Part #473501
ERCH-HP Energy Recovery Ventilator
with Heat Pump
®
Installation, Operation and Maintenance Manual
Please read and save these instructions. Read carefully before attempting to assemble, install, operate or maintain the
product described. Protect yourself and others by observing all safety information. Failure to comply with instructions could
result in personal injury and/or property damage! Retain instructions for future reference.
Model ERCH-HP
General Safety Information
Only qualified personnel should install this system.
Personnel should have a clear understanding of these
DANGER
• Always disconnect power before working on or near
this equipment. Lock and tag the disconnect switch
or breaker to prevent accidental power up.
instructions and should be aware of general safety
precautions. Improper installation can result in electric
shock, possible injury due to coming in contact with
moving parts, as well as other potential hazards,
including environmental. Other considerations may be
required if high winds or seismic activity are present.
If more information is needed, contact a licensed
professional engineer before moving forward.
• If this unit is equipped with optional gas
accessories, turn off gas supply whenever power is
disconnected.
CAUTION
This unit is equipped with a compressed refrigerant
system. If a leak in the system should occur,
immediately evacuate and ventilate the area. An EPA
Certified Technician must be engaged to make repairs
or corrections. Refrigerant leaks may also cause
bodily harm.
1. Follow all local electrical and safety codes, as well
as the National Electrical Code (NEC), the National
Fire Protection Agency (NFPA), where applicable.
Follow the Canadian Electric Code (CEC) in
Canada.
2. All moving parts must be free to rotate without
striking or rubbing any stationary objects.
CAUTION
3. Unit must be securely and adequately grounded.
When servicing the unit, the internal components may
be hot enough to cause pain or injury. Allow time for
cooling before servicing.
4. Do not spin fan wheel faster than maximum
cataloged fan RPM. Adjustments to fan speed
significantly affect motor load. If the fan RPM is
changed, the motor current should be checked to
make sure it is not exceeding the motor nameplate
amps.
5. Verify that the power source is compatible with the
equipment.
6. Never open access doors to the unit while it is
running.
Model ERCH-HP Energy Recovery Unit
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1
Table of Contents
General Safety Information . . . . . . . . . . . . . . . . . . . .1
Receiving, Handling and Storage . . . . . . . . . . . . . . .2
Product Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Models and Capacities . . . . . . . . . . . . . . . . . . . . . . . .4
Subassemblies
Coils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Dampers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Energy Wheel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Heat Pump Module . . . . . . . . . . . . . . . . . . . . . . . . . .6
Optional Electric Heaters. . . . . . . . . . . . . . . . . . . . . .6
Optional Indirect Gas Furnace. . . . . . . . . . . . . . . . . .6
Installation
Dimensional Data. . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Unit Weights and Recommended Roof Opening . . .7
Service Clearances . . . . . . . . . . . . . . . . . . . . . . . . . .8
Handling, Lifting and Lifting Lugs . . . . . . . . . . . . . . .9
Roof Curb Mounting, Dimensions, Weights . . . . . .10
Ductwork Connections . . . . . . . . . . . . . . . . . . . . . .11
Rail Mounting / Layout. . . . . . . . . . . . . . . . . . . . . . .11
Exhaust Weatherhood . . . . . . . . . . . . . . . . . . . . . . .11
Start-Up Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Pre-Start-Up Checklist. . . . . . . . . . . . . . . . . . . . . . .13
Start-Up Procedure . . . . . . . . . . . . . . . . . . . . . . . . .13
Voltage Imbalance . . . . . . . . . . . . . . . . . . . . . . . . . .13
Unit Start-Up Checklist . . . . . . . . . . . . . . . . . . . . . .14
Electrical Information
Energy Wheel
Start-Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Sequence of Operation . . . . . . . . . . . . . . . . . . . . . .22
Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Heat Pump Overview
Heat Pump Components . . . . . . . . . . . . . . . . . . . . .24
Heat Pump Controls . . . . . . . . . . . . . . . . . . . . . . . .25
Refrigeration Schematic. . . . . . . . . . . . . . . . . . . . . .26
Typical Operating Conditions. . . . . . . . . . . . . . . . . .26
Unit Protection Module Fault Indicators . . . . . . . . .27
Troubleshooting
Controller Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . .28
Airflow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
Unit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
Refrigeration Circuit . . . . . . . . . . . . . . . . . . . . . . 31-35
Maintenance
Monthly, Semianually, Annually . . . . . . . . . . . . . . . .36
Heat Pump. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36
Maintenance Procedures
Lubrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36
Dampers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36
Fan Belts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36-37
Fan Motors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37
Fan Wheel and Fasteners . . . . . . . . . . . . . . . . . . . .37
Fan Bearings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37
Internal Filter Maintenance . . . . . . . . . . . . . . . . . . .38
External Filter Maintenance . . . . . . . . . . . . . . . . . . .38
Coil Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . .38
Maintenance Log. . . . . . . . . . . . . . . . . . . . . . . . . . . .39
Warranty. . . . . . . . . . . . . . . . . . . . . . . . . . . . Backcover
General Electrical Information . . . . . . . . . . . . . . . . .15
Discharge Air Temp Sensor . . . . . . . . . . . . . . . . . . .16
Plumbing/Piping Overview
Condensate Drain Trap . . . . . . . . . . . . . . . . . . . . . .16
Optional Remote Control Panel and
Wiring Schematics. . . . . . . . . . . . . . . . . . . . . . . . .17
Typical Control Center Components. . . . . . . . . . . .18
Electrical Controls
Optional Frost Control . . . . . . . . . . . . . . . . . . . . . . .19
Optional Economizer . . . . . . . . . . . . . . . . . . . . . . . .20
Phase Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
Variable Frequency Drive . . . . . . . . . . . . . . . . . . . . .20
Optional Rotation Sensor. . . . . . . . . . . . . . . . . . . . .21
Dirty Filter Sensor . . . . . . . . . . . . . . . . . . . . . . . . . .21
Model ERCH-HP Energy Recovery Unit
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Product Overview
Models and Capacities
This unit brings in fresh, outdoor air and removes
stale exhaust air from the building. The intake and
exhaust airstreams move through the unit in opposite
directions in separate passages, and each airstream
passes through an energy wheel. In cooling mode, the
energy wheel removes both heat and moisture from
the incoming airstream and rejects it into the exhaust
airstream. In heating mode, the energy wheel removes
heat and humidity from the exhaust air and rejects
it into the intake air, thus reclaiming energy already
expended to heat the building air.
This unit is manufactured in four different platform sizes;
20, 45, 55 and 90. Each platform has multiple options
for heating and cooling capacities.
All 4, 5 and 6 ton capacity units have a single scroll
type compressor and all other units have two scroll type
compressors and use a split airside heat pump coil.
Heat Pump Capacity
Unit Size
Tons
ERCH-HP 20 4, 5, 6
ERCH-HP 45 8, 10, 12.5, 15
ERCH-HP 55 15, 17.5, 20
ERCH-HP 90 20, 25, 30
In addition to the energy wheel, this unit incorporates
a packaged water source heat pump The heat pump
system comes from the factory fully-charged with
refrigerant and is ready for connection to a water source
upon arrival.
For purposes of providing temporary emergency heat,
an optional secondary heating source such as indirect
gas furnace or electric heaters may also be installed.
The smaller tonnage units (4-6 tons) contain a single
compressor, allowing for one stage of cooling. Larger
units (8-30 tons) come standard with two compressors
and a split airside coil. This allows for staging of
compressors to meet a wider range of outdoor air loads
while reducing the amount of cycles per compressor.
Simply put, this unit preconditions the outdoor air to
save money on heating and cooling costs and then
provides supplemental heating and cooling by means
of a highly efficient heat pump.
Heat Pump
Airside Heating
and Cooling Coil
Heat Pump
Compressor(s)
Heat Pump Module
(component locations
will vary)
Outdoor
Air Intake
Filters
Energy Wheel
Cassette
Coaxial
Refrigerant-to-Water
Heat Exchanger
Reheat
Coil
Supply Air
Motor & Blower
Model ERCH-HP Energy Recovery Unit
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4
Subassemblies
Coils
Energy Wheel
The airside coil is connected to the heat pump
compressor(s) and is the primary vehicle for heating
and cooling of the building. A reheat coil is optionally
available and is installed in the supply airstream
adjacent to the airside coil. The reheat coil is also
connected to the heat pump but is used only when the
unit is in cooling mode.
The energy wheel rotates through both the outdoor air
and the exhaust airstreams, removing both sensible
(heat) energy and latent moisture from one airstream
and transferring it to the other airstream. The energy
wheel itself is comprised of segments which can be
removed for servicing.
Bearing Support
Adjustable
Air Seals
Label showing
cassette serial number
and date code
Heat Pump
Airside Coil
Drive Belt
Optional Heat Pump
Reheat Coil
Drive Pulley
Dampers
Filters
There are four locations where dampers are optionally
installed.
There are three locations in the unit where filters will be
found.
Gravity Type
Exhaust Damper
Motorized Exhaust
Air Damper
Two-inch thick MERV 8
Exhaust
Hood
pleated filters
Exhaust
Hood
Electrical Box
Electrical Box
Exhaust Air
Intake
Exhaust Air
Intake
Two-inch thick MERV 8 or
MERV 13 pleated filters
Motorized Outdoor
Air Intake Damper
Motorized Recirculating Air
Damper
Permanent Metal Filters
Model ERCH-HP Energy Recovery Unit
5
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Heat Pump Module
Optional Electric Heaters
Every unit has an integral heat pump module that
contains hermetic scroll-type compressor(s), a coaxial
refrigerant-to-water heat exchanger(s), refrigerant flow
reversing valve(s), expansion valve(s), liquid line filter
drier, high pressure manual reset cutout, crankcase
heater(s) and various sensors, service ports and safety
devices which allows the unit to run at less than full
capacity and results in fewer compressor cycles. The
heat pump is intended to be connected to an external
water source such as a water cooling tower or boiler, a
geothermal source or even a ground loop. The module
is piped to the airside coil located in the intake airstream
and optionally to a reheat coil that will control humidity.
The location of components in the module will
vary.
There are two optional electric heaters available. One is
a preheater and is used to prevent frost buildup on the
energy wheel. It is located directly in front of the intake
air filter assembly. The second optional heater is used
as a supplementary emergency heat source for the
building and is integrated into the supply airstream.
Optional Electric
Optional Electric
Preheater Location
Heater Location
Control circuitry and the Unit Protection Module (UPM)
for the heat pump module are located in the heat pump
module. The UPM is a
printed circuit board and
has LED fault indicator
lights to indicate various
Supply Air Motor and
Blower Assembly
alarm conditions and also
power status. A unit-
specific schematic for
electrical circuits is located
in the control center and
another unit-specific
schematic for heat pump
Optional Indirect Gas Furnace
An optional indirect gas furnace may be installed and
provides supplementary emergency heat to the building.
A complete Installation, Operation and Maintenance
Manual for the furnace is provided with the unit. A unit-
specific wiring diagram is located inside the furnace
housing access door.
Unit Protection Module
(UPM)
circuitry is located in the heat pump module.
Refrigerant
High Efficiency
Reversing
Scroll Type
Valves
Compressors
Indirect Gas Furnace
Coaxial
Refrigerant-
to-Water Heat
Exchangers
Water Intake
and Discharge
Connections
Heat Pump Module
Model ERCH-HP Energy Recovery Unit
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6
Installation
Dimensional Data
Overall Exterior Dimensions
Model
Width
Overall Width
Overall Length
(including Lifting Lugs)
(with Exhaust Hood)
(with Outdoor Air Hood)
ERCH-HP 20
ERCH-HP 45
ERCH-HP 55
ERCH-HP 90
59.5
69.5
79.5
99.5
75
86
116
122
134
147
101
123
All dimensions shown are in inches.
Unit Weights and Recommended Roof Opening
V
Exhaust
Intake
U
Supply
Discharge
1/2 inch
1/2 inch
1/2 inch
Approximate
Weight (pounds)
Unit Size
U
V
ERCH-HP 20
ERCH-HP 45
ERCH-HP 55
ERCH-HP 90
46
54
65
85
37
39
47
49
2150
3500
4450
5300
All dimensions are in inches. Unit weights assume rooftop
configuration with weatherhoods, filters, outdoor air damper,
six row DX coil, integral condensing section and an indirect
gas-fired furnace.
Position the unit roof opening such that the supply
discharge and exhaust inlet of the unit will line up with
the corresponding ductwork. Be sure to allow for the
recommended service clearances when positioning
opening (see Service Clearances). Do not face the
outdoor air intake of the unit into prevailing wind and
keep the intake away from any other exhaust fans.
Likewise, position the exhaust discharge opening away
from outdoor air intakes of any other equipment.
Model ERCH-HP Energy Recovery Unit
7
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Service Clearances
Minimum clearances are required for access on all sides for routine maintenance. Filter replacement, drain pan
inspection and cleaning, energy wheel cassette inspection, fan bearing lubrication and belt adjustment are examples
of routine maintenance that must be performed. Blower and motor assemblies, energy wheel cassette, coil and filter
sections are always provided with a service door or panel for proper component access. Clearances for component
removal may be greater than the service clearances, refer to drawings for these dimensions.
ERCH-HP 20
ERCH-HP 45
36 IN
EXHAUST
HOOD
ACCESS PANEL
ACCESS PANEL
ELECTRICAL BOX
36 IN
EXHAUST AIR
INTAKE
36 IN
MINIMUM
52 IN
ACCESS PANEL
CLEARANCE
WITH IG HEATER
ACCESS PANEL
*48 IN
**64 IN
Clearances for service and component removal on ERCH-HP 20 and ERCH-HP 45
* Clearance for energy wheel removal on ERCH-HP 20
** Clearance for energy wheel removal on ERCH-HP 45
ERCH-HP 55
ERCH-HP 90
42 IN
EXHAUST
HOOD
ACCESS PANEL
ACCESS PANEL
ELECTRICAL BOX
42 IN
EXHAUST AIR
INTAKE
36 IN
MINIMUM
52 IN
ACCESS PANEL
CLEARANCE
WITH IG HEATER
ACCESS PANEL
42 IN
Clearances for service and component removal on ERCH-HP 55 and ERCH-HP 90
Model ERCH-HP Energy Recovery Unit
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8
Handling
While this unit was constructed with quality and
dependability in mind, damage still may occur during
handling of the unit for installation. Exercise extreme
caution to prevent any damage from occurring to
the refrigerant system. This unit contains a system
pressurized with refrigerant that, if damaged, could
leak into the atmosphere or cause bodily harm due to
the extreme cold nature of expanding refrigerant. Use
protective equipment such as gloves and safety glasses
to minimize or prevent injury in case of a system leak
during installation.
WARNING
All factory provided lifting lugs must be used when
lifting the units. Failure to comply with this safety
precaution could result in property damage, serious
injury, or death. Unit weights assume rooftop
configuration with weatherhoods, filters, outdoor air
damper, six row DX coil, integral condensing section
and an indirect gas fired furnace.
Lifting Lugs
NOTE
The system design and installation should follow
accepted industry practice, such as described in
the ASHRAE Handbook. Adequate space should be
left around the unit for piping coils and drains, filter
replacement, and maintenance. Sufficient space should
be provided on the side of the unit for routine service
and component removal should that become necessary.
On some models, one lifting lug may be positioned
directly in front of the condensate drain connection.
Any lifting lug that is located as shown should be
removed in order to permit installation of the P trap
drain kit.
Lifting
1. Before lifting, be sure that all shipping material has
been removed from unit.
2. To assist in determining rigging requirements,
weights are provided in the Installation, Unit
Weights and Recommended Roof Opening section
of this manual.
3. Unit must be lifted by all lifting lugs provided on
base structure.
4. Rigger to use suitable mating hardware to attach to
unit lifting lugs.
5. Spreader bar(s) must span the unit to prevent
damage to the cabinet by the lift cables.
6. Always test-lift the unit to check for proper balance
and rigging before hoisting to desired location.
7. Never lift units by weatherhoods.
8. Never lift units in windy conditions.
9. Preparation of curb and roof openings should be
completed prior to lifting unit to the roof.
10. Check to be sure that gasketing (supplied by
others) has been applied to the curb prior to lifting
the unit and setting on curb.
11. Do not use fork lifts for handling unit.
Model ERCH-HP Energy Recovery Unit
9
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Roof Curb Mounting
Curb Outside Dimensions and Weights
Rooftop units require curbs to be mounted first. The
duct connections must be located so they will be clear
of structural members of the building.
SIDE OF UNIT
BASE
A
Factory Supplied Roof Curbs: Roof curbs are Model
GKD, which are shipped in a knockdown kit (includes
duct adapter) and require field assembly (by others).
Assembly instructions are included with the curb.
B
C
D
E
1 INCH INSULATION
Install Curb: Locate curb over roof opening and
fasten in place. Reference Installation, Unit Weights
and Recommended Roof Openings in this manual.
Check that the diagonal dimensions are within 1/8
inch of each other and adjust as necessary. For proper
coil drainage and unit operation, it is important that the
installation be level. Shim as required to level.
ROOF CURB
Curb Cap Details for Factory-Supplied Roof Curbs
Curb Cap Dimensions
Unit Size
A
B
C
D
E
Install Ductwork:
Installation of all
ducts should be done
in accordance with
SMACNA and AMCA
guidelines. Duct
adapter provided to
support ducts prior to
setting the unit.
ERCH-HP 20
ERCH-HP 45
ERCH-HP 55
ERCH-HP 90
2.00
2.00
2.00
2.00
2.00
4.25
4.25
4.25
1.00
2.00
2.00
2.00
0.88
1.31
1.31
1.31
0.75
0.50
0.50
0.50
All dimensions are in inches.
Set the Unit: Lift
unit to a point directly
above the curb and
duct openings. Guide
unit while lowering
to align with duct
openings. Roof curbs
fit inside the unit base.
Make sure the unit is
properly seated on the
curb and is level.
Set the Unit
Curb Outside Dimensions and Curb Weights (lbs)
Unit Size
L
W
Weight
310
ERCH-HP 20
ERCH-HP 45
ERCH-HP 55
ERCH-HP 90
104.88
115.75
129.88
148.13
51.00
60.63
71.50
90.75
400
510
720
All dimensions are in inches. Weights are for 12 inch high
curbs. Roof curb details, including duct locations dimensions
are available on the roof curb assembly instructions.
Model ERCH-HP Energy Recovery Unit
10
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Ductwork Connections
Rail Mounting / Layout
Examples of poor and good fan-to-duct connections
are shown below. Airflow out of the fan
should be directed straight or curve
the same direction as the
fan wheel rotates. Poor
duct installation will result
• Rails designed to handle the weight of the unit
should be positioned as shown on the diagram
(rails by others).
• Make sure that rail positioning does not interfere
with the supply air discharge opening or the
exhaust air intake opening on the unit. Avoid area
dimensioned “B” below.
• Rails should run the width of the unit and extend
beyond the unit a minimum of 12 inches on each
side.
in low airflow and other
system effects.
POOR
Length of Straight Duct
• Set unit on rails.
GOOD
Recommended Discharge Duct Size and Length
Supply/Exhaust
Opening
Blower
Size
Straight Duct
Length
Unit Size
Duct Size
B
A
ERCH-HP 20
ERCH-HP 45
ERCH-HP 55
ERCH-HP 90
9
14 x 14
20 x 20
20 x 20
28 x 28
36
36
36
60
Side view of unit on rails
Isometric view of unit
10
12
15
Rail Mounting
Unit Size
A
B
All dimensions shown in inches.
ERCH-HP 20
ERCH-HP 45
ERCH-HP 55
ERCH-HP 90
5.0
7.0
5.5
6.0
41.0
41.9
53.0
59.0
•
Recommended duct sizes are based on velocities across the cfm
range of each model at approximately 800 feet per minute (FPM)
at minimum airflow and up to 1600 fpm at maximum airflow.
Recommended duct sizes are only intended to be a guide and
may not satisfy the requirements of the project. Refer to plans for
appropriate job specific duct size and/or velocity limitations.
Straight duct lengths were calculated based on 100% effective
duct length requirements as prescribed in AMCA Publication 201.
Calculated values have been rounded up to nearest foot.
All dimensions are in inches.
•
Exhaust Weatherhood
The exhaust weatherhood is shipped separately as a kit
with its own instructions.
Model ERCH-HP Energy Recovery Unit
11
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Start-Up Unit
Every installation requires a comprehensive start-up
to ensure proper operation of the unit. As part of that
process, the following checklist must be completed and
information recorded. Starting up the unit in accordance
with this checklist will not only ensure proper operation,
but will also provide valuable information to personnel
performing future maintenance. Should an issue arise
which requires factory assistance, this completed
document will allow unit experts to provide quicker
resolve. Qualified personnel should perform start-up to
ensure safe and proper practices are followed.
DANGER
Electric shock hazard. Can cause injury or death.
Before attempting to perform any service or
maintenance, turn the electrical power to unit to OFF
at disconnect switch(es). Unit may have multiple
power supplies.
CAUTION
Use caution when removing access panels or other
unit components, especially while standing on a
ladder or other potentially unsteady base. Access
panels and unit components can be heavy and
serious injury may occur.
Unit Model No. __________________________________
Unit Serial No. ___________________________________
Heat Pump Model No. ____________________________
Energy Wheel Date Code _________________________
Compressor 1 Model No. _________________________
Compressor 2 Model No. _________________________
Start-Up Date ___________________________________
Start-Up Personnel Name ________________________
Start-Up Company _______________________________
Phone Number___________________________________
CAUTION
Do not operate without the filters and birdscreens
installed. They prevent the entry of foreign objects
such as leaves, birds, etc.
CAUTION
Do not run unit during construction phase. Damage to
internal components may result and void warranty.
WARNING
•
Unit was factory tested. All blowers, fans,
and compressors are set-up to run correctly
when supplied power. If any one fan is running
backwards or the compressor is making loud
noises, immediately turn off the power. Switch two
leads on the incoming power to the disconnect.
This will ensure proper operation of the unit.
Failure to comply may damage the compressors
and void the warranty.
•
Do not jumper any safety devices when operating
the unit. This may damage components within or
cause serious injury or death.
•
•
Do not operate compressor when the outdoor
temperature is below 40ºF.
Do not short-cycle the compressor. Allow
5 minutes between “on” cycles to prevent
compressor damage.
•
•
Prior to starting up the unit, power must be
energized for 24 hours without a call for cooling
to allow the compressor crankcase heaters time
to boil off any liquid refrigerant present in the
compressor.
DX system is charged with refrigerant. Start-up
must be performed by EPA Certified Technician.
Model ERCH-HP Energy Recovery Unit
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Pre-Start-Up Checklist
o Disconnect and lock-out all power switches.
SPECIAL TOOLS REQUIRED
• Voltage Meter (with wire probes)
• Amperage Meter
• Pressure Gauges – (refrigerant)
• Tachometer
• Thermometer
• Incline manometer or equivalent
o Remove any foreign objects that are located in the
energy recovery unit.
o Check all fasteners, set-screws, and locking collars
on the fans, bearings, drives, motor bases and
accessories for tightness.
o Rotate the fan wheels and energy recovery wheels
by hand and ensure no parts are rubbing.
Start-Up Procedure
o Check the fan belt drives for proper alignment and
The unit will be in operational mode during start-up. Use
necessary precautions to avoid injury. All data must be
collected while the unit is running. In order to measure
volts and amps, the control center door must be open,
and the unit energized using a crescent wrench to turn
the disconnect handle.
tension.
o Filters can load up with dirt during building
construction. Replace any dirty pleated filters and
clean the aluminum mesh filters in the intake hood.
o Verify that non-motorized dampers open and close
properly.
o Make sure Pre-Start-Up checklist is complete.
o Check the tightness of all factory wiring
o Jumper R to G, R to Y1, and R to Y2 (if applicable)
connections.
on the control board.
o Verify control wire gauge.
o Turn the disconnect on. After 3 minutes
compressors will come on. Make sure all fans and
compressors are rotating the correct direction.
o Verify diameter seal settings on the energy recovery
wheel.
o Verify proper drain trap installation.
o Allow the unit to run until the refrigerant system
o Check condensing fans for any damage or
misalignment. Spin the blades and make sure they
don’t contact any parts and are free turning without
any resistance.
stabilizes. Approximately 1-2 minutes.
Voltage Imbalance
In a 3-phase system, excessive voltage imbalance
between phases will cause motors to overheat and
eventually fail. Maximum allowable imbalance is 2%.
To determine voltage imbalance, use recorded voltage
measurements in this formula.
o Look over the piping system. Inspect for oil at all
tubing connections. Oil typically highlights a leak in
the system.
o Inspect all coils within the unit. Fins may get
damaged in transit or during construction. Carefully
straighten fins with a fin comb.
Key:
V1, V2, V3 = line voltages as measured
VA (average) = (V1 + V2 + V3) / 3
VD = Line voltage (V1, V2 or V3) that
deviates farthest from average (VA)
o If there is an indirect gas-fired furnace in this unit,
refer to the maual provided with this unit for Pre-
Start-Up information.
Formula:
% Voltage Imbalance = [100 x (VA-VD)] /VA
o This unit contains a crankcase heater for each
compressor which needs power supplied to it
24 hours prior to start-up. If start-up is scheduled in
24 hours, unlock the disconnect power and energize
unit.
Model ERCH-HP Energy Recovery Unit
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Unit Start-Up Checklist
Line Voltage. Check at unit disconnect.
L1-L2
Volts
L2-L3
Volts
L1-L3
Volts
Motor Amp Draw
Supply Motor Amps
Exhaust Motor Amps
L1
L1
Amps
Amps
L2
L2
Amps
Amps
L3
L3
Amps
Amps
Fan RPM
Supply Fan RPM
Exhaust Fan RPM
Correct fan rotation direction?
Supply Fan
Exhaust Fan
Yes / No
Yes / No
Energy Wheel Motor
L1
L1
Amps
L2
Amps
L3
Amps
Compressors
Compressor 1
Amps
Amps
L2
L2
Amps
Amps
L3
L3
Amps
Amps
Crankcase Heater
Compressor 2
L1
Crankcase Heater
Amps
Amps
Condensing Fans
Condensing Fan 1
Condensing Fan 2
Condensing Fan 3
L1
L1
L1
Amps
Amps
Amps
L2
L2
L2
Amps
Amps
Amps
L3
L3
L3
Amps
Amps
Amps
Outdoor Air Temperature
Return Air Temperature
Outdoor Air Relative Humidity
Return Air Relative Humidity
Superheat
Deg F
Deg F
% RH
% RH
Deg F Should be between 8º and 12ºF
Deg F Should be between 12º and 17ºF
Subcooling
Discharge Pressure
Suction Line Pressure
Liquid Line Temp
PSIG
PSIG
Deg F
Deg F
Should be between 200 and 280 PSIG for R22 or 300 and 500 PSIG for R410a
Should be between 60 and 80 PSIG for R22 or 100 and 135 PSIG for R410a
Suction Line Temp
Moisture Indicating Sight Glass Liquid Visible? Yes / No
Hot Gas Bypass Operational Yes / No
Color of Center Dot: Green / Yellow
Model ERCH-HP Energy Recovery Unit
14
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Determine the Size of the Main Power
Lines
The unit’s nameplate states the voltage and the unit’s
MCA. The main power lines to the unit should be sized
accordingly. The nameplate is located on the outside of
the unit on the control panel side.
Electrical Information
WARNING
The roof lining contains high voltage wiring. To prevent
electrocution, do not puncture the interior or exterior
panels of the roof.
WARNING
Voltage, Hertz, Phase
To prevent injury or death due to electrocution or
contact with moving parts, lock disconnect switch
open.
VOLTS
HZ
EXH HP
MOP
PH
For units with a gas furnace, if you turn off the power
supply, turn off the gas.
SUP HP
MCA
IMPORTANT
Before connecting power to the unit, read and
understand the following instructions and wiring
diagrams. Complete wiring diagrams are attached on
the inside of the control center door(s).
Electrical Nameplate
Determine the Size of Electric Heater
Wiring
An optional electric heater may require a separate
power supply. The power connection should be made
to the factory-provided electric heater disconnect and
must be compatible with the ratings on the nameplate,
supply power voltage, phase and amperage. Consult
ANSI/NFPA 70 and CSA C22.1 for proper conductor
sizing.
IMPORTANT
All wiring should be done in accordance with the
latest edition of the National Electric Code ANSI/
NFPA 70 and any local codes that may apply. In
Canada, wiring should be done in accordance with
the Canadian Electrical Code.
IMPORTANT
Provide the Opening(s) for the Electrical
Connections
Electrical openings vary by unit size and arrangement
The equipment must be properly grounded. Any
wiring running through the unit in the airstream must
be protected by metal conduit, metal clad cable or
raceways.
and are field-supplied.
Connect the Power Supplies
CAUTION
Connect the main power lines and electric heater power
lines to the disconnect switches or terminal blocks
and main grounding lug(s). Torque field connections to
manufacturer’s recommendations.
If replacement wire is required, it must have a
temperature rating of at least 105ºC, except for an
energy cut-off or sensor lead wire which must be
rated to 150ºC.
Wire the Optional Convenience Outlet
DANGER
The convenience outlet requires a separate 115V power
supply circuit. The circuit must include short circuit
protection which may need to be supplied by others.
High voltage electrical input is needed for this
equipment. This work should be performed by a
qualified electrician.
Connect Field-Wired Low Voltage
Components
Reference the Ladder Diagram on the inside of the
control center door for correct wiring of the following
accessories:
CAUTION
Any wiring deviations may result in personal injury or
property damage. Manufacturer is not responsible
for any damage to or failure of the unit caused by
incorrect final wiring.
• Remote Panel
• Room Temperature Sensor
• Room Dehumidistat
• Discharge Temperature Sensor
Model ERCH-HP Energy Recovery Unit
15
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Most factory-supplied electrical components are
prewired. To determine what electrical accessories
require additional field-wiring, refer to the unit-specific
wiring diagram located on the inside of the control
center access door.
Plumbing / Piping Overview
Condensate Drain Trap
This unit is equipped with a stainless steel condensate
pan with a stainless steel connection. It is important
that the drain connection be fitted with a P trap to
ensure proper drainage of condensate while maintaining
internal static pressures.
The low voltage control circuit is 24 VAC and control
wiring should not exceed 0.75 ohms.
Control wires should not be run inside the same conduit
as that carrying the supply power. Make sure that
field-supplied conduit does not interfere with access
panel operation. All low voltage wiring should be run in
conduit wherever it may be exposed to the weather.
A P trap assembly (kit) is supplied with each unit and
is to be assembled and installed as local conditions
require and according to the assembly instructions
provided with the P trap. If local
and area codes permit, the
condensate may be drained
back onto the roof, but a
drip pad should be provided
beneath the outlet. If local
and area codes require a
If wire resistance exceeds 0.75 ohms, an insulator relay
should be added to the unit control center and wired in
place of the remote switch (typically between terminal
blocks R and G on the terminal strip. The relay must be
rated for at least 5 amps and have a 24 VAC coil. Failure
to comply with these guidelines may cause motor
starters to “chatter” or not pull in which can cause
contactor failures and/or motor failures.
permanent drain line, it should
be fabricated and installed in
accordance with Best Practices
and all codes. In some climates, it will be necessary to
provide freeze protection for the P trap and drain line.
The P trap should be kept filled with water or glycol
solution at all times and it should be protected from
freezing to protect the P trap from damage. If severe
weather conditions occur, it may be necessary to
fabricate a P trap and drain line of metal and install a
heat tape to prevent freezing.
Discharge Air Temperature Sensor
WARNING
Discharge air temperature sensor is to be field-
installed prior to unit start-up.
The sensor is to be installed at least three duct
diameters downstream of the heat
exchangers or where good mixed
average temperature occurs. All
other sensor and low voltage
devices are connected to the low
voltage terminal strip in the control
center. This discharge air sensor is
shipped loose and can be found in
the unit’s control center. See the unit-
specific wiring diagram for connection
locations.
Model ERCH-HP Energy Recovery Unit
16
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Indicator Lights powered by the ER Unit
Optional Remote Control Panel
and Wiring Schematics
R
C
The remote panel is a series of junction boxes ganged
together and includes a stainless steel faceplate. The
remote panel is available with a number of different
alarm lights and switches to control the unit. The remote
panel ships loose and requires mounting and wiring in
the field
Unit On/Off
G
Y1
Y2
W1
Frost Control
Economizer
Rotation Sensor
6
7
12
The remote panel is available with the following options:
•Unit on/off switch
PS2
•Unit on/off light
NC
NC
C
NO
NO
Dirty Filter
•7-day time clock
•Hand/off/auto switch
•Dirty filter light
PS3
C
•Economizer light
•Frost control light
•Wheel rotation sensor light
Dirty Filter Indicator (power by others)
7-Day Timer or On/Off Switch
NC
C
NO
Dirty Filter
7-Day Timer
R
Terminal Block
C
G
in Unit
Control Center
S1 - Unit On/Off
NC
C
NO
Hot
L1
For 7-Day Timer, use blue and black wires.
Red wires should be capped off.
Heating/Cooling Switches and Night Setback
Switch/Timer
Hand/Off/Auto Switch
R
C
Unit On/Off
G
Y1
Y2
W1
6
S1
S6
S7
S4
R
C
Econ/First Stage Cooling
Second Stage Cooling
Terminal Block
in unit
Control Center
Terminal Block
in unit
Control Center
On
G
Off
BMS
Auto
7
12
Hand/Off/Auto Switch allows the unit to
“Off” - off
“On” - Manual Operation
Night Setback Timer
Night Setback Switch
S5
“Auto” - Unit is controlled by BMS, RTU, etc.
NOTE: RTU controllers are by others.
Model ERCH-HP Energy Recovery Unit
17
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Typical Control Center Components - individual components and locations will vary
1. Main disconnect (non-fusible, lockable)
2. Motor starter - exhaust air fan
3. Motor starter - outdoor air fan
4. Motor contactor - energy wheel
5. 24 VAC control transformer
6. 24 VAC terminal strip
Optional Control Center Components
12. DDC controller
13. Dirty filter pressure switches
14. Economizer module
15. Thermostats for:
- Economizer module
7. Fuses for blower motors
8. Grounding lug
- Energy recovery wheel frost control
16. Terminal block
9. Distributor block
10. Compressor fuse blocks
11. Terminal block
17. Frost control pressure switch
18. Energy recovery wheel VFD
17
16
8
6
7
5
1
9
15
4
Component #6
14
Detail of Terminal Strip
3
2
Refer to “Heat Pump System”
section for components in
compressor compartment
13
18
12
10
11
Model ERCH-HP Energy Recovery Unit
18
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Electrical Controls
• Turn the temperature sensor up as high as
possible. The supply blower should cycle on for
one minute, then turn off for one minute.
Optional Frost Control
Extremely cold outdoor air temperatures can cause
moisture condensation and frosting on the enthalpy
wheel. Frost control is an optional feature that will
prevent/control wheel frosting. Three options are
available:
• After testing, set the Timer Scale as follows:
T1 = 10 minutes, T2 = 1 hour
• Set the Timer Settings as follows:
T1 = 0.5, T2 = 0.5. The timer is now set for 5
minutes off and 30 minutes on. Remember to
remove the jumper.
1. Timed Exhaust frost control
2. Electric preheat frost control
3. Modulating wheel frost control
Electric preheat frost control includes an electric
heater (at outdoor air intake) and an airflow pressure
switch (located at the preheater) in addition to the
thermostat and pressure sensor on wheel. When electric
preheat frost control is initiated, the electric preheater
will turn on and warm the air entering the energy wheel
to avoid frosting. Use the following test procedure for
troubleshooting.
All of these options are provided with a thermostat (with
probe) mounted in the outdoor air intake compartment
and a pressure sensor to monitor pressure drop across
the enthalpy wheel. The typical temperature setting
corresponds to the indoor air relative humidity as
shown in the
Frost Threshold Temperatures
Frost Threshold
Indoor RH
at 70°F
Frost Threshold
Temperature
Temperatures
table and
Testing
represents when
frost can occur.
An increase in
pressure drop
would indicate that frost is occurring. Both the pressure
sensor and the outdoor air temperature sensor must
trigger in order to initiate frost control. The two sensors
together ensure that frost control is only initiated
during a real frost condition. Field wiring of a light (or
other alarm) between 6 and C in the control center will
notify personnel when unit is in frost control mode.The
following explains the three options in more detail.
20%
30%
40%
-10º F
-5º F
0º F
• If no DDC controller is present, jumper thermodisc
and jumper the wheel pressure sensor. The heater
should turn on.
• If it doesn’t, either put the outdoor airside doors on
or temporarily jumper the airflow pressure switch
in the preheater control center to avoid nuisance
tripping of the pressure switch. Also check the
airflow switch pressure tap located at the supply
discharge blower to ensure the tubing is connected
and the tap is not blocked. Remember to remove
the jumpers.
Modulating wheel frost control includes a variable
frequency drive in addition to the thermostat and
pressure sensor. When modulating wheel frost control
is initiated, the variable frequency drive will reduce the
speed of the wheel. Reducing the speed of the energy
wheel reduces its effectiveness, which keeps the
exhaust air condition from reaching saturation, thus,
eliminating condensation and frosting. If the outdoor
air temperature is greater than the frost threshold
temperature OR the pressure differential is less than
the set point, the wheel will run at full speed. If the
outdoor air temperature is less than the frost threshold
temperature AND the pressure differential is greater
than the set point, the wheel will run at reduced speed
until the pressure differential falls below the set point.
The temperature and pressure differential set points are
set at the factory, but are field-adjustable. The variable
frequency drive will be fully programmed at the factory.
Timed exhaust frost control includes a timer in
addition to the thermostat and wheel pressure sensor.
When timed exhaust frost control is initiated, the timer
will turn the supply blower on and off to allow the warm
exhaust air to defrost the enthalpy wheel. Default factory
settings are 5 minutes off and 30 minutes on. Use the
following test procedure for troubleshooting.
Testing (refer to Timer diagram)
• Jumper the wheel
pressure switch
A1
B1
15
in the unit control
center. Set the Timer
Scale for T1 and T2
to 1 minute. Set the
Timer Settings for
T1 and T2 to 1.0.
Set the dip switch to
the down position.
(normal position)
0.8 0.6
1.0 0.4
0.2
Dip
Switch
0
T2
1 MIN T2
Timer
Scale
1 MIN T1
0.8 0.6
1.0 0.4
0.2
0
T1
16
18
A2
Timer
Model ERCH-HP Energy Recovery Unit
19
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Optional Economizer
The energy wheel operation can be altered to take
advantage of economizer operation (free cooling). Two
modes are available:
Modulating the wheel: In applications in which an
internal heat gain is present in the space, the rotational
speed of the energy wheel may be modulated (via
variable frequency drive) to avoid overheating the space
during the winter. The speed of the energy wheel will be
controlled in response to the discharge temperature set
point.
1. De-energizing the wheel.
2. Modulating the wheel.
A field-supplied call for cool (Y1) is required. De-
energizing the wheel is accomplished with a signal
from a temperature or enthalpy sensor mounted in
the air intake compartment. This primary sensor will
de-energize the energy wheel when the outdoor air
temperature (factory default is 65ºF) or enthalpy (factory
default is the ‘D’ setting) is below the field adjustable set
point. An override temperature sensor is also furnished
in the outdoor air intake compartment to deactivate
economizer mode. The override (with field adjustable set
point) is set at some temperature lower than the primary
sensor (factory default is 50ºF). Effectively, the two
sensors create a deadband where the energy recovery
wheel will not operate and free cooling from outside can
be brought into the building unconditioned.
Sequence of operation: The variable frequency drive
is fully programmed at the factory. A “call for cool” must
be field wired to the unit (terminals provided in unit -
refer to wiring diagram in unit control center) to allow for
initiation of economizer mode. When the space calls for
cooling, factory supplied controls will drive the following
wheel operations:
Where (TOA) is the outdoor air temperature set point,
(TRA) is the return air temperature set point, and (TSA) is
the supply air discharge thermostat set point.
Wheel runs at full speed.
TAO > TRA
(maximum energy recovery)
Testing
T
AO < TRA
and
AO > TSA
Wheel is stopped.
Temperature Sensor with Override
(no energy recovery)
T
• Turn both temperature and override thermostats
down as low as they go. The wheel should be
rotating.
TAO < TRA
and
T
Wheel will modulate to maintain
discharge temperature.
AO < TSA
• Turn the temperature sensor up as high as it goes,
and keep the override sensor as low as it will go.
The wheel should stop rotating.
Phase Monitor
The unit control circuitry includes a phase monitor that
constantly checks for phase
reversal, loss of phase or a
power brownout. It requires
24 VAC to operate and when
it detects a fault, it cuts off the
24 VAC that goes to the low
• Turn both sensors as high as they will go. The
wheel should start rotating.
• Set the temperature sensor at desired point for
economizer operation to begin. Set the override
sensor at desired point for economizer operation to
end (factory default is 65ºF and 50ºF, respectively).
Enthalpy Sensor with Override
voltage terminal strip, thereby
shutting off all motors.
Typical Phase Monitor
• Turn unit power off. Disconnect C7400 solid state
enthalpy sensor from terminal So on the enthalpy
controller. Also, disconnect the 620 ohm resistor
from terminal Sr on the enthalpy
Variable Frequency Drive (VFD)
If a VFD was provided and installed at the factory, it has
been preset to control the speed of the blower motor for
optimum performance. The motor speed needs to be
verified during test and balance of the unit.
controller. Turn unit power on. The
LED on the enthalpy controller
should light and the energy recovery
wheel should not rotate.
• Turn unit power off. Reconnect
620 ohm resistor to terminal Sr on
the enthalpy controller. Turn unit
power on. The LED on the enthalpy
controller should not light and
Enthalpy
the energy recovery wheel should
Controller
energize and rotate.
If the steps above provide the results described, the
enthalpy economizer is working properly.
Typical Variable Frequency Drive (VFD)
Refer to unit-specific documentation.
• Turn unit power off. Reconnect C7400 solid state
enthalpy sensor to terminal So.
Model ERCH-HP Energy Recovery Unit
20
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Optional Rotation Sensor
The rotation sensor monitors energy wheel rotation. If
the wheel should stop rotating, the sensor will close a
set of contacts in the unit control center. Field-wiring of
a light (or other alarm) between terminals R and 12 in
the unit control center will notify maintenance personnel
when a failure has occurred.
Dirty Filter Sensor
Dirty filter sensors monitor pressure drop across the
outdoor air filters, exhaust air filters, or both. If the
pressure drop across the filters exceeds the set point,
the sensor will close a set of contacts in the unit control
center. Field-wiring of a light (or other alarm) to these
contacts will notify maintenance personnel when
filters need to be replaced. The switch has not been
set at the factory due to external system losses that
will affect the switch. This switch will need minor field
adjustments after the unit has been installed with all
ductwork complete. The dirty filter switch is mounted in
the exhaust inlet compartment next to the unit control
center or in unit control center.
Setscrew (on front of switch) must
be manually adjusted after the
system is in operation.
Negative pressure connection
is toward the ‘front or top’ of
the switch. (senses pressure on
the blower side of filters)
Positive pressure connection is toward the ‘back or bottom’
of the switch. (senses pressure at air inlet side of filters)
To adjust the switch, the unit must be running with
all of the access doors in place, except for the
compartment where the switch is located (exhaust
intake compartment). The adjusting screw is located on
the top of the switch. Open the filter compartment and
place a sheet of plastic or cardboard over 50% of the
filter media. Replace the filter compartment door. Check
to see if there is power at the alert signal leads. Whether
there is power or not, turn the adjustment screw on the
dirty filter gauge (clockwise if you did not have power,
counterclockwise if you did have power) until the power
comes on or just before the power goes off. Open the
filter compartment and remove the obstructing material.
Replace the door and check to make sure that you do
not have power at the alert signal leads. The unit is now
ready for operation.
Model ERCH-HP Energy Recovery Unit
21
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Energy Wheel
Start-Up
If selected, the energy wheel is installed in the unit’s
airstream with one half of the wheel in the intake
airstream and one half in the exhaust airstream. Air
leakage between the two airstreams has to be kept to
a minimum and the wheel has air seals that must be
adjusted for that purpose. The seals must be adjusted
at time of start-up. The wheel can be accessed through
the door labeled Energy Wheel Access.
should be a slight tug on the paper. Tighten the screws,
repeat the steps on the other set of seals.
Push the wheel cassette back into the unit and plug
in the power connector. Turn the main power supply
back on and then observe the operation of the wheel by
opening the wheel access door slightly. Remove filters if
necessary to observe the wheel.
Bearing Support
Sequence of Operation
Optional Economizer - The economizer will be locked
out when: the outside air is <40°F (- 2°F hysteresis,
adjustable); the unit is operating in dehumidification
mode; or there is a call for heating.
Adjustable
Air Seals
• Stop Wheel: When economizer mode is enabled
and there is a signal for cooling, the wheel will stop
rotating to allow free cooling.
Label showing
cassette serial number
and date code
• Modulate Wheel: When economizer mode is
enabled and there is a signal for cooling, the
wheel VFD modulates wheel speed to maintain the
discharge temperature set point.
Drive Belt
Drive Pulley
Drive Belt
Optional Frost Control - The DDC controller will
output a signal when wheel frosting is occurring which
is determined by a temperature set point (OA <5°F –
2°F hysterisis, adjustable) and wheel pressure drop
increase.
Inspect the drive belt. Make
sure the belt rides smoothly
in the pulley and around the
outside of the wheel. Note
the directional arrow and
data information shown in the
• Preheat: When frosting is occurring, the preheater
is energized to defrost the wheel. Once the
pressure drop decreases below the set point, the
preheater is de-energized.
image.
Motor Pulley and Belt
Adjust the Air Seals
• Timed Exhaust: When frosting is occurring, the
supply blower is cycled off. The exhaust blower
shall continue to run, allowing the warm exhaust
air to defrost the wheel. After the 10 minute cycle,
the supply fan are re-energized to continue normal
operation.
The first step in wheel seal adjustment is to make sure
the unit power supply is locked out. Disconnect the
wiring to the wheel module and pull the wheel cassette
out of the cabinet on its tracks. Large cassettes are not
removable. Then slowly rotate the wheel by hand to
make sure there is no binding or
misalignment. The wheel should
Alarms Indication - DDC shall have one digital output
rotate smoothly and should not
for remote indication of an alarm condition.
bind.
• Wheel Rotation Alarm: Monitors wheel rotation,
and sends a signal to controller (after a 15 second
time delay with no rotation) that signals the DDC to
activate an alarm.
There is a perimeter seal located
around the outside of the wheel
and a diameter seal across the
face of the wheel on both sides.
Check to make sure that all air
Retaining
seals are secure and in good
Screws
condition.
Adjust the air seals by loosening
all the air seal retaining screws
on the bearing support (see
image for reference). Using a
piece of paper as a feeler gauge,
adjust the seals so they almost
touch the face of the wheel while
tugging slightly on the paper.
When the wheel is rotated, there
Bearing Support Bar
showing air seal assembly
Model ERCH-HP Energy Recovery Unit
22
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Energy Wheel Maintenance
WARNING
Cleaning
Maintenance or cleaning of the wheel segments
should be done with the segments removed from
the wheel cassette to avoid splashing liquids or
cleaning agents inside the cabinet. If the energy wheel
appears excessively dirty, it should be cleaned to
ensure maximum operating efficiency. Only excessive
buildup of foreign materials needs to be removed.
DISCOLORATION AND STAINING OF ENERGY
RECOVERY WHEEL DOES NOT AFFECT ITS
PERFORMANCE.
Whenever performing maintenance or inspections,
always disconnect the power source.
Inspection
The wheel should be inspected semiannually
in accordance with the maintenance schedule.
Maintenance of the wheel consists
mainly of inspecting the wheel
for cleanliness and then checking
the drive motor, belt, and pulley
for wear. If the wheel layers
Thoroughly spray the wheel matrix with a household
cleaner such as Fantastik™ or the equivalent. Gently
rinse with warm water and use a soft brush to remove
any heavy accumulations. A detergent/water solution
can also be used. Avoid aggressive organic solvents,
such as acetone. Wheel segments can be soaked in the
above solution overnight for removal of stubborn dirt or
accumulations.
appear dirty, the wheel should be
disassembled and cleaned.
The wheel rotates through the two
airstreams which are moving in
opposite directions, the wheel is
self-cleaning, up to a point. If the
wheel media becomes blocked by
dirt or dust, or if the media collects a layer of smoke
residue or an oily film, the energy transfer efficiency
drops.
Energy Wheel
Cassette
After cleaning is complete, shake excess water from the
wheel or segments. Dry the wheel or segments before
putting them back into the cassette.
Reassembly
The main factor in the frequency of cleaning is the
cleanliness of the air. If air filters are not changed
frequently, the wheel will collect contaminants and will
then have to be cleaned.
When reinstalling the segments, be sure to install them
with the correct face toward the motor side of the
cassette. Note that one face of each segment is smooth
and the other face has a reinforcing channel or support
cut into the surface.
Wheel Disassembly
Wheels are part of a cassette that may be pulled from
the unit for easy access. There may be a small damper
assembly or other component that blocks removal of
the cassette. Before sliding out the cassette or any other
component, disconnect any power supply cord and
secure it so it cannot jam or otherwise get damaged.
Wheel Segment
(Pulley Side)
Wheel Segment
(Motor Side)
Each wheel has removable segments that hold the
coated layers of media and each segment is held in
place with two retaining
Energy Recovery Wheel Belt
clips located on the outer
Inspect belts each time filters are replaced. Belts that
look chewed up or are leaving belt dust near the motor
pulley may indicate a problem with the wheel. Be sure to
inspect wheel for smooth and unrestricted rotation. If a
belt requires replacement, contact the local Greenheck
representative. Instructions for replacement will ship
with the new belt.
rim of the wheel. When
removing more than one
segment, remove them in
sequence from opposite
Segment Retaining Clip
sides of the wheel (180 degrees apart) to reduce the
imbalance. Secure the wheel against rotation. Carefully
release the two retaining clips and swing them fully
open. The segment can now be removed by pushing the
face of the segment close to the outer rim of the wheel.
Wheel segments are built to close tolerances and the
segment may have to be jiggled to remove it. Do not
use a hammer or otherwise force the segment because
these are high value items and are not built to withstand
abuse.
Energy Recovery Wheel Bearing
In the unlikely event that a wheel bearing fails, the
bearing is behind a removable plate on the wheel
support beam (slide cassette halfway out of cabinet to
access). Contact the local Greenheck representative for
detailed instructions on how to replace the bearing.
Whenever retaining clips are opened, they should be
closed as soon as possible. If the wheel should rotate
when a clip is open, the clip will jam against the bearing
support bar and could cause damage.
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Energy Wheel Troubleshooting
Symptom
Possible Cause
Corrective Action
See air seals under Start-Up, Energy Wheel
section.
Air seals are too tight.
Broken belt.
Energy wheel
does NOT turn
Replace.
Make sure wheel drive is plugged in. Verify
power is available.
No power to wheel motor.
Recheck air seals, make sure they are not too
tight. See Adjust the Air Seals under Start-Up,
Energy Wheel section.
Energy wheel
runs intermittently
Wheel motor overloads are tripping due to
rubbing between wheel and air seals.
Heat Pump Overview
Every unit has a complete, sealed refrigeration system
that is ready for connection to a water source.
Liquid Line Filter Drier
The liquid line filter drier prevents moisture and foreign
matter from entering the thermal expansion valve. It is
located in the compressor compartment.
The heat pump has all the typical DX components and
also has refrigerant reversing valve(s) to enable the
system to work in both heating and cooling modes.
Hot Gas Bypass Valve
On units equipped with hot bypass, hot gas from the
compressor is injected into the liquid line of the airside
coil after the TXV. This process starts when suction gas
temperatures drop below 28ºF, which is 32º–34ºF coil
surface temperature. Hot gas helps the airside coil from
freezing up and the compressor from cycling. The valve
is factory set, but should be field adjusted to maintain a
suction pressure of 90 psi.
Factory-Installed Heat Pump System
Components:
Thermostatic Expansion Valve (TXV)
Each compressor is equipped with a thermal expansion
valve. The valve controls the flow of liquid refrigerant
entering the evaporator coil by maintaining a constant,
factory set superheat of 10ºF.
Refrigerant Distributor
Valve Adjustment: To adjust the valve, connect
a pressure gauge to the suction line and block the
entering air to the coil. The valve should begin to open
when the suction pressure drops to approximately
58 PSIG (the valve will feel warm to the touch).
Adjustments are made by first removing the cap
on the valve and then turning the adjusting stem
counterclockwise to decrease the pressure. Allow
several minutes between adjustments for system to
stabilize. When adjustment is complete, replace the
cap on the valve.
Attached to the TXV is a refrigerant distributor. The
refrigerant distributor evenly distributes the refrigerant
to each circuit of the airside coil to provide optimum
performance.
Airside Coil
Each unit uses a single refrigerant coil known as an
airside coil. If two compressors are used in the unit,
then the airside coil will be a split configuration so that
each compressor has a dedicated portion of the airside
coil. Depending on whether the unit is in cooling or
heating mode, the airside coil will function as either
a condensing coil or an evaporator coil. See also
Subassemblies/Coils.
Reversing Valve
Each compressor is equipped with a reversing valve
to reverse the direction of refrigerant flow. The valve is
electrically actuated.
Coaxial Refrigerant-to-Water Heat Exchanger
The unit uses one coaxial heat exchanger per
compressor, essentially a tube inside a tube. Water
flows through the inner copper tube and compressed
refrigerant is forced through the spaces between the
inner and outer tubes. Depending on whether the unit
is functioning in a cooling or a heating capacity, heat is
rejected from one tube to the other.
Access Ports
For easy measurement and charging access, several
ports are provided throughout the system. These can be
used to measure system pressures and also charge or
evacuate the system.
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Heat Pump Controls
Freeze Sensor
Each unit is factory provided with a Unit Protection
Module (UPM) that controls compressor operation and
monitors the safety controls that protect the unit. The
UPM is a printed circuit board and is found in the heat
pump module.
This is optional and can be set to ignore or monitor a
freeze sensor. There are two configurable freeze points,
35°F and 15°F. The unit will enter a soft lockout until the
temperature climbs above the set point and the anti-
short cycle time delay has expired.
Safety controls include the following:
• High pressure switch located in the refrigerant
discharge line and wired across the HPC terminals
on the UPM.
• Low pressure switch located in the unit refrigerant
suction line and wired across terminals LPC1 and
LPC2 on the UPM.
NOTE
If unit is employing a fresh water system (no anti-
freeze protection), it is extremely important to have
the “Freeze” switch set to 35°F in order to shutdown
the unit at the appropriate leaving water temperature
and protect your heat pump from freezing if a freeze
sensor is included.
The UPM includes the following features:
Anti-Short Cycle Timer
Crankcase Heater
Five minute delay on break timer to prevent compressor
A crankcase heater is installed around the base of each
compressor in the unit to boil-off any liquid refrigerant
that may be absorbed into the oil during idle periods. It
is recommended the heater operate 24 hours prior to
the compressors being started.
short cycling.
Random Start
Each controller has a unique random start delay ranging
from 270 to 300 seconds to reduce the chances
of multiple units simultaneously starting after initial
power up or after a power interruption, creating a large
electrical spike.
Low Pressure Bypass Timer
The low pressure switch is bypassed for 120 seconds
after compressor start-up to prevent nuisance low
pressure lockouts during cold start-up in the heating
mode. If the low pressure switch remains opened after
120 seconds, the unit enters a soft lock.
Brownout/Surge/Power Interruption Protection
The brownout protection in the UPM board will shut
down the unit if the incoming power falls below 18 VAC.
The unit will remain off until a minimal incoming power
of 18 VAC is detected. Once proper power is restored,
the unit will start-up within the random start time period.
Malfunction Output
The controller has a set of wet contacts for remote fault
indication or dry contacts for communication with a
DDC controller or BMS. The fault output will depend on
the dip switch setting for “ALARM”. If set to “CONST”, a
constant signal will be produced to indicate a fault has
occurred and the unit requires inspection to determine
the type of fault. If it is set to “PULSE”, a pulse signal
is produced and a fault code is detected by a remote
device indicating the fault. The remote device must have
a malfunction detection capability when the UPM board
is set to “PULSE”.
Test Dip Switch
A test dip switch is provided to reduce all time delay
settings to five seconds during troubleshooting or
verification of unit operation. Note that operation of the
unit while in test mode can lead to accelerated wear and
premature failure of the unit. The “TEST” switch must be
set back to “NO” for normal operation.
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Refrigeration System Schematic
Typical Operating Conditions
Location
Refrigerant State Temperature Pressure Superheat/Subcool
Before water-to-refrigerant
heat exchanger
Hot Vapor
150°F
85°F
330 PSIG 50°F Superheat
330 PSIG 15°F Subcool
Cooling
Mode /
After water-to-refrigerant
heat exchanger
Warm Liquid
Refrigerant
Properties
After Thermostatic
Expansion Valve
Saturated Liquid-
Vapor mix
-45°F
55°F
144 PSIG
After Airside Coil
Cold Vapor
145 PSIG 10°F Superheat
Water entering the coaxial heat exchanger is warmed by the heat it absorbs from the refrigerant and leaves about
10°F warmer.
Location
Before Airside Coil
After Airside Coil
Refrigerant State Temperature Pressure Superheat/Subcool
Hot Vapor
130°F
65°F
250 PSIG 50°F Superheat
250 PSIG 15°F Subcool
Warm Liquid
Heating
Mode /
After Thermostatic
Expansion Valve
Saturated Liquid-
Vapor mix
-35°F
45°F
120 PSIG
Refrigerant
Properties
After water-to-refrigerant
heat exchanger
Cold Vapor
120 PSIG 10°F Superheat
Water entering the coaxial heat exchanger is cooled because of the heat being absorbed by the refrigerant and
leaves about 6°F warmer.
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Unit Protection Module (UPM)
Fault Indications
Each unit includes one Unit Protection Module (UPM)
printed circuit board and each UPM has two LED
indictor lights.
Lockout Reset
A hard lockout can be reset by turning the unit
thermostat off and then back on when the “RESET” dip
switch is set to “Y” or by shutting off unit power at the
circuit breaker when the “RESET” dip switch is set to
“R”.
LED
LED Fault Indication
Color
Your UPM board will come
Default Settings
Power LED indicates 18-30 VAC present at
Green
from the factory with the
the board
Freeze
Temp
NO
35°
2
following default settings:
Dual or
# of
blinks
Single
Status
Compressor
Lockout
Reset
High pressure lockout
Compressor 1
T
1
2
3
4
5
Alarm
CONT
NO
HOT
Low pressure lockout
Compressor 1
Test
Hot/Dry Alarm
High pressure lockout
Compressor 2
Low pressure lockout
Compressor 2
Dual
Compressor
Freeze sensor lockout
(optional item)
Condensate overflow
in coil drain pan
(optional item)
Red
6
7
Brownout AC voltage
to R and C terminal
below 18 VAC
1
2
High pressure lockout
Low pressure lockout
Freeze sensor lockout
(optional item)
3
Single
Compressor
Condensate overflow
in coil drain pan
(optional item)
4
Brownout AC voltage
to R and C terminals
below 18 VAC
5
Intelligent Reset
If a fault condition is initiated, the five minute delay
on break time period and the random start timer is
initiated and the unit will restart after these delays
expire. During this period the fault LED will indicate
the cause of the fault. If the fault condition occurs 2 or
4 times (depending on 2 or 4 setting for Lockout dip
switch) before 60 minutes, the unit will go into a hard
lockout and requires a manual lockout reset. A single
condensate overflow fault will cause the unit to go into
a hard lockout immediately, and will require a manual
lockout reset.
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Troubleshooting - Controller Alarms
The first step in troubleshooting the unit is to check
the on-board alarm indicators. Several of the electronic
controls in the unit monitor the system for faults and will
go into alarm, shutting down the unit or a single function
within the unit.
DDC Controller
Check the screen on the DDC for an alarm condition. If
the DDC is
in an alarm
condition, a
message will
show on the
DDC screen.
The DDC is located in the main control center. If the
DDC is in alarm condition, the alarm button will blink
red. Press the alarm button to see the specific condition
or to reset the DDC. Refer to the DDC Installation
Operations and Maintenance manual for detailed
information on fault codes and see the unit-specific
wiring diagram.
Phase Monitor
The phase monitor has two
LED indicator lights, one
red and one green. Green
indicates proper operational
status, red indicates the unit
has detected a fault and is in
alarm condition.
Variable Frequency Drive (VFD)
Variable frequency drives have a
display screen that will show an
alarm condition. If a fault such
as a voltage spike occurs, the
VFD will go into alarm and will
not reset until a hard restart is
performed. See the unit-specific
manufacturer’s manual supplied
with the unit. VFDs are located in
the main control center.
FX05 Furnace Controller
Present only if an indirect gas-fired furnace option is
present.
The FX05 furnace controller will display an alarm
condition if present. The controller will be found in the
furnace control cneter. See the
furnace installation, operation
and maintenance manual and
the controller manufacturer’s
unit-specific manul for further
information.
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Troubleshooting – Airflow
The Test and Balance Report (TAB) is utilized to determine whether the appropriate amount of outdoor air
and exhaust air is being supplied and removed from a building, respectively. There are no set rules on what
information must be included in a TAB report. As such, if a TAB report indicates that the airflow on a unit is low,
prior to contacting the factory, please determine the following information:
Unit #1
Unit #2
Unit #3
Unit #4
Model Number
Serial Number
Nameplate Information
Voltage
Hertz
Phase
Outdoor Air Fan Amps
Outdoor Air Fan Horsepower
Design Airflow
Outdoor Air
Measured Airflow
Outdoor Air
Measured Data
Blower Rotation
Outdoor Air Fan RPM
Outdoor Air Fan Amp Draw
Airflow problems can often be tied back to improper ductwork installation. Be sure to install ductwork in accordance
with SMACNA and AMCA guidelines.
Troubleshooting – Unit
Symptom
Possible Cause
Corrective Action
Blown fuse or open circuit breaker.
Defective motor or capacitor.
Motor starter overloaded.
Replace fuse or reset circuit breaker and check amps.
Replace.
Reset starter and check amps.
Blower fails to
operate
Check for On/Off switches. Check for correct supply
voltage.
Electrical.
Drive.
Check for broken or loose belts. Tighten loose
pulleys.
Shorten wiring run to mechanical room or install a
relay which will turn unit on/off. Consult Factory for
relay information. Increase wire gauge size so that
resistance is .075 ohms or less.
Control power (24 VAC) wiring run is too long
(resistance should not exceed 0.75 ohms).
Motor starters
“chatter” or
Incoming supply power is less than anticipated.
Voltage supplied to starter coil must be within
+10% / -15% of nominal voltage stated on the
coil.
do not pull in
Need to increase supply power or use a special
control transformer which is sized for the actual
supply power.
Always have a completed Pre Start-Up Checklist and Unit Start-Up Checklist prior to requesting parts or service information.
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Troubleshooting – Unit
Symptom
Possible Cause
Corrective Action
CFM too high.
Check cfm and adjust drives if needed.
If higher, ductwork should be improved.
If lower, fan rpm should be lower.
Static pressures are higher or lower than design.
Blower rotation is incorrect.
Motor voltage incorrect.
Check rotation and reverse if necessary.
Motor over amps
Check motor nameplate versus supplied voltage.
See specifications and catalog for fan curves to
determine if horsepower is sufficient.
Motor horsepower too low.
Shorted windings in motor.
Unit damper not fully open.
Replace motor.
Adjust damper linkage or replace damper motor.
Improve ductwork to eliminate losses using good
duct practices.
System static pressure too high.
Blower speed too low.
Check for correct drives and rpm with catalog data.
For 3-phase, direction can be reversed by
interchanging any two of the three electrical leads.
Fan wheels are operating backwards.
Low airflow (cfm)
Follow cleaning procedures in Routine Maintenance
section.
Dirty filter.
Leaks in ductwork.
Repair.
Elbows or other obstructions may be obstructing
fan outlet.
Correct or improve ductwork.
Adjust belt tension.
Belt slippage.
Check for correct fan rpm. Decrease fan speed if
necessary.
Blower fan speed too high.
Filter(s) not in place.
Install filters.
High airflow (cfm)
Induce Ps into system ductwork. Make sure grilles
and access doors are installed. Decrease fan speed if
necessary.
Insufficient static pressure (Ps) (airflow
resistance).
Adjust wheel and/or inlet cone. Tighten wheel hub or
bearing collars on shaft.
Fan wheel rubbing on inlet.
Bearings.
Replace defective bearing(s). Lubricate bearings.
Tighten collars and fasteners.
Wheel out of balance.
Loose wheel on shaft.
Loose motor or blower sheave.
Belts too loose.
Replace or rebalance.
Tighten wheel setscrew.
Tighten sheave setscrew.
Adjust belt tension after 24 hours of operation.
Excessive noise
or vibration
Loosen to maintain a 3/8 inch deflection per foot of
span between sheaves.
Belts too tight.
Worn belt.
Replace.
Motor base or blower loose.
Buildup of material on wheel.
Bearing and drive misaligned.
Tighten mounting bolts.
Clean wheel and housing.
Realign.
Make sure ductwork is supported properly. Make
sure ductwork metal thickness is sized for proper
stiffness. Check duct size at discharge to ensure that
air velocities are not too high.
Noise being transmitted by duct.
Always have a completed Pre Start-Up Checklist and Unit Start-Up Checklist prior to requesting parts or service information.
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Troubleshooting – Refrigeration Circuit
TROUBLESHOOTING NOTE
IMPORTANT
Do not release refrigerant to the atmosphere! If
required service procedures include the adding or
removing of refrigerant, the service technician must
comply with all federal, state and local laws. The
procedures discussed in this manual should only be
performed by an EPA Certified Technician.
Before any components are changed on the
refrigeration system, the cause of the failure must be
identified. Further problems will exist unless the true
cause or problem is identified and corrected.
NOTE: Unit is equipped with a phase loss/phase reversal control. If system does not start, check phase of electrical supply.
Symptom
Possible Cause
Corrective Action
Open disconnect switch or circuit breaker.
Close switch and / or breaker.
Check voltage to contactor coil, transformer, slave
relay, system. Replace parts as necessary.
Compressor contactor not closing.
Blown fuse or tripped breaker.
Low line voltage.
Check for reason and repair. Replace fuse after
correcting problem.
Check line voltage. If more than 10% from
compressor marking, correcting is necessary.
Motor thermal protector automatically resets.
Allow time (2 hrs.) for compressor to cool down so
protector will reset. Restart and check for reason
overheat occurred.
Compressor motor protector open.
Compressor defective.
Compressor
will not run
or
does not
try to start
Check motor for open circuit, short circuit,
grounded windings or burn out.
Compressor may be seized; check refrigerant.
If necessary, replace compressor.
If manual reset (high pressure), reset switch.
(Switch opens at 600 psi and will not reset above
420 psi for R-410A.
High or low pressure switch open or defective.
If auto reset (low pressure) does not reset and
everything else is OK, replace switch.
Open room thermostat or control
(no cooling required).
Check room temperature. If temperature is proper,
wait for thermostat to close.
Loose wiring.
Check all wire terminals and tighten as necessary.
Check refrigerant pressures.
Low refrigerant charge.
Compressor starts
but cuts out on low
pressure
Check for dirty evaporator coil, dirty filters,
dampers closed, iced evaporator coil, improper
belt, check motor amps, check duct design.
Airflow restricted.
Check refrigerant pressure, check and adjust
thermal expansion valve. If not functioning properly,
check for pressure drop across the filter drier.
Low pressure
switch activates
at 50 PSIG for R-410A
Restriction in refrigerant line.
Defective low pressure switch.
Replace.
Always have a completed Pre Start-Up Checklist and Unit Start-Up Checklist prior to requesting parts or service information.
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Troubleshooting – Refrigeration Circuit
Symptom
Possible Cause
Corrective Action
Refrigerant overcharge.
Check pressures, charge by subcooling.
Condenser fan motor defective.
Check fan motor.
Compressor starts
but cuts out on high
pressure switch
Condenser coil inlet obstructed or dirty.
Check coil and inlet clearances.
Check high side equalized pressure reading with
equivalent outdoor temperature.
Air or non-condensables in system.
Defective high pressure switch.
Replace.
High pressure
activates at
600 PSIG for
R410A
Check refrigerant line pressures, check thermal
expansion valves.
Restriction in discharge or liquid line.
Condensing fan relay not pulling in.
Reheat valve and bypass valve not opening.
Low voltage.
Replace.
Check valves or valve circuit board.
Check voltage.
Check running amperage and conditions described
under ‘Low suction pressure’ symptoms.
Sustained high discharge pressure.
Check thermal expansion valve setting, check for
air in system.
High suction and discharge pressures.
Defective compressor overload.
If compressor is hot, allow compressor to cool for
two hours. Recheck for open circuit.
Compressor cuts out
on thermal overload
Improper refrigerant charge.
Improperly wired.
Check subcooling.
Review wiring schematics.
Loose wiring.
Check all connections and wires.
Replace relay.
Defective start relay.
Motor windings damaged.
Improperly wired.
Low line voltage.
Loose wiring.
Verify amp draw.
Review wiring schematics.
Check voltage.
Check all connections.
Compressor hums,
but will not start
Defective start or run capacitor.
Check run capacitor for compressor and fan motor.
Defective relay start.
Replace relay.
Motor winding damaged.
Verify amp draws.
Internal compressor mechanical damage.
Replace.
Always have a completed Pre Start-Up Checklist and Unit Start-Up Checklist prior to requesting parts or service information.
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Troubleshooting – Refrigeration Circuit
Symptom
Possible Cause
Corrective Action
Refrigerant overcharge.
Check pressures and subcooling.
Check thermal expansion valve setting. Check for
refrigerant overcharge.
Liquid floodback.
Tubing rattle.
Dampen tubing vibration by taping or clamping.
Carefully bend tubing away from contact where
possible.
Compressor noisy
or vibrating
Scroll compressor rotating in reverse (3 phase).
Worn or damaged compressor.
Rewire for opposite rotation.
Replace the compressor.
Improper mounting on unit base.
Check that compressor is properly isolated.
Check for high entering wet bulb temperature.
Check for excessive air.
Excessive load on evaporator coil.
Compressor is unloaded.
Check head pressure, check thermal expansion
valve if not functioning properly, check pressure
drop across filter drier.
Check the thermal expansion valve, ensure bulb is
insulated.
Check superheat. If superheat is high, then valve is
out of control and pegged wide open.
• Check bulb for contact.
Expansion valve not secured to suction line.
High suction
pressure
• Adjust valve for superheat.
• Replace valve powerhead or valve.
Thermostatic expansion valve pressure limit
feature incorrect or inoperative. Overfeeding.
Check bulb location and clamping. Adjust
superheat. Replace expansion valve power head.
Room load too large.
Overcharged.
Reduce the load or add more equipment.
Check pressures and subcooling.
Check thermal expansion setting and calibrate
superheat.
Thermal expansion valve setting.
Check for proper clearances and possible air
recirculating.
Air inlet to condenser dirty or obstructed.
Condenser fan motor defective.
Too much refrigerant.
Check condenser fan motor.
Remove excess refrigerant.
Remove non-condensable from system.
Clean condenser coil.
High discharge
pressure
Non-condensable in system.
Dirty condenser coil.
Condenser fan not running or running
backwards.
Check electrical circuit and fuse. Check fan cycling
controls.
Discharge service valve partially closed.
High load conditions.
Open valve.
Add more equipment or reduce load.
Always have a completed Pre Start-Up Checklist and Unit Start-Up Checklist prior to requesting parts or service information.
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Troubleshooting – Refrigeration Circuit
Symptom
Possible Cause
Corrective Action
Refrigerant undercharge.
Check pressures and subcooling.
Interchange any two wires from 3 phase
disconnect.
Blower running backward.
Loose blower, pulley or belts.
Check drive pulley alignment, belt tension.
Low entering air temperature (low load condition). Check entering air wet bulb conditions.
Check system for leaks. Repair leaks and add
Refrigerant leak.
refrigerant.
Low suction
pressure
Check defrost system. Clean the coil.
Evaporator dirty or iced up or airflow restricted.
Check fan operation. Check airflow.
Plugged liquid line filter-drier.
Replace filter-drier.
Improper suction pressure regulator setting.
Check setting and correct as required.
Expansion valve defective, superheat too high, or Adjust valve for proper superheat or replace the
valve too small.
expansion valve if too small or defective.
Moisture in system.
Reclaim refrigerant, check for leaks, recharge.
Check subcooling, check for leak. Repair leak and
add refrigerant.
Insufficient refrigerant charge.
Defective or improperly adjusted expansion
valve.
Check superheating and adjust thermal expansion
valve.
Low discharge
pressure
Low suction pressure.
See “Low suction pressure”.
Check condenser controls and reset to obtain
desired condensing temperature.
Faulty condenser temperature controls.
Thermostat location or malfunction.
Check thermostat, check heat anticipator setting.
Improper refrigerant charge.
Defective high or low pressure control.
Liquid floodback.
Check subcooling, verify superheat.
Check high or low pressure switch.
Possible tight bearings.
Defective expansion valve.
Poor air distribution.
Check thermal expansion valve and superheat.
Check ductwork for recirculating.
See “High discharge pressure”.
See “High suction pressure”.
Compressor
short cycles
High discharge pressure.
Leaking discharge valves in compressor.
Low airflow at evaporator(s).
Check blower operation and airstream restrictions.
Contact factory.
Incorrect unit selection (oversized).
Always have a completed Pre Start-Up Checklist and Unit Start-Up Checklist prior to requesting parts or service information.
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Troubleshooting – Refrigeration Circuit
Symptom
Possible Cause
Corrective Action
Thoroughly defrost evaporator. After defrost,
observe level, add oil. Check for leaks. Check lines
for proper slope and traps.
Low oil level (trapped oil in evaporator or suction
line).
Adjust expansion valve for higher superheat. Check
crankcase heater.
Excessive liquid refrigerant in the crankcase.
Low or no
oil pressure
Worn oil pump.
Replace the oil pump.
Worn compressor bearings.
Replace the compressor.
Loose fitting on oil line or pump housing gasket
leaking.
Check and tighten system. Check bottom plate or
compressor.
Compressor short cycling.
Refrigerant leak.
Check low pressure control setting.
Check system for leaks. Repair leaks and add
refrigerant.
Short cycling.
Check low pressure control settings.
Compressor
loses oil
Check thermal expansion valve setting. Check for
refrigerant overcharge.
Refrigerant flood back.
Improper piping or traps.
Verify proper piping slopes.
Contact factory.
Reheat flush cycle inadequate.
Refrigeration undercharged.
Dirty filter or evaporator coil.
Dirty or clogged condenser coil.
Check subcooling.
Check filter, coil and airflow.
Check coil and airflow.
Check equalized high side pressure with equivalent
outdoor temperature.
Air or other non-condensables in system.
Running cycle is
too long or unit
operates
Defective compressor.
Restriction in suction and liquid line.
Control contacts stuck.
Excessive load.
See “High suction pressure”.
continuously
Check for restrictions in refrigerant circuit.
Check wiring.
Add more equipment or reduce room load.
Too low of a system thermostat setting or
defective thermostat.
Adjust or replace thermostat.
Refrigerant undercharge.
High discharge pressure.
Adjust the charge by subcooling.
See “High discharge pressure”.
Liquid line
is too hot
Liquid line is
frosted or wet
Restriction in liquid line.
Clear restriction upstream of point of frosting.
Check airflow, check filters, check drive for loose
parts or belts.
Insufficient evaporator airflow.
Suction line
is frosting
Restriction in suction or liquid line.
Restriction upstream of point of frosting.
Check bulb of thermal expansion valve.
Check valve. If defective, replace.
Open valve.
Malfunctioning or defective expansion valve.
Hot gas bypass valve not functioning properly.
Manual hot gas bypass valve closed.
Frost on
evaporator coil
Always have a completed Pre Start-Up Checklist and Unit Start-Up Checklist prior to requesting parts or service information.
Model ERCH-HP Energy Recovery Unit
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3. Motors
Check for cleanliness
4. Fan Belts
Check for wear, tension, alignment
Routine Maintenance
DANGER
Electric shock hazard. Can cause injury or death.
Before attempting to perform any service or
maintenance, turn the electrical power to unit to OFF
at disconnect switch(es). Unit may have multiple
power supplies.
5. Blower Wheel & Fasteners
Check for cleanliness
Check all fasteners for tightness
Check for fatigue, corrosion, wear
6. Bearings
CAUTION
Lubricate per the schedule in the Fan Bearings
section
Use caution when removing access panels or other
unit components, especially while standing on a
ladder or other potentially unsteady base. Access
panels and unit components can be heavy and
serious injury may occur.
7. Door Seal
Check if intact and pliable
8. Wiring Connections
Check all connections for tightness
This unit requires minimal maintenance to operate
properly. To ensure proper operation and longevity, the
following items should be completed. The items in this
list assume a relatively clean air environment, and may
require attention more frequently in a dirty or dusty
area. If this unit contains an indirect gas heater, refer
to the Installation, Operation and Maintenance Manual
provided with the unit for maintenance purposes. A
Certified Technician should complete all refrigerant
systems checks.
9. Inspect all coils for cleanliness. Clean if required.
10. Inspect exterior and interior of entire unit for
surface rust. If rust is found, remove rust and coat
the blemished area with an appropriate protectant.
Heat Pump
An annual inspection of the heat pump system by a
licensed refrigeration mechanic is recommended.
1. Inspect entire heat pump for cleanliness.
2. Record performance data for volts, amps and water
temperature differences (both heating and cooling).
Maintenance Frequency:
3. Compare annual data to recorded start-up data.
Monthly
1. External Filter
Maintenance Procedures:
Lubrication
Check for cleanliness – clean if required
2. Internal Filter
Check all moving components for proper lubrication.
Apply lubrication where required. Any components
showing excessive wear should be replaced to maintain
the integrity of the unit and ensure proper operation.
Check for cleanliness – replace if required
3. Condensate Drain (if applicable)
Inspect and clean – refill with water
4. Bearings
Dampers
Lubricate per the schedule in the Fan Bearings
section
Check all dampers to ensure they open and close
properly and without binding. Backdraft dampers can
be checked by hand to determine if blades open and
close freely. Apply power to motorized dampers to
ensure the actuator opens and closes the damper as
designed.
Semiannually
1. Fan Belts
Check for wear, tension, alignment
2. Check for belt wear
Check pulley, bearings, and motor
Fan Belts
3. Bearings
Belts must be checked on a regular basis for wear,
tension, alignment, and dirt accumulation. Premature
or frequent belt failures can be caused by improper
belt tension (either too loose or too tight) or misaligned
sheaves. Abnormally high belt tension or drive
misalignment will cause excessive bearing loads and
may result in failure of the fan and/or motor bearings.
Conversely, loose belts will cause squealing on start-up,
excessive belt flutter, slippage, and overheated sheaves.
Both loose and tight belts can cause fan vibration.
Lubricate per the schedule in the Fan Bearings
section
Annually
It is recommended that the annual inspection and
maintenance occur at the start of the cooling season.
After completing the checklist, follow the unit start-
up checklist provided in the manual to ensure the
refrigeration system operates in the intended matter.
1. Lubrication
Apply lubrication where required
2. Dampers
Check for unobstructed operation
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When replacing belts on multiple groove drives, all belts
should be changed to provide uniform drive loading. Do
not pry belts on or off the sheave. Loosen belt tension
until belts can be removed by simply lifting the belts off
the sheaves. After replacing belts, insure that slack in
each belt is on the same side of the drive. Belt dressing
should never be used.
Fan Bearings
Most bearings are permanently lubricated and require
no further lubrication under normal use. Normal use
being considered -20ºF to 120ºF and in a relatively clean
environment. Some bearings are relubricatable and will
need to be regreased depending on fan use. Check your
bearings for grease zerk fittings to find out what type
of bearing you have. If your fan is not being operated
under normal use, bearings should be checked monthly
for lubrication. Shaft bearings are the most critical
moving part of a fan. Therefore, special attention
should be given to keeping the bearings clean and well
lubricated. Proper lubrication provides for reduction in
friction and wear, transmission and dissipation of heat,
extended bearing life and prevention of rust.
Do not install new belts on worn sheaves. If the sheaves
have grooves worn in them, they must be replaced
before new belts are installed.
The proper belt setting is the lowest tension at which
the belts will not slip under peak load operation. For
initial tensioning, set the belt deflection at 1/64-inch
for each inch of belt span (measured half-way between
sheave centers). For example, if the belt span is 64
inches, the belt deflection should be 1 inch (using
moderate thumb pressure at mid-point of the drive).
Check belt tension two times during the first 24 hours of
operation and periodically thereafter.
In order for a lubricant to fulfill these tasks, the proper
grease applied at regular intervals is required. Refer to
the recommended bearing lubrication schedule:
Bearing Lubrication Schedule
for Plenum Fans
(Relubrication Schedule in Months)
Belt Span
Deflection =
64
Shaft Diameter in Inches
Fan
RPM
1
⁄
2
to 1
6
6
11⁄8 to 11⁄2
15⁄8 to 17⁄8
115⁄16 to 23⁄16
To 250
500
6
6
6
6
6
5
750
6
5
4
3
1000
1250
1500
2000
2500
3000
4000
5000
6
5
5
5
4
4
3
2
4
3
2
1
.5
.5
.25
.25
3
2
1
1
.5
.25
.25
.25
2
1
1
.5
.25
.25
.25
.25
Belt Span
Fan Motors
Motor maintenance is generally limited to cleaning
and lubrication. Cleaning should be limited to exterior
surfaces only. Removing dust and grease buildup on
the motor housing assists proper motor cooling. Never
wash-down motor with high pressure spray. Greasing
of motors is only intended when fittings are provided.
Many fractional motors are permanently lubricated for
life and require no further lubrication.
If unusual conditions exist—temperatures below 32ºF or
above 200ºF, moisture or contaminants—more frequent
lubrication is required.
With the unit running, add grease very slowly with a
manual grease gun until a slight bead of grease forms at
the seal.
Fan Wheel and Fasteners
Wheels require very little attention when moving clean
air. Occasionally oil and dust may accumulate on the
wheel causing imbalance. When this occurs the wheel
and housing should be cleaned to assure smooth and
safe operation. Inspect fan impeller and housing for
fatigue, corrosion or wear.
Be careful not to unseat the seal by over lubricating
or using excessive pressure. A guide to the amount
of grease to be used is to fill 30% to 60% of available
space in the bearing and housing.
A high quality lithium based grease conforming to NLGI
Grade 2 consistency, such as those listed below should
be used:
Mobil 532
Mobilux #2
Routinely check all fasteners, set screws and locking
collars on the fan, bearings, drive, motor base and
accessories for tightness. A proper maintenance
program will help preserve the performance and
reliability designed into the fan.
Texaco Premium #2
Texaco Multifak #2
B Shell Alvania #2
Unirex 2
In addition to lubricating the bearings at specified
intervals, set screws in the bearing collars should be
checked for tightness. A bearing collar which has
loosened will cause premature failure of the fan shaft.
Fasteners attaching the bearings to the drive frame
should also be checked.
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Internal Filter Maintenance
Coil Maintenance
The unit will typically be provided with 2-inch, pleated
filters in the supply airstream. These filters should
be checked per a routine maintenance schedule
and replaced as necessary to ensure proper airflow
through the unit. Replacement filters shall be of same
performance and quality as factory installed filters. Filter
type must be pleated design with integral metal grid.
Two acceptable filter replacements are Aerostat Series
Coils must be cleaned to obtain maximum performance.
Check once a year under normal operating conditions
and if dirty, brush or vacuum clean. Soiled fins reduce
the capacity of the coil, demand more energy from the
fan, and create an environment for odor and bacteria to
grow and spread through the conditioned zone. High
pressure water (700 psi or less) may be used to clean
coils with fin thickness over 0.0095 inches thick. TEST
THE SPRAY PRESSURE over a small corner of the coil
to determine if the fins will withstand the spray pressure.
®
400 or Farr 30/30 .
Outdoor Air Filters: Access to the outdoor air filters
is through the door labeled as “Filter Access” on the
access side of the unit.
For coils with fragile fins or high fin density, foaming
chemical sprays and washes are available. Many coil
cleaners contain harsh chemicals, so they must be used
with caution by qualified personnel only. Care must be
taken not to damage the coils, including the fins, while
cleaning. Caution: Fin edges are sharp.
Refer to Subassemblies/Filters section for additional
information on filter locations.
WARNING
REFER TO GENERAL SAFETY INFORMATION
Do not operate make-up air ventilator without the
filters and birdscreens installed. They prevent the entry
of foreign objects such as leaves, birds, etc.
WARNING
Biological hazard. May cause disease. Cleaning
should be performed by qualified personnel.
Do not remove access panels or other unit
components while standing on a ladder or other
unsteady base. Access panels and unit components
are heavy and serious injury may occur.
Drain pans in any air conditioning unit will have some
moisture in them, therefore, algae and other organisms
will grow due to airborne spores and bacteria. Periodic
cleaning is necessary to prevent this buildup from
plugging the drain and causing the drain pan to
overflow. Inspect twice a year to avoid the possibility
of overflow. Also, drain pans should be kept clean to
prevent the spread of disease. Cleaning should be
performed by qualified personnel.
External Filter Maintenance
Aluminum mesh, 2-inch deep filters are located in the
supply weatherhood (if the weatherhood option was
purchased). Filters should be checked and cleaned
on a regular basis for best efficiency. The frequency of
cleaning depends upon the cleanliness of the incoming
air. These filters should be cleaned by rinsing with a mild
detergent in warm water prior to start-up.
Filters upstream of the coil should be checked
regularly. If the filters are dirty, they should be cleaned
or replaced. It is important that the coils stay clean to
maintain desired airflow.
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Maintenance Log
Date ___________________Time _____________ AM/PM
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Date ___________________Time _____________ AM/PM
Notes:___________________________________________
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Warranty
Greenheck warrants this equipment to be free from defects in material and workmanship for a period of one
year from the shipment date. The energy recovery wheel is warranted to be free from defects in material and
workmanship for a period of five years from the shipment date. Any units or parts which prove defective during
the warranty period will be replaced at our option when returned to our factory, transportation prepaid. Motors
are warranted by the motor manufacturer for a period of one year. Should motors furnished by Greenheck
prove defective during this period, they should be returned to the nearest authorized motor service station.
Greenheck will not be responsible for any removal or installation costs.
As a result of our commitment to continuous improvement, Greenheck reserves the right to change
specifications without notice.
Greenheck Catalog Energy Recovery Ventilator with Integral
Water Source Heat Pump, Model ERCH-HP, provides
additional information describing the equipment, fan
performance, available accessories, and specification data.
AMCA Publication 410-96, Safety Practices for Users and
Installers of Industrial and Commercial Fans, provides
additional safety information. This publication can be obtained
®
473501 • Model ERCH-HP IOM, Rev. 2, March 2012
Copyright 2012 © Greenheck Fan Corp.
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