this reading.

7. Cold water is mixing into the hot water lines

(plumbing crossover). A plumbing crossover can

unintentionally mix cold water with the hot water

leaving the heater. The end result is a cooler water

temperature than desired. To check for a plumbing

crossover, shut off the cold water supply to the water

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Troubleshooting

heater. Then open all of the hot water taps served by

the heater. Wait 10 minutes and check all taps for

water flow. There should be no water flowing. Any

continuous flow of water, small or large, indicates a

crossover and must be corrected. Consult a

professional plumber for help in correcting a

crossover. Failing single lever faucets and mixing

valves are common causes of plumbing crossovers.

higher pressure cold water at the tap, the lower

pressure hot water can be overpowered. This will

shut down the burners because the hot water flow

rate fell below the minimum flow rate required for

activation. Verify inlet filter screen is clean and clear

of debris. See chapter 6.1, page 32 for inlet filter

cleaning instructions.

3. Heater deactivated by temperature balancing valves.

If the outlet water temperature is set too high, the

heater can produce temperatures that are too hot. A

temperature balance shower valve will automatically

mix in cold water to reduce the hot water

temperature. In the event of any temperature

instability at a fixture using a temperature balancing

valve, refer to the valve manufacturer for instructions

on internal adjustment setting. An adjustment should

be made to minimize the amount of cold water the

valve is adding. Additionally, the temperature setting

on the heater can be lowered to prevent the

temperature balance valve from mixing in too much

cold water.

8. Ensure the outlet temperature sensor is making

contact and firmly mounted on the hot water pipe.

7.5 Low water flow/pressure

1. Too many hot water applications are being used

simultaneously or too much flow is demanded. The

water heater will effectively support two 2.0-2.5

GPM shower heads simultaneously or multiple sink

applications. Greater draws will result in a water

pressure drop and reduced flow at taps.

2. Ensure that gas pressure is in accordance with

specifications in chapter 3.12, page 27. A gas

pressure reading is needed to proceed further.

Contact your original installer or a local certified gas

technician to obtain this reading. If gas pressure is

inadequate, the water heater will close its motorized

water valve, reducing the hot water flow rate in an

attempt to reach the selected output temperature.

4. Inlet water pressure is erratic due to fluctuating

supply water pressure. For installation on a private

well system with the use of a pressure tank, the

lowest pressure range setting recommended is 40-

60 psi (2.75 - 4.15 bar). Consult your installer or

local plumber for effective ways to maintain constant

water pressure to the water heater when on a well

system.

3. If selected temperature on the unit is set too high for

the demanded flow rate, the water heater will close

its motorized water valve, reducing the hot water flow

rate in an attempt to reach the selected output

temperature. Lowering the selected temperature will

allow the motorized water valve to open up for

increased water flow rate.

7.7 Noisy burner/heater during

operation

1. Sealed combustion leak. Make sure combustion

cover is securely fastened. Ensure the exhaust vent

adaptor is properly sealed with supplied gasket.

Leaky seals create improper combustion resulting in

noise.

4. Clean inlet filter screen per chapter 6.1, page 32.

5. Inspect the water path for obstructions. Make sure all

showerheads, faucet aerators and whole house

filters are clear of debris.

2. Improper venting. Venting that is unsealed, the wrong

material, too big in diameter or too long in run will

result in unstable burner flames and noise. Ensure

venting is proper and in accordance with

specifications in chapter 3.3, page 9.

7.6 Hot water temperature fluctuates

at tap

1. Hot water is very hot out of the tap, requiring mixing

of cold water in order to attain a useable hot water

temperature. The addition of too much cold water will

overpower the hot water flow from the tankless water

heater.

3. Lack of adequate combustion air. Drawing

combustion air from a room area of inadequate size

will result in unstable burner flames and noise.

Improper use of piping for combustion air will result

in unstable burner flames and noise. Ensure

adequate combustion air is provided to the unit in

accordance with specifications in Section 3.4, page

20, Combustion Air Requirements.

This slows the flow within the tankless water heater,

decreasing it below activation point, which shuts off

the burners. The end result is nothing but cold water

coming out of the outlet.

Consult www.boschhotwater.com for a detailed

service bulletin on overcoming temperature

fluctuations.

4. Cross contamination. Ensure that intake and exhaust

terminations maintain minimum required clearances

stated in the manual. Cross contamination between

intake and exhaust may cause unstable burner flames

and noise.

2. Unbalanced pressure in water lines. Any restriction in

the water heater, such as a clogged inlet filter screen,

can result in unequal pressures between the cold

and hot water lines. In such cases, when mixing in the

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Troubleshooting

5. Lack of adequate gas pressure. Inadequate gas

pressure will cause the fuel-to-air mixture (CO₂) to be

out of adjustment. This will result in unstable burner

flames and noise. Ensure gas pressure is in

accordance with specifications in section 3.12, page

27 Measuring Gas Pressure. A gas pressure reading

is needed to proceed further. Contact your original

installer or a local certified gas technician to obtain

this reading.

6. Verify proper CO₂readings per chapter 6.4, page

33. CO₂adjustments must be done by a certified

gas technician with a calibrated combustion gas

analyzer.

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Problem solving

8.1 Error code diagnostics

To remove error code from the

display, press the reset button.

Display

Cause

Solution

Fault in the flue gas limiter.

1. Check continuity of the flue gas limiter (see Fig. 64, page 49).

Go to steps two and three to determine air box temperature

sensor fault and replace it.

2. Check for flue gas leakage around the top and bottom seals of

heat exchanger as well as the viewing window.

3. Check that venting is within specifications (see Section 3.3).

Long vent lengths, venting with more than three elbows, blocked

vent or combination venting may cause this failure.

4. Check that flue gas limiter connector and spade connections

are secure.

5. Unplug heater and check the two main plug connections inside

the control board.

Appliance selection on “P7” mode 1. Check “P7” mode: water heater requires setting “NC”.

is not correct.

2. Check jumper and connection on sensor at upper right hand

corner of heat exchanger.

3. Measure jumper resistance, must be 115-125 ohms.

Backflow temperature sensor 1. Check backflow temperature sensor connection and resistance.

defect - happens if sensor is See Fig. 62 page 47 and Fig. 64, page 49

disconnected or short circuit. 2. Replace backflow temperature sensor.

Outlet temperature sensor fault 1. Check red wire connections at hot water temperature sensor.

(Temperature below freezing or Clean terminals with an eraser. If badly corroded, replace sensor

above 210°F).

and wire harness. See Fig. 64, page 49.

2. Sensor may trip if water temperature drops below freezing to

protect heater from freezing conditions. Any damage due to

freezing conditions is not covered under warranty.

3. Clean inlet filter screen and clear any debris out of shower

heads, faucet aerators and whole house filters.

4. In areas where water has a high mineral content, periodic

descaling may be necessary.

Table 20

* By installer or service technician only.

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Problem solving

Display

Cause

Solution

(Flashing)

Outlet temperature sensor not 1. Check that the sensor is firmly attached to the hot water pipe

expected

sensing

temperature.

output (see Fig. 70, page 55).

2. Clean inlet filter screen and clear any debris out of shower

heads, faucet aerators and whole house filters.

3. Check venting specifications are met. Long vent lengths,

venting with more than three elbows, blocked vent or combination

venting may cause this failure.

4. Check gas pressure. Low gas pressure may prevent the heater

from reaching desired output temperature.

5. Check supply voltage. It must be 120VAC and properly

grounded.

6. Possible defective control unit call Bosch Water Heating for

further instructions.

7. Ensure that outlet temperature sensor is not placed on any

bends in the hot water pipe or misreading may occur.

Primary fan rotation too low on 1. Disconnect power supply cord and check wire connections on

operation.

back side of primary fan and the two connectors on the control

board (see Fig. 71, page 56).

2. Check supply voltage. It must be 120VAC and properly

grounded.

3. Check venting specifications are met. Long vent lengths,

venting with more than three elbows, blocked vent or combination

venting may cause this failure.

4. Ensure intake and exhaust terminations maintain the required

minimum clearances stated in the manual. Cross contamination

between intake and exhaust may cause the fan to alter its

rotational speed.

5. Check gas pressure. Low gas pressure may cause the fan to

change its speed to meet desired temperature.

6. Possible defective control unit call Bosch Water Heating for

further instructions.

No rotational speed sensor signal 1. Disconnect power supply cord and check wire connections on

from primary fan.

back side of primary fan and the two connectors on the control

board (see Fig. 71, page 56).

2. Check supply voltage. It must be 120VAC and properly

grounded.

3. Possible defective component in fan or defective control unit

call Bosch Water Heating for further instructions.

(Flashing)

Water flow signal over specified 1. Disconnect power supply cord and check wire connections on

water valve and the two connectors on the control board (see

Fig. 71, page 56).

maximum value.

Water flow > 10 gallon/min.

2. Excessive water pressure and flow. Ensure water pressure is

less than 150psi and flow rate is below 10 gallons per minute.

Internal hardware/software failure.

1. Disconnect power supply cord and check the two wire and

ground connections on control board as well as ground connection

on heater chassis.

2. Pushing the wrong combination of buttons on the control unit

can create confusion among the microprocessors inside. In this

case, the error code should not happen more than once or twice.

Turn off the water heater. Turn water heater back on and try

resetting error code. Use the reset button (

codes.

) to reset any error

3. Possible defective control unit. Call Bosch Water Heating for

further instructions.

Table 20

* By installer or service technician only.

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Problem solving

Display

Cause

Solution

Over-temperature detected by 1. Check that the sensor is firmly attached to the vertical section of

outlet temperature sensor on hot the hot water pipe (see Fig. 70, page 55).

water pipe.

Temperature > 185°F

2. Check red wire connections at outlet temperature sensor.

Clean terminals with an eraser. If badly corroded, replace sensor

and wire harness. Check sensor resistance (see Fig. 60

3. Clean inlet filter screen per chapter 6.2

page

page 32 and clear any

debris out of shower heads, faucet aerators and whole house

filters.

4. In areas where water has a high mineral content, periodic

descaling may be necessary. See chapter 6.3

page 32 for

directions.

Cold water temperature sensor 1. Check connector on wires coming from top of watervalve for a

fault.

secure connection. See Fig. 64, page 49.

2. Sensor may trip if water temperature drops below freezing to

protect heater from freezing conditions Any damage due to

freezing conditions is not covered under warranty.

Backflow temperature sensor over 1. Check combustion air and backflow vent piping for blockage.

309°F. 2. Check if secondary fan connections are disconnected.

The appliance will close the burner 3. Check venting specifications are met. Long vent lengths,

and lock.

venting with more than three elbows, blocked vent or combination

venting may cause this failure.

4. Check sensor resistance (see Fig. 62 page 47).

Overheat sensor (ECO) open 1. Disconnect power supply cord and check wire connections on

circuit (should reset when cooler overheat sensor (top right of heat exchanger) and the two

temperatures are detected).

connectors on the control board. See Fig. 64, page 49.

2. Check white wire connections at overheat sensor. Clean

terminals with an eraser. If badly corroded, replace sensor and

wire harness.

3. Check venting specifications are met. Long vent lengths,

venting with more than three elbows, blocked vent or combination

venting may cause this failure.

4. Clean inlet filter screen and clear any debris out of shower

heads, faucet aerators and whole house filters.

5. In areas where water has a high mineral content, periodic

descaling may necessary, see chapter 6.3

6. Unplug power supply cord to the water heater. Open a hot

water tap for several minutes to allow cold water to pass through

heat exchanger. Close hot water tap and disconnect lead wires to

overheat sensor. Using a multimeter, check continuity through

overheat sensor contacts. Replace sensor if open.

Table 20

* By installer or service technician only.

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Problem solving

Display

Cause

Solution

No flame ionization detected with 1. Verify that all manual gas shut off valves are open.

water flow.

2. Check gas type, see Fig. 2, page 6.

3. Reset error code and open a water tap to cycle the heater in an

effort to purge air on new installations. Cycling hot water tap on

and off multiple times may be necessary. If heater still faults with

EA error code, have a licensed gas technician properly purge air

out of the gas line leading to the water heater.

4. Check three wire connections to ignition group on the lower

front of the heat exchanger are secure.

5. Check gas pressure, see chapter 3.12 page 27.

6. Check venting specifications are met. Improper venting may

cause premature failure of the flame sensor rod.

7. Check that the minimum power fan speed has been adjusted to

the proper value. See page 18.

8. Observe inside the viewing window of the heat exchanger when

a hot water tap is opened. Sparking should be followed by a

steady blue flame. If flame is unstable or yellow with proper gas

pressure, confirm CO₂readings per section 6.4

Ionization failure during operation.

1. Check gas type, see Fig. 2 page 6

2. Check three wire connections to ignition group on the lower

front of the heat exchanger are secure.

3. Check venting specifications are met. Improper venting may

cause unstable burner flames and loss of flame ionization.

4. Check that the minimum power fan speed has been adjusted to

the proper value. See page 18.

5. Check gas pressure, see section 3.12 page 27.

6. Check and adjust CO₂readings, see section 6.4, page 33.

Ionization error at standby.

1. Loose connection to the flame ionization rod. Verify that the

thinner wire leading from the control unit is securely connected to

the flame sensor located on the lower front of the heat exchanger.

See Fig. 64, page 49.

2. Flame ionization rod or control unit may be damaged. Contact

Bosch Water Heating for further instruction.

Gas leakage error, gas valve circuit 1. Disconnect power supply cord and check wire connections on

not closing properly.

gas valve and the two connectors on the control board.

2. Flow water out of a hot water tap above the minimum activation

point of 0.65 GPM. Measure voltage at the gas valve wire plug

connection. The voltage should measure 24VDC between the left

pair of wires and 24VDC between the right pair of wires when the

unit is operating. If voltage is not proper, contact Bosch Water

Heating for further instruction.

3. Gas valve may be defective, contact Bosch Water Heating for

further instruction.

Table 20

* By installer or service technician only.

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Electrical diagram

T=104°C

T=220°F

T=110°C

T=230°F

Casc.

input

Casc.

output

Back flow

...

JP2

JP8

JP6

JP7

JP5

6720608542-04.1AL

Fig. 59 Electrical scheme

Intlet water temperature sensor

Outlet water temperature sensor

Backflow temperature sensor

Cascading output connection

Cascading input connection

Ionization sensor

Water flow sensor

Flue gas limiter

Heat exchanger overheat sensor (ECO)

Gas valve

Jumper resistance

Water valve

Primary fan

ON/OFF switch

Secondary fan

AC plug

Main connection

Ignition electrodes

Ground post

Antifreeze kit connection

Fuse

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Sensor resistance charts

10 Sensor resistance charts

Outlet temperature sensor characteristics

110

10 5

10 0

9 5

9 0

8 5

8 0

6 5

6 0

4 5

4 0

3 5

3 0

2 5

2 0

2 2 2

2 17

2 12

2 0 7

2 0 2

19 7

19 2

18 7

18 2

177

172

16 7

16 2

157

152

14 7

14 2

13 7

13 2

12 7

12 2

117

112

10 7

10 2

9 7

9 2

8 7

8 2

6 7

6 2

4 7

4 2

3 7

3 2

10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37

Resistance (Kohm)

Fig. 60

Inlet temperature sensor characteristics

12 0

2 4 7

2 4 2

115

110

10 5

10 0

9 5

9 0

8 5

8 0

6 5

6 0

4 5

4 0

3 5

3 0

2 5

2 0

2 3 7

2 3 2

2 2 7

2 2 2

2 17

2 12

2 0 7

2 0 2

19 7

19 2

18 7

18 2

177

172

16 7

16 2

157

152

14 7

14 2

13 7

13 2

12 7

12 2

117

112

10 7

10 2

9 7

9 2

8 7

8 2

6 7

6 2

4 7

4 2

3 7

3 2

Resistance (Kohm)

Fig. 61

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Sensor resistance charts

Back Flow characteristics

155

150

14 5

14 0

13 5

13 0

12 5

12 0

302

297

292

287

282

277

272

267

262

257

252

247

242

237

232

227

222

217

212

207

202

197

192

187

182

177

172

167

162

157

152

147

142

137

132

127

122

117

112

107

102

115

110

10 5

10 0

9 5

9 0

8 5

8 0

6 5

6 0

4 5

4 0

3 5

3 0

2 5

2 0

15 16

19 20

21 22 23 24 25 26 27 28 29 30

31 32 33 34 35 36 37

Resistance (Kohm)

Fig. 62

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GWH 2700 ES Functional scheme

11 GWH 2700 ES Functional scheme

Fig. 63 Functional scheme

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Interior components diagram and parts list

12 Interior components diagram and parts list

12.1 Interior components

Fig. 64 Components

Flue gas collector

Heat exchanger

Flame sensor

Ignition electrodes

Observation window

Backflow temperature sensor

Secondary air fan

Primary fan (Mixer)

Outlet temperature sensor

LCD display

Gas valve

Water valve with engine and temperature sensor

On/Off button

Reset button

Control unit

Up button

Down button

LED

Program key

Flue gas limiter

Heat exchanger overheat sensor (ECO)

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Interior components diagram and parts list

Fig. 65 Appliance overview

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Interior components diagram and parts list

12.2 Components diagram

12.2.1 Group 1

6720902973.AA JF

Fig. 66 Components Diagram

Item

Description

Reference

Item

Description

Front cover

Reference

8 705 431 286

8 705 506 862

8 701 103 140

8 703 401 170

8 700 506 300

8 704 701 084

8 705 600 003

8 708 104 103

8 703 403 012

Combustion cover clip

Grommet set

8 701 201 032

8 710 203 039

8 705 504 162

8 700 103 710

8 708 006 022

8 700 103 166

8 705 504 116

8 701 309 164

Cover shield

Exhaust accessory

Gasket exhaust

Inlet air cover

Trade mark badge

Cover screw

Combustion cover

Combustion cover gasket

Observation window

Holding bracket

Screw

Inlet air gasket

Inlet air accessory

Mounting bracket

Table 21

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Interior components diagram and parts list

12.2.2 Group 2

6720902974.AA JF

Fig. 67 Components Diagram

Item

Description

Site window

Reference

Item

Description

Reference

8 705 406 422

8 704 701 052

8 705 700 153

8 707 206 204

8 704 701 054

8 701 000 401

8 701 302 249

8 700 205 147

8 710 303 027

Heat exchanger

Ignition group

Heat exchanger top gasket

Flue gas collector

Heat exchanger O-ring

Rubber grommet

Overheat sensor (ECO)

Heat exchanger bottom gasket

Table 22

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Interior components diagram and parts list

12.2.3 Group 3

6720902975.AA JF

Fig. 68 Components Diagram

Item Description

Reference

Item Description

Reference

8 708 120 699

8 704 701 087

8 707 204 071

8 707 206 459

8 704 701 097

2 915 011 006

8 707 204 094

8 707 204 072

8 703 403 012

8 705 700 170

Air duct O-ring

Venturi

8 700 205 149

8 700 306 226

8 700 205 224

8 704 701 059

2 910 642 150

8 701 004 049

8 705 700 155

2 910 952 122

Main burner

Burner gasket

Primary fan

O-ring

Mixer / Fan gasket

Screw

Backflow temperature sensor

Washer

Plate gasket

Air supply duct

Screw

Fan mount nut

Secondary fan - NG

Secondary fan - LPG

Screw

Table 23

Gas / Air Mixer

Table 23

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Interior components diagram and parts list

12.2.4 Group 4

6720608158-73.1AL

Fig. 69 Components Diagram

Item

Description

Reference

Item

Description

Gas valve

Reference

8 707 021 019

8 703 404 219

8 700 203 041

8 700 703 136

8 703 300 041

8 700 715 389

8 700 103 014

Gas filter

8 700 507 002

8 704 701 085

8 705 202 140

8 704 701 062

8 703 404 220

8 700 205 009

2 910 149 181

Gasket

Pressure tapping

Washer

Gas / Fan connector

Washer

Pressure balance tube

Pressure balance nut

Gas supply pipe

Gas valve washer

Regulation screw

O-ring

Screw

Table 24

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Interior components diagram and parts list

12.2.5 Group 5

Fig. 70 Components Diagram

Item Description

Reference

Item Description

Reference

8 708 505 024

8 700 205 147

8 700 715 394

8 701 201 028

8 700 715 469

8 700 400 015

8 703 305 349

8 710 103 045

8 701 300 025

Inlet fitting with filter

8 703 305 356

Water valve with engine

O-ring

8 700 205 157

8 716 102 607

8 700 507 059

8 700 103 764

8 700 205 231

Cold water pipe

Pipe connection clip

Hot water pipe

Watervalve clip

Water filter

Washer

Temperature sensor

Outlet fitting

O-ring

Table 25

Inlet / Outlet washer

Wireform spring

Table 25

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Interior components diagram and parts list

12.2.6 Group 6

6720902978.AA JF

Fig. 71 Components Diagram

Item Description

Reference

Item Description

Reference

8 707 207 257

1 904 521 342

8 700 609 008

8 704 401 371

8 704 401 378

8 704 401 347

8 704 401 348

8 704 401 376

Electrode cables

Flue gas limiter

8 704 401 346

8 700 400 032

7 709 003 617

7 709 003 665

8 707 207 153

8 700 201 012

8 703 401 109

8 708 300 123

Control unit

Fuse T2.5A

Cascading kit (optional)

Anti freeze kit

Fuse T1.6A

Power supply cables

Power supply cord

Fan cables

Remote control (optional)

Shaped seal (optional)

Screw (optional)

Wire harness

Jumper

Printed circuit transceiver (optional)

Table 26

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Protecting the environment

13 Protecting the environment

Packing

The packing box may be fully recycled as confirmed by

the recycling symbol

Components

Many parts in the heater can be fully recycled in the end

of the product life. Contact your city authorities for

information about the disposal of recyclable products.

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Limited Warranty

14 Limited Warranty

General

Service Labor Costs

Aquastar water heaters are warranted by the

Manufacturer

Thermotechnology Corp..

This warranty does not cover any labor costs

associated with service, removal or re-installation of

part(s). All such costs must be borne by the Purchaser.

Additionally, this warranty does not cover any labor

costs associated with service, removal, installation or

re-installation of the original water heater or a replaced

water heater.

(BOSCH)

through

Bosch

Bosch thermotechnology corporation will furnish a

replacement heat exchanger and will furnish a

replacement of any other part which fails in normal use

and service within the applicable periods specified

below, in accordance with the terms of this warranty.

The Bosch Thermotechnology Corp. replacement will

be warranted for the unexpired portion of the original

warranty. This warranty will be valid only for water

heaters in possession of the original purchaser as

recorded on the warranty card.

NOTE: the water heater must be free of

damaging scale deposits and not subject

to gas pressures greater than those

shown on the rating plate, which must not

be altered, defaced or removed.

The Heat Exchanger

How to Make a Claim

If the heat exchanger fails within twelve (12) years after

the original installation and operation, Bosch

Thermotechnology Corp. will furnish a replacement

heat exchanger. However, if the water heater is used

within an approved hot water recirculation and supplied

with circulated water, this heat exchanger warranty is

limited to three (3) years from date of original installation

and operation. If the water heater is installed in other

than a single family dwelling, this heat exchanger

warranty is limited to two (2) years from date of original

installation and operation.

Any claim for warranty parts should be made to your

local dealer or distributor:

BOSCH THERMOTECHNOLOGY CORP.

340 Mad River Park

Waitsfield, VT 05673

TEL. 800-642-3111

www.boschhotwater.com

In most cases, the dealer or distributor will be able to

promptly honor your claim and subsequently notify

Bosch Thermotechnology Corp.. However, all

replacements are made subject to validation by Bosch

Thermotechnology Corp. of in-warranty coverage. The

damaged or defective item must be made available in

exchange for the replacement.

Exceptions

This warranty will not apply:

• 1. to defects or malfunctions resulting from failure to

properly install, operate or maintain the unit in

accordance with the printed instructions provided;

Miscellaneous

• 2. to damage or abuse, accident, neglect or freezing

and other acts of nature;

No one is authorized to make any other warranties on

behalf of Bosch Thermotechnology Corp.. It is

expressly understood that the replacement warranty of

Bosch Thermotechnology Corp. shall be in lieu of any

and all other warranties, express or implied, including

warranties of merchantability or fitness for a particular

use or purpose, and further that Bosch

Thermotechnology Corp. shall not be liable for any loss

or damage directly or indirectly arising from the use of

the hot water heater, or for any consequential damages

arising from such use (including damages from water

leakage). Bosch Thermotechnology Corp. sole liability

with respect to any defect shall be for the replacement

of the defective part(s). Some states do not allow such

limitations and exclusions, so the above may not apply

to you.

• 3. to damage resulting from operation with either the

flame sensor rod or overheat sensor removed;

• 4. to failure of the heat exchanger resulting from the

operation of the water heater in a corrosive

atmosphere or at water temperatures exceeding the

maximum rating, or if the water heater is not supplied

with potable water;

• 5. to defects or damage cause by any attachment

or modification, including any energy-saving device.

• 6. to damage resulting from scale deposits and/or

highly mineralized / unsoftened water supply.

All Other Parts

If any other part fails within five (5) years after original

installation and operation, Bosch Thermotechnology

Corp. will furnish a replacement part free of charge.

This warranty gives specific legal rights. You may also

have other rights which vary from state to state.

6 720 608 542

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Limited Warranty

6 720 608 542

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6720608542

Installer Checklist to be completed by installer upon installation

Serial Number

___ ___ ___ ___ ___ ___ ___ ___

(8 digit serial number is located on rating plate on right side panel)

Gas Pressure Reading*

Building Water Pressure

Installing Company

Installer name

Static__________

__________

Operating__________

Range if on Well system __________

_____________________________________________

Address

Phone

* See Chapter 3.12, page 27 and gas pressure table (to be filled out by installer)

Installation manual should be left with the owner after the installation is tested and completed

Replacement Parts available from:

BOSCH THERMOTECHNOLOGY CORP.

50 Wentworth Avenue

Bosch Termotecnologia SA

Londonderry, NH 03053

Estrada de Cacia

Tel. 866-330-2730

3801 - 856 Aveiro - PORTUGAL

www.boschhotwater.com

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