Bosch Appliances Water Heater GWH 260 PN HN2 User Manual

Applications manual  
For tankless and point of use water heaters  
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Applications manual  
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1 Introduction  
The Bosch Applications Manual is intended to present some of the  
most common applications of the Bosch line of tankless and point of  
use water heaters. Application drawings are shown with both piping  
and corresponding electrical schematics where applicable. Auxiliary  
equipment depicted does not necessarily represent any one manu-  
facturer or specic model number. There are a wide variety of  
techniques, practices and piping strategies possible when installing  
water heating appliances. It is the responsibility of the installing  
contractor to determine the most suitable arrangement for the  
application.  
Although this manual covers many common applications for our  
products, system possibilities are virtually endless. Should you  
encounter an application that is not covered in this manual or have  
any questions regarding any of its content, we encourage you to  
contact your local sales representative or us directly at Bosch Water  
Heating.  
This is not a substitute for any of the product’s installation manuals.  
All specications subject to change.  
Installation must conform with local codes or, in the absence of  
local codes, the National Fuel Gas Code ANSI Z 223.1/NFPA 54.  
In Canada: Installation must conform with CGA B149.(1,2) INSTAL-  
LATION CODES and/or local installation codes.  
2 Bosch Water Heating Models  
This section describes the water heaters available from Bosch Water  
Heating. The information given in each section provides a general  
overview to the specications of that particular model. More detai-  
led information is contained in the installation manuals. Download  
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Applications manual  
2.1 Sizing tankless water heaters  
Denitions  
Major applications (2 GPM or more): Washing machine, bath tub,  
shower nozzle  
Minor applications(1.5 GPM or less): Low ow shower head,  
bathroom sink, kitchen sink  
Rule of thumb sizing  
The tables below provide a general rule of thumb when sizing for  
most residential applications. For commercial applications or for a  
more detailed sizing method, use the instructions below in conjunc-  
tion with the charts on the next page.  
Sizing by Chart  
Measure the ow rates at each xture that will be used simultane-  
ously and add them together. If only one application will be used  
at a time measure each xture and use the maximum ow rate  
observed.  
Rule of Thumb Sizing  
Model Number  
Number of Major  
Applications  
Number of Minor  
Applications  
GWH 715 ES  
GWH C 800 ES  
GWH 425 HN/PN/EF  
GWH 425 HN/PN/EF  
GWH 260 PN  
2
2
1
0
1
1
1
0
1
1
2
0
0
1
RP17PT  
RP27PT  
Using a known volume container, record several ll times. Per-  
form the calculation below to determine the ow rate (a one  
gallon ll time of 30 seconds is 2.0 gallons per minute (GPM):  
Volume (gallons)  
Fill time (sec)  
sec  
min  
Flow rate (GPM) =  
x
60  
Using a thermometer, measure the incoming water temperature.  
Subtract this temperature from the desired hot water temperature  
to get the degree rise. So, if the desired hot water temperature is  
120F and incoming temperature is 55F, the desired degree rise is  
65F.  
This example requires a ow rate of 2.0 GPM at a 65˚F rise. The  
data point is shown on each graph. Since the demand is above  
the GWH 260 PN capacity, this application would require a GWH  
425 HN/PN/EF gas tankless water heater. The electrical model  
used for this application would be the RP27PT electric tankless  
water heater.  
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GPM  
8
7
6
5
4
3
2
1
0
GWH
C
8
00 ES  
GWH 715 ES  
GWH
4
25
PN/HN  
GWH 260 PN/HN  
10  
20  
30  
40  
50  
60  
70  
80  
90  
Degree rise (°F)  
Gas Appliance Sizing Chart  
GPM  
4.0  
3.5  
3.0  
2.5  
2.0  
RP27PT  
R
P
17PT  
1.5  
1.0  
R
P
12PT  
RP1P  
RP7P  
RP3P  
0.5  
0.0  
RP9P  
80  
10  
20  
30  
40  
50  
60  
70  
90  
Degree rise  
Electric Appliance Sizing Chart  
Note: Maximum flow rates dependant on site conditions  
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Applications manual  
2.2 Bosch GWH 715 ES  
Features:  
GWH 715 ES Installation Clearances  
Electronic ignition and built in power vent  
82% thermal efciency  
Vents vertically or horizontally with 3" or 4" stainless steel (AL29-  
4C)  
Top (A)  
12"  
Front (B)  
Back  
1"  
0"  
Direct vent room-sealed combustion  
Computerized temperature control — ensures temperature stability  
Model GWH 715 ES N for natural gas (NG) supply  
Model GWH 715 ES L for liquid propane (LP) supply  
15-year warranty  
Sides  
1"  
Floor (C)  
12"  
Qualies for $300 tax credit  
GWH 715 ES Technical Specications  
Gas input  
Natural Gas: 19,900 - 199,000 BTU  
LP Gas: 19,900 - 199,000 BTU  
0.65 gallons per minute (gpm)  
3ft minimum  
distance  
Minimum ow to activate  
Flow rates  
45˚F rise @ 7.2 gpm  
55˚F rise @ 5.9 gpm  
65˚F rise @ 5.0 gpm  
77˚F rise @ 4.2 gpm  
90˚F rise @ 3.6 gpm  
Thermal Efciency  
Dimensions  
NG: 82% LP: 82%  
30½" h x 17" w x 11¼" d  
Weight  
67 lbs.  
yes  
Modulating gas valve  
Ignition  
3ft minimum  
distance  
Electronic  
Accessories  
Outdoor kit (PTOK)  
Wireless Remote (TSTAT2)  
Tankless Link Cascading Kit (TLINK)  
Freeze Prevention Kit (8700400022)  
Water Filter Kit (8703305356)  
Fig. 1 Venting congurations  
Installation guidelines:  
Venting:  
Must be 3" or 4" AL29-4C sealed stainless steel vent pipe.  
Slope horizontal runs up to termination ¼" per foot. The last  
horizontal section of exhaust vent pipe between last elbow and  
termination must slope down to the termination ¼" per foot.  
Do not combination vent with any other appliance.  
Install condensate drain where applicable.  
GWH 715 ES Installation Specications  
Gas connection  
¾" Male NPT  
¾" Male NPT  
Water connections  
NG gas pressure  
Minimum: 4" W.C.  
Maximum: 14" W.C.  
LP gas pressure  
Minimum: 9" W.C.  
Maximum: 14" W.C.  
See manual for vent terminator clearances.  
Water pressure  
(Static)  
Minimum: 30 PSI  
Minimum well pressure: 40 PSI  
Maximum: 150 PSI  
Gas piping:  
Heater will not function properly without adequate supply gas  
pressure.  
Any appliance connector should be ¾" minimum diameter  
Electrical supply  
Venting  
120VAC - plugs in  
3" or 4" stainless steel (AL29-4C)  
direct vent  
Plumbing:  
room-sealed combustion  
Install the included pressure relief valve and pipe to suitable  
drain.  
Minimum piping diameter is ¾".  
Do not solder directly to the bottom of the unit.  
Use unions to facilitate easy future maintenance.  
Use full port ball valves for isolation valves.  
Partially ll condensate drain tube loop (where applicable) with  
water prior to start up.  
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2.3 Bosch GWH C 800 ES  
Features:  
Electronic ignition and built in power vent  
Condensing technology with 92% thermal efciency  
Vents vertically or horizontally with 3" or 4" PVC, CPVC or ABS  
(Schedule 40) vent pipe.  
Direct vent room-sealed combustion with concentric venting  
option  
Computerized temperature control — ensures temperature stability  
Model GWH C 800 ES N for natural gas (NG) supply  
Model GWH C 800 ES L for liquid propane (LP) supply  
15-year warranty  
GWH C 800 ES Installation Clearances  
Top (A)  
12"  
Front (B)  
Back  
1"  
0"  
Sides  
1"  
Floor (C)  
12"  
Qualies for $300 tax credit  
GWH C 800 ES Technical Specications  
Gas input  
Natural Gas: 19,900 - 199,000 BTU  
LP Gas: 19,900 - 199,000 BTU  
0.65 gallons per minute (gpm)  
MAINTAIN 12 IN.  
(18 IN. FOR CANADA)  
MINIMUM CLEARANCE  
Minimum ow to activate  
VENT  
ABOVE  
HIGHEST ANTICIPATED  
Flow rates  
45˚F rise @ 8.0 gpm  
55˚F rise @ 6.4 gpm  
65˚F rise @ 5.5 gpm  
77˚F rise @ 4.6 gpm  
90˚F rise @ 3.9 gpm  
SNOW LEVEL.  
COMBUSTION  
AIR  
MAXIMUM OF 24 IN.  
ABOVE ROOF.  
ROOF BOOT/  
FLASHING (FIELD  
SUPPLIED  
MINIMUM  
1”  
Thermal Efciency  
Dimensions  
NG: 92% LP: 92%  
INTAKE  
EXHAUST  
VENT  
INTAKE  
30½" h x 17" w x 11¼" d  
EXHAUST  
COMBUSTION  
Weight  
74 lbs.  
yes  
AIR  
DRAIN TEE  
Modulating gas valve  
Ignition  
DRAIN TEE  
Electronic  
Accessories  
Outdoor kit (PTOK)  
Wireless Remote (TSTAT2)  
Tankless Link Cascading Kit (TLINK)  
Freeze Prevention Kit (8700400022)  
Water Filter Kit (8703305356)  
Concentic Termination Kit  
(BWH60L46)  
Fig. 1 Venting congurations  
Installation guidelines:  
Venting:  
Must be 3" or 4" PVC, CPVC or ABS (Schedule 40) vent pipe.  
Attach drain for internal condensate siphon and dispose of  
according to local codes.  
GWH C 800 ES Installation Specications  
Gas connection  
¾" Male NPT  
¾" Male NPT  
Water connections  
NG gas pressure  
Minimum: 4" W.C.  
Maximum: 14" W.C.  
Do not combination vent with any other appliance.  
Install an external condensate drain where applicable.  
See manual for vent terminator clearances.  
LP gas pressure  
Minimum: 9" W.C.  
Maximum: 14" W.C.  
Water pressure  
(Static)  
Minimum: 30 PSI  
Minimum well pressure: 40 PSI  
Maximum: 150 PSI  
Gas piping:  
Heater will not function properly without adequate supply gas  
pressure.  
Any appliance connector should be ¾" minimum diameter  
Electrical supply  
Venting  
120VAC - plugs in  
3" or 4" PVC, CPVC, or ABS  
(Schedule 40) direct vent sealed  
combustion  
Plumbing:  
Install the included pressure relief valve and pipe to suitable  
drain.  
Minimum piping diameter is ¾".  
Do not solder directly to the bottom of the unit.  
Use unions to facilitate easy future maintenance.  
Use full port ball valves for isolation valves.  
Partially ll condensate drain tube loop (where applicable)  
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Applications manual  
2.4 Outdoor Installation for GWH 715 ES,  
and GWH C 800 ES  
Installation on wood siding  
Outdoor Kit (PTOK) installation:  
The installation of this outdoor kit (PTOK) is required when  
installing either of the above appliances outdoors  
Outdoor cap easily retrots to these indoor models  
Outdoor kit comes with Freeze Prevention which must be installed  
Exterior water piping should be protected if freezing conditions  
could exist  
Minimum clearances:  
Installation on vinyl siding:  
Min.  
distances  
Ref.  
Description  
A
B
Directly below or adjacent to  
an opening; operable  
windows, doors and any fresh  
air openings  
4 ft  
C
D
From any adjacent wall  
4 ft  
3 ft  
Below a gutter, sanitary  
pipework, eaves or overhang  
E
F
Above ground  
1 ft  
5 ft  
From a gas meter or gas  
regulator  
G
Outdoor Installation Clearances  
Source: NFPA 54 National Fuel Gas Code  
ANSI Z223.1  
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2.6 Bosch GWH 345 ESR  
Features:  
Specically designed for recirculating applications  
Electronic ignition and built in power vent  
GWH 345 ESR thermal efciency of 82%  
Vents vertically or horizontally with 3" stainless steel (AL29-4C)  
Direct vent room-sealed combustion  
Computerized temperature control — ensures temperature  
stability  
Model GWH 345 ESR N for natural gas (NG) supply  
Model GWH 345 ESR L for liquid propane (LP) supply  
10-year warranty  
GWH 345 ESR Technical Specications  
Gas input  
GWH 345 ESR: 32,000 - 95,000 Btu/h  
GWH 345 ESR: 3.5gpm @ 45°F rise  
Fig. 1 Venting congurations  
Maximum ow rates  
Installation guidelines:  
Thermal Efciency  
Dimensions  
82%  
27.5" h x 15.75" w x 11.75" d  
Venting:  
Must be 3" or 4" AL29-4C sealed stainless steel vent pipe.  
Weight  
47 lbs.  
yes  
Slope horizontal runs up to termination ¼" per foot. The horizon-  
tal section between last elbow and termination must slope down  
to the termination ¼" per foot.  
Modulating gas valve  
Ignition  
Electronic  
Do not combination vent with any other appliance.  
Always install an external condensate drain except when termi-  
nating horizontally with less than 3 feet of pipe.  
See manual for vent terminator clearances.  
GWH 345 ESR Installation Specications  
Gas connection  
¾" Male NPT  
¾" Male NPT  
Water connections  
NG gas pressure  
Gas piping:  
Minimum: 5.5" W.C.  
Maximum: 14" W.C.  
Heater will not function properly without adequate supply gas  
pressure.  
Any appliance connector should be ¾" minimum diameter  
LP gas pressure  
Minimum: 11" W.C.  
Maximum: 14" W.C.  
Electrical supply  
Venting  
120VAC - plugs in  
Plumbing:  
3" stainless steel (AL29-4C)  
direct vent  
room-sealed combustion  
Install the included pressure relief valve and pipe to suitable  
drain.  
Minimum piping diameter is ¾".  
Do not solder directly to the bottom of the unit.  
Use unions to facilitate easy future maintenance.  
Use full port ball valves for isolation valves.  
Partially ll condensate drain tube loop with water prior to start  
up.  
GWH 450 ESR Installation Clearances  
Top (A)  
12"  
Front (B)  
Back  
1"  
0"  
Sides  
1"  
Floor (C)  
12"  
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2.6 Bosch GWH 450 ESR  
Features:  
Specically designed for recirculating applications  
Electronic ignition and built in power vent  
GWH 450 ESR thermal efciency of 81%  
Vents vertically or horizontally with 3" stainless steel (AL29-4C)  
Direct vent room-sealed combustion  
Computerized temperature control — ensures temperature  
stability  
Model GWH 450 ESR N for natural gas (NG) supply  
Model GWH 450 ESR L for liquid propane (LP) supply  
10-year warranty  
GWH 450 ESR Technical Specications  
Gas input  
GWH 450 ESR: 45,000 - 120,000 Btu/h  
GWH 450 ESR: 4.5gpm @ 45°F rise  
Fig. 1 Venting congurations  
Installation guidelines:  
Venting:  
Maximum ow rates  
Thermal Efciency  
Dimensions  
81%  
27.5" h x 15.75" w x 11.75" d  
Must be 3" or 4" AL29-4C sealed stainless steel vent pipe.  
Slope horizontal runs up to termination ¼" per foot. The horizon-  
tal section between last elbow and termination must slope down  
to the termination ¼" per foot.  
Weight  
47 lbs.  
yes  
Modulating gas valve  
Ignition  
Electronic  
Do not combination vent with any other appliance.  
Always install an external condensate drain except when termi-  
nating horizontally with less than 3 feet of pipe.  
GWH 450 ESR Installation Specications  
Gas connection  
¾" Male NPT  
¾" Male NPT  
See manual for vent terminator clearances.  
Water connections  
NG gas pressure  
Gas piping:  
Minimum: 5.5" W.C.  
Maximum: 14" W.C.  
Heater will not function properly without adequate supply gas  
pressure.  
Any appliance connector should be ¾" minimum diameter  
LP gas pressure  
Minimum: 11" W.C.  
Maximum: 14" W.C.  
Electrical supply  
Venting  
120VAC - plugs in  
Plumbing:  
3" stainless steel (AL29-4C)  
direct vent  
room-sealed combustion  
Install the included pressure relief valve and pipe to suitable  
drain.  
Minimum piping diameter is ¾".  
Do not solder directly to the bottom of the unit.  
Use unions to facilitate easy future maintenance.  
Use full port ball valves for isolation valves.  
Partially ll condensate drain tube loop with water prior to start  
up.  
GWH 450 ESR Installation Clearances  
Top (A)  
12"  
Front (B)  
Back  
1"  
0"  
Sides  
1"  
Floor (C)  
12"  
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2.7 Bosch GWH 425 EF  
Features:  
Electronic ignition and built in power vent  
Thermal efciency of 82%  
Vents with 4" stainless steel or galvanized vent pipe  
Specifically designed for horizontal vent terminations  
Modulating gas valve — ensures temperature  
stability  
Model GWH 425 EF N for natural gas (NG) supply  
Model GWH 425 EF L for liquid propane (LP) supply  
15-year warranty  
Qualies for $300 tax credit (LP only)  
GWH 425 EF Technical Specications  
Gas input  
Natural Gas: 28,000 - 130,000 Btu/h  
LP Gas: 28,000- 125,000 Btu/h  
Minimum ow to  
0.5 gallons per minute (GPM)  
activate  
Maximum ow rates  
4.6 gpm @ 45°F rise  
Fig. 1 Venting congurations  
Installation guidelines:  
Venting:  
Thermal Efciency  
Dimensions  
NG: 80%  
LP: 82%  
29.75" h x 18.25" w x 8.75" d  
Weight  
44 lbs.  
yes  
Modulating gas valve  
Ignition  
4" AL29-4C sealed stainless steel or 26 gauge galvanized vent  
pipe.  
Electronic  
Slope horizontal runs up to termination ¼" per foot.  
Do not combination vent with any other appliance.  
See manual for vent terminator clearances.  
GWH 425 EF Installation Specications  
Gas connection  
½" Male NPT  
½" Male NPT  
Gas piping:  
Water connections  
NG gas pressure  
Heater will not function properly without adequate supply gas  
pressure.  
Any appliance connector should be ¾" minimum diameter  
Minimum: 7" W.C.  
Maximum: 14" W.C.  
LP gas pressure  
Minimum: 11" W.C.  
Maximum: 14" W.C.  
Plumbing:  
Install the included pressure relief valve and pipe to suitable  
drain.  
Minimum piping diameter is ½".  
Do not solder directly to connections on the bottom of the unit.  
Use full port ball valves for isolation valves.  
Electrical supply  
Venting  
120VAC - plugs in  
4" stainless steel (AL29-4C)  
or 26 gauge galvanized  
GWH 425 EF Installation Clearances  
Top (A)  
12"  
Front (B)  
Back  
4"  
0"  
Sides  
4"  
Floor (C)  
12"  
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Applications manual  
2.8 Bosch GWH 425 HN  
GWH 425 HN Installation Clearances  
Features:  
Hydro-generated ignition  
Top (A)  
12"  
Front (B)  
Back  
4"  
0"  
80% thermal efciency  
Endless hot water for one major application at a time  
Venting: 5" double wall B-vent — natural draft  
Modulating gas valve — constant temperature at varying flow rates  
Model GWH 425 HN N for natural gas (NG) supply  
Model GWH 425 HN L for liquid propane (LP) supply  
15-year warranty  
Sides  
4"  
Floor (C)  
12"  
Qualies for $300 tax credit  
GWH 425 HN Technical Specications  
Gas input  
Natural Gas: 30,735 - 117,000 BTU  
LP Gas: 30,735 - 117,000 BTU  
0.6 gallons per minute (gpm)  
LIS TED VE NT C AP  
Minimum ow to activate  
Flow rates  
45˚F rise @ 4.2 gpm  
55˚F rise @ 3.4 gpm  
65˚F rise @ 2.9 gpm  
77˚F rise @ 2.4 gpm  
90˚F rise @ 2.1 gpm  
MINIMUM 6  
FE ET (1.8M)  
Thermal Efciency  
Dimensions  
NG: 80% LP: 80%  
25.75" h x 16.75" w x 8.5" d  
33 lbs.  
Weight  
LIS TED G AS VE NT  
Modulating gas valve  
Ignition  
yes  
Hydro-generated  
Accessories  
Horizontal vent kit (AQ4) - power  
vent kit for horizontal venting  
E S TAB LIS H A ONE  
F OOT R IS E B E F OR E  
ANY E LB OW S  
GWH 425 HN Installation Specications  
Gas connection  
¾" Male NPT  
¾" Male NPT  
Fig. 2 Venting conguration  
Installation guidelines:  
Venting:  
Water connections  
NG gas pressure  
Minimum: 7" W.C.  
Maximum: 14" W.C.  
LP gas pressure  
Minimum: 11" W.C.  
Maximum: 14" W.C.  
5" minimum diameter — do not reduce vent size  
Refer to installation manual for vent material options  
Do not combination vent with any power vented appliances  
Establish a one-foot rise before any elbows  
Minimum vent height - 6 feet  
Water pressure  
(Static)  
Minimum: 30 PSI  
Minimum well pressure: 40 PSI  
Maximum: 150 PSI  
Electrical supply  
Vertical venting  
120VAC - plugs in  
Horizontal sections must slope upwards at least ¼" for every foot  
of the horizontal length and be properly supported  
5" minimum diameter - natural  
draft  
Gas piping:  
Horizontal venting  
AQ4 horizontal vent kit required  
for horizontal terminations  
Heater will not function properly without adequate supply gas  
pressure  
Any appliance connector should be ¾" minimum diameter  
Plumbing:  
Install the included pressure relief valve and pipe to suitable drain  
Minimum piping diameter is ¾"  
Do not solder directly to connections on the bottom of the unit  
Use full port ball valves for isolation valves  
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2.9 Bosch GWH 425 PN  
GWH 425 PN Installation Clearances  
Features:  
Standing pilot ignition  
Top (A)  
12"  
Front (B)  
Back  
4"  
0"  
78% thermal efciency  
Endless hot water for one major application at a time  
Modulating gas valve — constant temperature at varying flow rates  
Model GWH 425 PN N for natural gas (NG) supply  
Model GWH 425 PN L for liquid propane (LP) supply  
15-year warranty  
Sides  
4"  
Floor (C)  
12"  
GWH 425 PN Technical Specications  
Power input  
Natural Gas: 31,000 - 117,000 BTU  
LP Gas: 31,000 - 117,000 BTU  
0.6 gallons per minute (gpm)  
LIS TED VE NT C AP  
Minimum ow to activate  
Flow rates  
45˚F rise @ 4.2 gpm  
55˚F rise @ 3.4 gpm  
65˚F rise @ 2.9 gpm  
77˚F rise @ 2.4 gpm  
90˚F rise @ 2.1 gpm  
MINIMUM 6  
FE ET (1.8M)  
Thermal Efciency  
Dimensions  
NG: 78% LP: 78%  
25.75" h x 16.75" w x 8.5" d  
33 lbs.  
Weight  
LIS TED G AS VE NT  
Modulating gas valve  
Ignition  
yes  
Standing pilot  
Accessories  
Horizontal vent kit (AQ4) - power  
vent kit for horizontal venting  
E S TAB LIS H A ONE  
F OOT R IS E B E F OR E  
ANY E LB OW S  
GWH 425 PN Installation Specications  
Gas connection  
¾" Male NPT  
¾" Male NPT  
Water connections  
NG gas pressure  
Fig. 4 Venting conguration  
Installation guidelines:  
Venting:  
5" minimum diameter — do not reduce vent size.  
Refer to installation manual for vent material options  
Do not combination vent with any power vented appliances.  
Establish a one-foot rise before any elbows  
Minimum vent height - 6 feet.  
Minimum: 7" W.C.  
Maximum: 14" W.C.  
LP gas pressure  
Water pressure  
Minimum: 11" W.C.  
Maximum: 14" W.C.  
Minimum: 30 PSI  
Maximum: 150 PSI  
Electrical supply  
Vertical venting  
120VAC - plugs in  
5" minimum diameter - natural  
draft  
Horizontal sections must slope upwards at least ¼" for every foot  
of the horizontal length and be properly supported.  
Horizontal venting  
AQ4 horizontal vent kit required  
for horizontal terminations  
Gas piping:  
Heater will not function properly without adequate supply gas  
pressure.  
Any appliance connector should be ¾" minimum diameter  
Plumbing:  
Install the included pressure relief valve and pipe to suitable  
drain.  
Minimum piping diameter is ¾".  
Do not solder directly to the bottom of the unit.  
Use full port ball valves for isolation valves.  
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14  
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2.10 Bosch GWH 260 PN  
GWH 260 PN Installation Clearances  
Features:  
Standing pilot ignition  
Top (A)  
12"  
Front (B)  
Back  
4"  
0"  
78% thermal efciency  
Mounts on wall for easy installation  
Venting: 4" double wall B-vent — natural draft  
Modulating gas valve — constant temperature at varying flow rates  
Model GWH 260 PN N for natural gas (NG) supply  
Model GWH 260 PN L for liquid propane (LP) supply  
15-year warranty  
Sides  
4"  
Floor (C)  
12"  
GWH 260 PN Technical Specications  
LIS TED VE NT C AP  
Gas input  
Natural Gas: 30,735 - 74,900 BTU  
LP Gas: 30,735 - 74,900 BTU  
0.6 gallons per minute (gpm)  
Minimum ow to activate  
Flow rates  
45˚F rise @ 2.6 gpm  
55˚F rise @ 2.1 gpm  
65˚F rise @ 1.7 gpm  
77˚F rise @ 1.5 gpm  
90˚F rise @ 1.3 gpm  
MINIMUM 6  
FE ET (1.8M)  
Thermal Efciency  
Dimensions  
NG: 78% LP: 78%  
28.8" h x 12.2" w x 8.5" d  
25 lbs.  
LIS TED G AS VE NT  
Weight  
Modulating gas valve  
Ignition  
yes  
E S TAB LIS H A ONE  
F OOT R IS E B E F OR E  
ANY E LB OW S  
Standing pilot  
GWH 260 PN Installation Specications  
Gas connection  
¾" Male NPT  
¾" Male NPT  
Water connections  
NG gas pressure  
Fig. 4 Venting conguration  
Installation guidelines:  
Venting:  
Minimum: 7" W.C.  
Maximum: 14" W.C.  
LP gas pressure  
Minimum: 11" W.C.  
Maximum: 14" W.C.  
4" minimum diameter — do not reduce vent size.  
Refer to installation manual for vent material options  
Do not combination vent with any power vented appliances.  
Establish a one-foot rise before any elbows  
Minimum vent height - 6 feet.  
Water pressure  
(Static)  
Minimum: 30 PSI  
Minimum well pressure: 40PSI  
Maximum: 150 PSI  
Electrical supply  
Venting  
120VAC - plugs in  
4" double wall B-vent - natural  
draft  
Horizontal sections must slope upwards at least ¼" for every foot  
of the horizontal length and be properly supported.  
Gas piping:  
Heater will not function properly without adequate supply gas  
pressure.  
Any appliance connector should be ¾" minimum diameter  
Plumbing:  
Install the included pressure relief valve and pipe to suitable  
drain.  
Minimum piping diameter is ¾".  
Do not solder directly to the bottom of the unit.  
Use full port ball valves for isolation valves.  
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2.11 Powerstream Pro RP17PT, RP27PT  
Features:  
Installation guidelines:  
Over 90% efciency rating  
10-year warranty on heat exchanger  
Durable polymer construction  
External temperature control knob  
Thermal cut-out for safety  
Electrical:  
Minimum electrical service for RP17PT is 150 amps.  
Minimum electrical service for RP27PT is 200 amps.  
Minimum wire size for both models is 8 AWG.  
Flow sensor to provide a constant output temperature  
Provides an ENDLESS supply of hot water  
Weighs less than 25 pounds and ts virtually anywhere  
No temperature/pressure relief valve necessary (unless required  
by local codes)  
Plumbing:  
Do not solder directly to connections on the bottom of the unit.  
Use unions to facilitate easy future maintenance.  
Use full port ball valves for isolation valves.  
RP17PT terminal block  
Technical Specications  
Model  
Efciency  
RP17PT  
RP27PT  
90%  
94%  
15 ½" x 15 ¼" x 4 ½"  
15 ½" x 15 ¼" x 4 ½"  
Dimensions  
Weight  
20 lbs.  
¾" Male NPT  
0.6 gpm  
22 lbs.  
¾" Male NPT  
0.8 gpm  
Water ttings  
Activation rate  
Electrical requirements  
Volts  
240  
240  
Kilowatts  
17.25kW  
26.85kW  
U.S.A  
Amps  
80 (2x40 amps)  
80 (1x80 amps)  
120 (3x40 amps)  
120 (1x120amps)  
Canada  
2 independent  
40 amp double-pole  
circuit breakers  
U.S.A  
Wire  
size  
8 AWG  
(4 conductors & ground)  
8 AWG  
(4 conductors & ground)  
Fig. 5 RP17PT Electrical Connections  
Canada  
Check Canadian  
Electrical Code  
(C22.1-02)  
Check Canadian  
Electrical Code  
(C22.1-02)  
RP27PT terminal block  
Phase  
Single  
Single  
Maximum ow rate at given temperature rise  
45°F Rise  
50°F Rise  
60°F Rise  
70°F Rise  
80°F Rise  
2.6 gpm  
2.3 gpm  
2.0 gpm  
1.7 gpm  
1.5 gpm  
4.0 gpm  
3.7 gpm  
3.0 gpm  
2.6 gpm  
2.2 gpm  
3 independent  
40 amp double-pole  
circuit breakers  
Fig. 6 RP27PT Electrical Connections  
Bosch Water Heating  
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Applications manual  
2.12 Powerstream ProRP1P, RP2P, RP3P, RP7P,  
RP9P,RP12PT  
Installation guidelines:  
Features:  
5-year warranty on heat exchanger  
Saves space  
Electrical:  
Refer to the chart below as specication varies by model  
Installs vertically or horizontally (Model RP12PT only installs  
horizontally)  
Plumbing:  
All models must be hardwired  
Solid copper heat exchanger, copper sheathed elements and  
tough plastic housing  
Do not solder directly to connections on the bottom of the unit.  
Use unions to facilitate easy future maintenance.  
Use full port ball valves for isolation valves.  
High/low kW settings possible within most models  
Model RP12PT has thermostatic adjustable control  
Technical Specications  
Model Part #  
RP1P  
Wire Size  
8AWG  
Voltage  
240  
Amps  
High kW  
Low kW  
Degree rise at ow rates (GPM)*  
Activation  
rate (GPM)  
0.5  
0.75  
84°  
42°  
55°  
28°  
28°  
63°  
32°  
84°  
42°  
90°  
1.0  
64°  
32°  
42°  
21°  
20°  
48°  
24°  
64°  
32°  
72°  
1.5  
42°  
21°  
27°  
14°  
2.0  
32°  
16°  
40  
20  
22  
11  
29  
30  
15  
35  
18  
50  
9.50  
4.75  
0.75  
RP2P  
10AWG  
277  
6.00  
81°  
41°  
41°  
0.50  
3.00  
RP3P  
RP7P  
10AWG  
10AWG  
120  
240  
3.40  
7.20  
0.50  
0.75  
32°  
16°  
42°  
21°  
52°  
24°  
12°  
32°  
16°  
42°  
3.60  
RP9P  
8AWG  
6AWG  
277  
240  
9.50  
0.75  
0.75  
4.75  
RP12PT  
12.00  
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| 17  
2.13 Ariston Pro GL2.5Ti, GL4Ti, GL8Ti  
Installation guidelines:  
Features:  
Electrical:  
Point of use mini tank  
3 models  
Follow local codes for electrical outlets for water heaters  
All models plugin to standard wall outlet.  
Adjustable thermostat with thermal cut-out  
Dielectric isolation on inlet/outlet connections  
Units can be wall hung (bracket included) or oor mounted  
Durable poly-composite housing will not dent and resists corrosion  
Temperature/pressure relief valve included (plumb correctly for  
discharge)  
Plumbing:  
Use full port valves for isolation valves.  
Do not solder directly to the plumbing connections.  
Simple 120V AC plug-in connection  
8-year warranty  
Technical Specications  
GL2.5Ti  
GL4Ti  
GL8Ti  
Tank Volume  
Nominal Dimensions  
Voltage  
2.75 gallons  
14" x 14" x 11"  
120V  
3.85 gallons  
14" x 14" x 14"  
120V  
7.0 gallons  
17 ½" x 17 ½" x 14 ½"  
120V  
Amperage  
12.5 amps  
Plug-in  
12.5 amps  
Plug-in  
12.5 amps  
Plug-in  
Wire Type  
Heating Capacity  
Recovery at 90° rise  
Temperature range  
Water connections  
1500 watts  
7 gph  
1500 watts  
7 gph  
1500 watts  
7gph  
65-145°F  
½" NPT  
65-145°F  
½" NPT  
65-145°F  
¾" NPT  
Maximum water  
pressure  
150 PSI  
150 PSI  
150 PSI  
Relief valve  
Installed  
Installed  
Included  
Bosch Water Heating  
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18  
Applications manual  
3 Domestic Water Heating Applications  
Potable water  
Potable water is water that is suitable for drinking. Bosch Water  
Heating appliances are approved to heat potable water only. Heating  
any other liquid other than potable water will void the manufactures  
warranty covering the appliance.  
Introduction  
This chapter covers the various application techniques Bosch Water  
Heating recommends. The schematics are to be used by professional  
contractors in designing a domestic water heating system. The  
applications covered range from single sink point-of-use applications  
to multi-appliance central domestic recirculation applications.  
3.1 Point-of-use applications  
Point-of-use applications cover the small applications that a large  
water heater would be inefcient for. Installing a smaller heater at a  
point-of-use puts the heater near the hot water demand and reduces  
the wait for hot water. Common applications for these appliances  
include homes, ofces, warehouses, service stations, stores, conces-  
sion stands, and summer camps.  
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| 19  
3.1.1 Ariston mini tank  
Simply tap into the cold water line and install the water heater  
directly at the sink. All models plug into a standard 120 volt outlet.  
Heater can be wall mounted, or sit on the oor.  
hot  
cold  
hot  
cold  
Ariston Pro GL2.5 Ti  
Ariston Pro GL4 Ti  
cold  
hot  
Symbols  
Temperature and pressure  
relief valve  
Sink  
Flow direction  
Service valve  
Ariston Pro GL8 Ti  
Drain pan  
Note: This drawing is conceptual in nature and does not address all design, installation or safety considerations.  
Additional safety and/or auxiliary equipment may be needed. This diagram is for reference use by officials, designers and licensed installers.  
It is expected that installers have adequate knowledge of accepted industry practices for the equipment, procedures, and applications involved.  
Drawing is not to scale.  
Drawing # POU1  
CN  
rev 06/06  
Bosch Water Heating  
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20  
Applications manual  
3.1.2 Powerstream Pro electric point-of-use tankless water heater  
PowerstreamPro point-of-use water heaters come in four models to  
serve a wide range of applications. Finding the right model depends  
upon your desired temperature and ow rate. Use the table below to  
nd the model best suited to your customer‘s needs. Flow controls  
and faucet aerators can greatly enhance performance.  
Note: Water heater must be lled with water and purged of air prior  
to supplying power.  
cold supply  
hot  
Powerstream Pro  
RP1P, RP2P, RP3P,  
RP7P, RP9P, RP12PT  
hot  
cold  
cold supply  
hot  
Symbols  
Service valve  
cold  
hot  
Powerstream Pro  
RP1P, RP2P, RP3P,  
RP7P, RP9P, RP12PT  
Sink  
Flow direction  
Note: This drawing is conceptual in nature and does not address all design, installation or safety considerations.  
Additional safety and/or auxiliary equipment may be needed. This diagram is for reference use by officials, designers and licensed installers.  
It is expected that installers have adequate knowledge of accepted industry practices for the equipment, procedures, and applications involved.  
Drawing is not to scale.  
Drawing # POU2  
CN  
rev 06/07  
Application manual | 11.2007  
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| 21  
3.1.3 Bosch GWH-260PN gas tankless water heater  
The Bosch GWH-260PN gas tankless water heater offers  
a compact and lightweight design for easy installation.  
This unit is equipped with standing pilot ignition and is  
intended for low volume applications.  
Symbols  
Temperature and pressure  
relief valve  
BOSCH  
Bosch GWH 260 PN  
Service valves  
Sink  
hot  
cold  
Flow direction  
Low flow  
shower  
Note: This drawing is conceptual in nature and does not address all design, installation or safety considerations.  
Additional safety and/or auxiliary equipment may be needed. This diagram is for reference use by officials, designers and licensed installers.  
It is expected that installers have adequate knowledge of accepted industry practices for the equipment, procedures, and applications involved.  
Drawing is not to scale.  
Drawing # POU3  
CN  
rev 06/07  
Bosch Water Heating  
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22  
Applications manual  
3.2 Whole house applications  
Whole house applications cover the typical home applications up to  
a 2 or 3 bedroom house. See the sizing guide (Section 2.1) to  
determine the best Bosch water heater model for your application.  
An enhanced design including an Ariston mini tank in line to the hot  
water source will reduce the wait time for hot water and improve  
temperature stability.  
3.2.1 Powerstream Pro whole house applications  
The RP17PT and RP27PT must be hard wired directly to the breaker  
box.  
Powerstream Pro  
RP17PT or RP27PT  
Hot  
Cold  
Ariston Pro GL4Ti  
for pipe runs over  
100 ft, use GL8Ti  
Note: place Ariston close to the point of  
use to reduce wait time for hot water.  
Powerstream Pro  
RP17PT or RP27PT  
Symbols  
Hot  
Cold  
Standard tub fixture  
Flow direction  
Service  
valves  
Sink  
Note: Cold water piping to fixtures not shown for clarity purposes.  
Note: This drawing is conceptual in nature and does not address all design, installation or safety considerations.  
Additional safety and/or auxiliary equipment may be needed. This diagram is for reference use by officials, designers and licensed installers.  
It is expected that installers have adequate knowledge of accepted industry practices for the equipment, procedures, and applications involved.  
Drawing is not to scale.  
Drawing # WH1  
CN  
rev 06/07  
Application manual | 11.2007  
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| 23  
3.2.2 Powerstream Pro whole house application with domestic  
recirculation loop  
The circulator should be controlled by an external aquastat, or with  
a timer to run only during times of expected hot water usage.  
Powerstream Pro  
RP17PT or RP27PT  
Cold  
Hot  
Ariston Pro GL4Ti  
(for pipe runs over  
100ft use GL8Ti)  
Symbols  
Bronze circulator pump sized  
Timer or  
Aquastat  
Flow check valve  
Flow direction  
according to UPC standards  
(Taco Bronze 007 or Grundfos 15-42B  
will cover most homes up to 3 bathrooms)  
Potable water  
expansion tank  
Service  
valves  
Sink  
Standard tub fixture  
Note: Cold water piping to fixtures not shown for clarity purposes.  
Note: This drawing is conceptual in nature and does to address all design, installation or safety considerations.  
Additional safety and/or auxiliary equipment may be needed. This diagram is for reference use by officials, designers and licensed installers.  
It is expected that installers have adequate knowledge of accepted industry practices for the equipment, procedures, and applications involved.  
Drawing is not to scale.  
Drawing # WH1R  
CN  
rev 06/07  
Bosch Water Heating  
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24  
Applications manual  
3.2.3 Bosch ProTankless gas water heater  
Below are two examples of Bosch ProTankless gas water heater  
installations for the whole house. One example shows an Ariston  
mini tank in line for reduced hot water wait time and increased  
temperature stability.  
Bosch GWH 715 ES,  
Bosch GWH C 800 ES,  
Bosch GWH 425 HN or  
Bosch GWH 425 PN  
Hot  
Cold  
Ariston Pro GL4Ti  
for pipe runs over  
100 ft, use GL8Ti  
Note: place Ariston close to the point of  
use to reduce wait time for hot water.  
Bosch GWH 715 ES,  
Bosch GWH C 800 ES,  
Bosch GWH 425 HN or  
Bosch GWH 425 PN  
Symbols  
Standard tub fixture  
Pressure  
relief  
valve  
Cold  
Hot  
Flow  
direction  
Service  
valves  
Sink  
Note: Cold water piping to fixtures not shown for clarity purposes.  
Note: This drawing is conceptual in nature and does not address all design, installation or safety considerations.  
Additional safety and/or auxiliary equipment may be needed. This diagram is for reference use by officials, designers and licensed installers.  
It is expected that installers have adequate knowledge of accepted industry practices for the equipment, procedures, and applications involved.  
Drawing is not to scale.  
Drawing # WH2  
CN  
revA 10/07  
Application manual | 11.2007  
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| 25  
3.2.4 Bosch ProTankless gas water heater with domestic  
recirculation loop  
The circulator should be controlled by an external aquastat, or with  
a timer to run only during times of expected hot water usage.  
Hot  
Cold  
Bosch GWH 715 ES,  
Bosch GWH C 800 ES,  
Bosch GWH 425 HN or  
Bosch GWH 425 PN  
Ariston Pro GL4Ti  
(for pipe runs over  
100ft use GL8Ti)  
Symbols  
Potable water  
expansion tank  
Flow  
check  
valve  
Pressure  
relief  
valve  
Sink  
Standard  
tub  
fixture  
Bronze circulator sized  
Service  
valves  
Timer or  
Aquastat  
Flow direction  
according to UPC standards  
(Taco Bronze 007 or Grundfos 15-42B  
will cover most homes up to 3 bathrooms)  
Note: Cold water piping to fixtures not shown for clarity purposes.  
Note: This drawing is conceptual in nature and does not address all design, installation or safety considerations.  
Additional safety and/or auxiliary equipment may be needed. This diagram is for reference use by officials, designers and licensed installers.  
It is expected that installers have adequate knowledge of accepted industry practices for the equipment, procedures, and applications involved.  
Drawing is not to scale.  
Drawing # WH2R  
CN  
rev 06/07  
Bosch Water Heating  
Applications manual | 11.2007  
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26  
Applications manual  
4 High Volume Potable Water Heating  
Potable water  
Potable water is water that is suitable for drinking. Bosch Water  
Heating appliances are approved to heat potable water only. Heating  
any other liquid other than potable water will void the manfuctures  
warranty covering the appliance.  
Introduction  
This section lays out the options for high volume water heating for  
large residential and light commercial applications including con-  
tinuous ows and high volume demands of large home and  
commercial applications.  
4.1 Parallel unit applications  
Parallel unit applications have twice the activation rate of single unit  
applications. The following designs are for continuous ow, high  
volume hot water needs. Not intended for residential use. To bal-  
ance ows use reverse return piping. (shown below)  
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| 27  
4.1.1 Bosch ProTankless gas water heater in parallel for  
commercial applications  
Two Bosch ProTankless units will have double the activation rate of a  
single unit. When sizing gas line, ensure the gas line is sized to carry  
the BTU load of two units plus any additional gas appliances. See  
the installation manuals for a gas line sizing chart.  
Bosch GWH 715 ES,  
Bosch GWH C 800 ES,  
*see text above about  
activation rate and  
gas supply requirements  
hot  
cold  
hot  
cold  
Symbols  
Pressure  
relief  
valves  
Flow direction  
cold  
hot  
Service  
valves  
Note: This drawing is conceptual in nature and does not address all design, installation or safety considerations.  
Additional safety and/or auxiliary equipment may be needed. This diagram is for reference use by officials, designers and licensed installers.  
It is expected that installers have adequate knowledge of accepted industry practices for the equipment, procedures, and applications involved.  
Drawing is not to scale.  
Drawing # P2  
CN  
revA 10/07  
Bosch Water Heating  
Applications manual | 11.2007  
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28  
Applications manual  
4.2 Cascading unit applications  
A cascading application should be considered if the potential hot  
water demand exceeds the capacity of one GWH 715 ES or  
GWH C 800 ES. The cascading set up supports variable ow inputs  
and is designed for large homes and commercial applications.  
4.2.1 GWH 715 ES and GWH C 800 ES cascading  
Cascading allows up to two appliances to be connected in parallel.  
One of the appliances will serve as the controlling Master appliance  
and will attempt to meet the hot water demand. If the hot water  
demand is beyond the capacity of the Master appliance, a signal is  
sent to the Slave appliance to begin operation.  
Bosch GWH 715 ES or  
Bosch GWH C 800 ES  
• The plumbing must be connected in the reverse  
return method with a minimum number of elbows  
to aid in balancing pressures between the two  
appliances.  
• If a domestic recirculation system is desired,  
recirculate the water through the Ariston ProTi  
water heater as seen in chapter 3.4.  
• Locate appliances close together for  
improved performance.  
tankless link  
hot  
hot  
cold  
cold  
• Follow industry plumbing practices when installing  
multiple appliances  
• Minimum pipe diameter: ¾"  
• Minimum water pressure: 50 psi  
• Maximum distance between appliances: 36"  
• Insulate pipes to prevent heat loss.  
Symbols  
cold  
hot  
Flow direction  
inlet  
outlet  
Water  
hammer  
arrestor  
Pressure  
relief  
valve  
Ariston Pro GL8Ti  
recommended  
Service  
valves  
Tankless  
link  
Note: This drawing is conceptual in nature and does not address all design, installation or safety considerations.  
Additional safety and/or auxiliary equipment may be needed. This diagram is for reference use by officials, designers and licensed installers.  
It is expected that installers have adequate knowledge of accepted industry practices for the equipment, procedures, and applications involved.  
Drawing is not to scale.  
Drawing # CA1  
CN  
revA 10/07  
Application manual | 11.2007  
Bosch Water Heating  
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| 29  
4.3 External storage tank loading applications.  
Introduction  
This section lays out tank loading options for high volume water  
heating for large residential and light commercial applications  
including continuous ows and high volume demands of large home  
and commercial applications.  
4.3.1 GWH 345/450 ESR pressure drops and circulator guidelines  
The maximum amp draw for any circulator connected directly to  
the appliance must not exceed 1.5 amps  
Circulator should be sized by the professional plumbing  
contractor  
Bronze or stainless steel circulators required for all open loop  
applications  
50 feet of head  
40 feet of head  
30 feet of head  
GWH 345 ESR  
20 feet of head  
10 feet of head  
0 feet of head  
0 GPM  
1 GPM  
2 GPM  
3 GPM  
4 GPM  
5 GPM  
6 GPM  
water flow rate  
50 feet of head  
40 feet of head  
30 feet of head  
20 feet of head  
10 feet of head  
0 feet of head  
GWH 450 ESR  
0 GPM  
1 GPM  
2 GPM  
3 GPM  
4 GPM  
5 GPM  
6 GPM  
water flow rate  
Pressure drop curves  
Note : Flow above 6 GPM is not permitted.  
Bosch Water Heating  
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Applications manual  
4.3.2 Single unit tank loading application plumbing diagram  
The GWH 345/450 ESR is specically designed for this application.  
Cold water  
DHW  
feed  
Bosch GWH 345 ESR,  
Bosch GWH 450 ESR  
PS  
Symbols  
External  
storage  
tank  
Potable water  
expansion tank  
Pressure  
relief  
valve  
Flow  
direction  
Bronze circulator sized  
according to UPC standards  
12K ohm  
thermistor  
with immersion  
well  
Service  
valves  
Note: Piping to fixtures not shown for clarity purposes.  
Note: This drawing is conceptual in nature and does not address all design, installation or safety considerations.  
Additional safety and/or auxiliary equipment may be needed. This diagram is for reference use by officials, designers and licensed installers.  
It is expected that installers have adequate knowledge of accepted industry practices for the equipment, procedures, and applications involved.  
Drawing is not to scale.  
Drawing # STL  
CN  
revA 10/07  
Application manual | 11.2007  
Bosch Water Heating  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Applications manual  
| 31  
4.3.2 Single unit tank loading application electrical diagram  
The following shows the appropriate electrical connections for  
plumbing diagram 4.3.2  
Terminal box  
110VAC from outlet  
PK P0 PS PE  
L
N
LL  
N
L
ESR control  
board  
PS  
PCB  
Single Unit Tank Loading  
Electrical Diagram  
Note: This drawing is conceptual in nature and does not address all design, installation or safety considerations.  
Additional safety and/or auxiliary equipment may be needed. This diagram is for reference use by officials, designers and licensed installers.  
It is expected that installers have adequate knowledge of accepted industry practices for the equipment, procedures, and applications involved.  
Drawing is not to scale.  
Drawing # ESTL  
CN  
revA 10/07  
Bosch Water Heating  
Applications manual | 11.2007  
Download from Www.Somanuals.com. All Manuals Search And Download.  
|
32  
Applications manual  
5 Open Loop Space Heating  
5.1 External storage tank  
Introduction  
This section is designed to provide a road map of techniques for  
using a tankless water heater to heat domestic water and at the  
same time provide space heating in residential applications. As with  
all installations, check with the local authority having jurisdiction.  
Some jurisdictions may not allow these types of applications.  
The appliances shown in this section are approved under ANSI  
Z21.10.3 and CSA 4.3 as circulating gas water heaters. Only open  
loop applications are approved under this standard.  
5.1.1 Radiant space heating and DHW plumbing diagram  
Bosch GWH 345 ESR,  
Bosch GWH 450 ESR  
DHW  
Cold water  
feed  
P2  
P1  
PS  
Symbols  
Storage  
tank  
Radiant  
piping  
Potable water  
expansion tank  
Flow  
direction  
Pressure  
relief  
valve  
Bronze circulator  
sized according to  
UPC standards  
12K ohm  
thermistor  
with immersion  
well  
Thermossttatic  
mixing  
vallvee  
Service  
valves  
Note: Piping to fixtures not shown for clarity purposes.  
Note: This drawing is conceptual in nature and does not address all design, installation or safety considerations.  
Additional safety and/or auxiliary equipment may be needed. This diagram is for reference use by officials, designers and licensed installers.  
It is expected that installers have adequate knowledge of accepted industry practices for the equipment, procedures, and applications involved.  
Drawing is not to scale.  
Drawing # ROL  
CN  
revA 10/07  
Application manual | 11.2007  
Bosch Water Heating  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Applications manual  
| 33  
5.1.1 Radiant space heating and DHW electrical diagram  
The following shows the appropriate electrical connections for  
plumbing diagram 5.1.1  
Terminal box  
110VAC from outlet  
PK P0 PS PE  
L
N
LL  
N
L
ESR control  
board  
PS  
PCB  
T
Stat  
T
Stat  
24 VAC  
POWER  
ZONE1 ZONE2  
TWO ZONE SWITCHING RELAY  
SR 502  
FUSE 1 AMP  
X2  
N
P
ZC  
H
X1 ZR  
ZONE1 ZONE2  
Neutral  
120Vac  
P1  
P2  
Radiant Space Heating and DHW  
Electrical Diagram  
Note: This drawing is conceptual in nature and does not address all design, installation or safety considerations.  
Additional safety and/or auxiliary equipment may be needed. This diagram is for reference use by officials, designers and licensed installers.  
It is expected that installers have adequate knowledge of accepted industry practices for the equipment, procedures, and applications involved.  
Drawing is not to scale.  
Drawing # EROL  
CN  
revA 10/07  
Bosch Water Heating  
Applications manual | 11.2007  
Download from Www.Somanuals.com. All Manuals Search And Download.  
|
34  
Applications manual  
5.1.2 Fan coil space heating and DHW plumbing diagram  
Bosch GWH 345 ESR,  
Bosch GWH 450 ESR  
DHW  
Cold water  
feed  
Fan Coil  
P1  
PK  
Symbols  
Potable water  
expansion tank  
Flow  
check  
valve  
Storage  
tank  
Fan Coil  
Pressure  
relief  
valve  
Air  
seperator  
Bronze circulator  
sized according to  
UPC standards  
Thermostatic  
mixing  
valve  
Service  
valves  
Flow  
direction  
Tank  
Aquastat  
Note: Piping to fixtures not shown for clarity purposes.  
Note: This drawing is conceptual in nature and does to address all design, installation or safety considerations.  
Additional safety and/or auxiliary equipment may be needed. This diagram is for reference use by officials, designers and licensed installers.  
It is expected that installers have adequate knowledge of accepted industry practices for the equipment, procedures, and applications involved.  
Drawing is not to scale.  
Drawing # FCOL  
CN  
revA 10/07  
Application manual | 11.2007  
Bosch Water Heating  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Applications manual  
| 35  
5.1.2 Fan Coil space heating and DHW electrical diagram  
The following shows the appropriate electrical connections for plumbing diagram 5.1.2  
Terminal box  
110VAC from outlet  
PK P0 PS PE  
L
N
LL  
N
L
ESR control  
board  
PK  
T
Stat  
SR501  
24  
TT  
1 ZONE  
R
T
W
T
VAC  
SWITCHING RELAY  
COM  
LR  
LS  
120 VAC  
INPUT  
4
4
6
6
N
H
3
5
N/O  
N/C  
N/C  
N/O  
Neutral  
120Vac  
AQUASTAT  
P1  
Fan Coil Space Heating and DHW  
Electrical Diagram  
Note: This drawing is conceptual in nature and does not address all design, installation or safety considerations.  
Additional safety and/or auxiliary equipment may be needed. This diagram is for reference use by officials, designers and licensed installers.  
It is expected that installers have adequate knowledge of accepted industry practices for the equipment, procedures, and applications involved.  
Drawing is not to scale.  
Drawing # EFCOL  
CN  
revA 10/07  
Bosch Water Heating  
Applications manual | 11.2007  
Download from Www.Somanuals.com. All Manuals Search And Download.  
|
36  
Applications manual  
5.1.3 Baseboard/ Radiant Panel space heating and DHW plumbing diagram  
Bosch GWH 345 ESR,  
Bosch GWH 450 ESR  
DHW  
Cold water  
feed  
P1  
PK  
Symbols  
Potable water  
Flow  
Flow  
direction  
Storage  
tank  
Baseboard/  
Radiant  
Panel  
expansion tank  
check  
valve  
Pressure  
relief  
valve  
Air  
seperator  
Tank  
Aquastat  
Bronze circulator  
sized according to  
UPC standards  
Thermostatic  
Mixing  
valve  
Service  
valves  
Note: Piping to fixtures not shown for clarity purposes.  
Note: This drawing is conceptual in nature and does not address all design, installation or safety considerations.  
Additional safety and/or auxiliary equipment may be needed. This diagram is for reference use by officials, designers and licensed installers.  
It is expected that installers have adequate knowledge of accepted industry practices for the equipment, procedures, and applications involved.  
Drawing is not to scale.  
Drawing # BB  
OL  
CN  
revA 10/07  
Application manual | 11.2007  
Bosch Water Heating  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Applications manual  
| 37  
5.1.3 Baseboard/Radiant Panel space heating and DHW electrical diagram  
The following shows the appropriate electrical connections for plumbing diagram 5.1.3  
Terminal box  
110VAC from outlet  
PK P0 PS PE  
L
N
LL  
N
L
ESR control  
board  
PK  
T
Stat  
24 VAC  
POWER  
TT  
ZONE1 ZONE2 ZONE3  
THREE ZONE SWITCHING RELAY  
WITH OPTIONAL PRIORITY  
SR 503  
or equivalent  
LR  
LS  
FUSE 1 AMP  
X2  
N
P
ZC  
H
X1 ZR  
ZONE1 ZONE2 ZONE3  
Neutral  
120Vac  
AQUASTAT  
P1  
Baseboard Space Heating and DHW  
Electrical Diagram  
Note: This drawing is conceptual in nature and does not purport to address all design, installation or safety considerations.  
Additional safety and/or auxiliary equipment may be needed. This diagram is for reference use by officials, designers and licensed installers.  
It is expected that installers have adequate knowledge of accepted industry practices for the equipment, procedures, and applications involved.  
Drawing is not to scale.  
Drawing # EBBOL  
CN  
revA 10/07  
Bosch Water Heating  
Applications manual | 11.2007  
Download from Www.Somanuals.com. All Manuals Search And Download.  
|
38  
Applications manual  
5.1.4 Baseboard/ Radiant Panel space heating and DHW (with Ariston mini tank) plumbing diagram  
Bosch GWH 345 ESR,  
Bosch GWH 450 ESR  
PK  
PS  
Cold waterfeed  
Aquastat  
well with  
12k ohm  
DHW  
thermistor  
(insulate piping  
around thermistor)  
Cold water  
feed  
Symbols  
Baseboard/  
Radiant  
Panel  
Flow  
check  
valve  
Potable  
water  
expansion tank  
Ariston GL8Ti  
mini water  
tank  
Pressure  
relief  
valve  
Aquastat  
well & 12kohm  
thermistor  
Bronze circulator  
sized according to  
UPC standards  
Thermostatic  
mixing  
valve  
Service  
valves  
Flow  
direction  
Note: Piping to fixtures not shown for clarity purposes.  
Note: This drawing is conceptual in nature and does not address all design, installation or safety considerations.  
Additional safety and/or auxiliary equipment may be needed. This diagram is for reference use by officials, designers and licensed installers.  
It is expected that installers have adequate knowledge of accepted industry practices for the equipment, procedures, and applications involved.  
Drawing is not to scale.  
Drawing # BBAOL  
CN  
revA 10/07  
Application manual | 11.2007  
Bosch Water Heating  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Applications manual  
| 39  
5.1.4 Baseboard/Radiant Panel space heating and DHW (with Ariston mini tank) electrical diagram  
The following shows the appropriate electrical connections for plumbing diagram 5.1.4  
Terminal box  
110VAC from outlet  
PK P0 PS PE  
L
N
LL  
N
L
ESR control  
board  
PK  
PS  
PCB  
TT  
LR  
LS  
Room Thermostat  
Baseboard/Radiant Panel Space Heating and DHW (with Ariston mini tank)  
Electrical Diagram  
Note: This drawing is conceptual in nature and does not address all design, installation or safety considerations.  
Additional safety and/or auxiliary equipment may be needed. This diagram is for reference use by officials, designers and licensed installers.  
It is expected that installers have adequate knowledge of accepted industry practices for the equipment, procedures, and applications involved.  
Drawing is not to scale.  
Drawing # EBBAOL  
CN  
revA 10/07  
Bosch Water Heating  
Applications manual | 11.2007  
Download from Www.Somanuals.com. All Manuals Search And Download.  
|
40  
Applications manual  
5.1.5 Baseboard/ Radiant Panel space heating and DHW (without storage tank) plumbing diagram  
Bosch GWH 345 ESR,  
Bosch GWH 450 ESR  
PK  
Insulate  
piping  
DHW  
PS  
Cold water  
feed  
Symbols  
Baseboard/  
Radiant  
Panel  
Flow  
check  
valve  
Flow  
direction  
Piping  
Insulation  
Aquastat  
well & 12kohm  
thermistor  
Pressure  
relief  
valve  
Bronze circulator  
sized according to  
UPC standards  
Service  
valves  
Thermostatic  
mixing  
valve  
Note: Piping to fixtures not shown for clarity purposes.  
Note: This drawing is conceptual in nature and does not address all design, installation or safety considerations.  
Additional safety and/or auxiliary equipment may be needed. This diagram is for reference use by officials, designers and licensed installers.  
It is expected that installers have adequate knowledge of accepted industry practices for the equipment, procedures, and applications involved.  
Drawing is not to scale.  
Drawing # BBNTOL  
CN  
revA 10/07  
Application manual | 11.2007  
Bosch Water Heating  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Applications manual  
| 41  
5.1.5 Baseboard/Radiant Panel space heating and DHW (without storage tank) electrical diagram  
The following shows the appropriate electrical connections for plumbing diagram 5.1.5  
Terminal box  
110VAC from outlet  
PK P0 PS PE  
L
N
LL  
N
L
ESR control  
board  
PK  
PS  
PCB  
Baseboard/Radiant Panel Space Heating and DHW  
Without Storage Tank Electrical Diagram  
Note: This drawing is conceptual in nature and does not address all design, installation or safety considerations.  
Additional safety and/or auxiliary equipment may be needed. This diagram is for reference use by officials, designers and licensed installers.  
It is expected that installers have adequate knowledge of accepted industry practices for the equipment, procedures, and applications involved.  
Drawing is not to scale.  
Drawing # BBNTOL  
CN  
revA 10/07  
Bosch Water Heating  
Applications manual | 11.2007  
Download from Www.Somanuals.com. All Manuals Search And Download.  
|
42  
Applications manual  
5.2 Indirect Tank Applications  
5.2.1 Indirect Baseboard/ Radiant Panel space heating and DHW plumbing diagram  
Note: Not suitable for space heating applications requiring high water temperature.  
Bosch GWH 345 ESR,  
Bosch GWH 450 ESR  
Cold water  
feed  
DHW  
P1  
Cold  
feed  
PK  
Symbols  
Potable water  
expansion tank  
Baseboard/  
Radiant  
Panel  
Flow  
Flow  
Indirect  
hot water  
tank  
direction  
check  
valve  
Pressure  
relief  
valve  
Tank  
Aquastat  
Air  
seperator  
Bronze circulator  
sized according to  
UPC standards  
Pressure  
reducing  
valve  
Thermostatic  
Mixing  
valve  
Service  
valves  
Back Flow  
preventer  
Note: Piping to fixtures not shown for clarity purposes.  
Note: This drawing is conceptual in nature and does not address all design, installation or safety considerations.  
Additional safety and/or auxiliary equipment may be needed. This diagram is for reference use by officials, designers and licensed installers.  
It is expected that installers have adequate knowledge of accepted industry practices for the equipment, procedures, and applications involved.  
Drawing is not to scale.  
Drawing # IDBBOL  
CN  
revA 10/07  
Application manual | 11.2007  
Bosch Water Heating  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Applications manual  
| 43  
5.2.1 Baseboard/Radiant Panel space heating and DHW electrical diagram  
The following shows the appropriate electrical connections for plumbing diagram 5.2.1  
Terminal box  
110VAC from outlet  
PK P0 PS PE  
L
N
LL  
N
L
ESR control  
board  
PK  
T
Stat  
24 VAC  
POWER  
TT  
ZONE1 ZONE2 ZONE3  
THREE ZONE SWITCHING RELAY  
WITH OPTIONAL PRIORITY  
SR 503  
or equivalent  
LR  
LS  
FUSE 1 AMP  
X2  
N
P
ZC  
H
X1 ZR  
ZONE1 ZONE2 ZONE3  
Neutral  
120Vac  
AQUASTAT  
P1  
Indirect Baseboard/Radiant Panel Space Heating and DHW  
Electrical Diagram  
Note: This drawing is conceptual in nature and does not address all design, installation or safety considerations.  
Additional safety and/or auxiliary equipment may be needed. This diagram is for reference use by officials, designers and licensed installers.  
It is expected that installers have adequate knowledge of accepted industry practices for the equipment, procedures, and applications involved.  
Drawing is not to scale.  
Drawing # EID BBOL  
CN  
revA 10/07  
Bosch Water Heating  
Applications manual | 11.2007  
Download from Www.Somanuals.com. All Manuals Search And Download.  
|
44  
Applications manual  
6 Maintenance Drawings  
Bosch appliances are designed to last for many years. In order to keep the heater operating properly, periodic maintenance is required.  
Please consult the installation manual for maintenance intervals. A descaling procedure drawing is included to assist in clearing the water  
heater of mineral deposits that may build up over time.  
6.1 Descaling procedure  
This procedure should only be done if there is evidence of scale build-up such as a reduced hot water ow rate or if the water is known to  
have high levels of minerals such as calcium.  
1. Disconnect electrical supply from the water heater.  
2. Shut off the water supply to the water heater using (installer supplied) isolation 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.  
5. Connect the line (A) from the outlet of the circulating pump (installer supplied) to the inlet water tting on the water heater.  
6. Using another line (B), connect to the water outlet tting on the water heater. Route the other end of this line into a descaling reser-  
voir.  
7. Using a 3rd line (C) from the descaling reservoir, connect to the inlet side of circulating pump. Verify there is a lter on the end of the  
line in the descaling reservoir.  
8. Make sure all connections are “hand tight.”  
9. Fill tank with descaling solution so lines inside are submersed. We recommend a straight white vinegar. If using a commercial descalant,  
refer to manufacturer’s instructions for proper dilution ratio.  
11. Operate the circulating pump.  
12. Make sure there are no leaks and the solution is owing from the descaling reservoir through the heat exchanger and returning to the  
reservoir.  
13. Run solution through the heat exchanger until the solution returning to the descaling reservoir comes out clear. (Changing to a fresh  
solution may be necessary during this process)  
14. Disconnect all lines and drain all solution from heat exchanger. Properly discard of solution.  
15. Position a container below the hot water outlet and connect cold water supply. Open cold water supply isolation valve and ush heat  
exchanger with clean water.  
16. Shut cold water isolation valve and reconnect hot water supply to the water heater.  
17. Reconnect electrical supply to unit, open water isolation valves, and return the unit to service.  
Application manual | 11.2007  
Bosch Water Heating  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Applications manual  
| 45  
6.1 Descaling procedure diagram  
Bosch GWH 715 ES,  
Bosch GWH C 800 ES,  
Bosch GWH 425 HN or  
Bosch GWH 425 PN  
Symbols  
Circulating  
pump  
B
Flow direction  
Filter  
C
A
Service  
valves  
Note: This drawing is conceptual in nature and does not purport to address all design, installation or safety considerations.  
Additional safety and/or auxiliary equipment may be needed. This diagram is for reference use by officials, designers and licensed installers.  
It is expected that installers have adequate knowledge of accepted industry practices for the equipment, procedures, and applications involved.  
Drawing is not to scale.  
Drawing # MD1  
CN  
revA 10/07  
Bosch Water Heating  
Applications manual | 11.2007  
Download from Www.Somanuals.com. All Manuals Search And Download.  
|
46  
Applications manual  
Application manual | 11.2007  
Bosch Water Heating  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Applications manual  
| 47  
Bosch Water Heating  
Applications manual | 11.2007  
Download from Www.Somanuals.com. All Manuals Search And Download.  
|
48  
Applications manual  
Application manual | 11.2007  
Bosch Water Heating  
Download from Www.Somanuals.com. All Manuals Search And Download.  
Applications manual  
| 49  
Bosch Water Heating  
Applications manual | 11.2007  
Download from Www.Somanuals.com. All Manuals Search And Download.  
BBT North America Corporation  
Bosch Group  
Bosch Water Heating  
50 Wentworth Ave  
Londonderry, NH 03053  
Telephone (603) 882-1100  
Fax (603) 584-1681  
Download from Www.Somanuals.com. All Manuals Search And Download.  

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