Greenheck ERCH-20 Installation Manual
READ AND SAVE THESE INSTRUCTIONS
ENERGY RECOVERY UNIT
PART #468151
®
Model ERCH-20, 45, 55 & 90
without DDC Controls
INSTALLATION, OPERATION AND MAINTENANCE MANUAL
RECEIVING AND HANDLING
The ERCH is thoroughly inspected and test run at the factory. However, damage may occur
during shipping and handling. Upon delivery, inspect the unit for both obvious and hidden
damage. If damage is found, record all necessary information on the bill of lading and file a claim
with the final carrier. In addition, ensure all accessory items are present. Some accessory items
are stored inside the unit during shipping.
SAFETY WARNING
Improper installation, adjustment, alteration, service or maintenance can cause property damage,
injury or death. Read this installation, operation, and maintenance manual thoroughly before
installing or servicing this equipment. Installation and service must be performed by a qualified
installer, service agency, or the gas supplier.
WITH PACKAGED DX
INSTALLATION SUPPLEMENTS
Refer to the following installation supplements
ERCH supplied with Indirect Gas (IG) heating:
Model PVF, Indirect Gas Fired Furnaces
for Energy Recovery Units, Part #461006
ERCH Curb Assembly Instruction, Part #468280
SAVE THIS MANUAL
This manual is the property of the
owner, and is required for future
maintenance. This manual should
remain with each ERCH unit when the
job is complete.
TABLE OF CONTENTS
Storage and Owners Information ..........2
Basic Operation..........................3
Installation
Lifting .................................4
Unit Weights & Recommended Roof
Openings ............................4
Installation Concerns .....................5
Roof Curb Mounting ...................5-6
Rail Mounting and Ductwork Connections....6
Electrical Information.................. 7-8
Control Center Components ...............8
Service Clearances ......................9
Dimensional Data/Access Door Description . 10
Coil Applications & Drain Trap Info......11-12
Optional Accessories
Electric Heater Application/Operation ......13
Frost Control Application/Operation........14
Economizer Application/Operation .........15
Variable Frequency Drives ...............16
Typical Wiring Diagram ..................17
Sensors and Lights ..................18-19
Remote Control Panel & Wiring ........20-22
Sensors Mounted by Factory .............23
Energy Recovery Unit with Packaged DX
Start-Up Checklist
Unit ...............................24-26
Optional Accessories....................27
Fan ..................................28
Energy Recovery Wheel .................29
Routine Maintenance Checklist...........33
Belts and Motors .......................34
Blower Wheel and Fasteners .............34
Filters ................................35
Coil Maintenance ......................36
Energy Recovery Wheel Maintenance
Accessing Energy Recovery Wheel ........37
Removing Wheel Segments ..............37
Cleaning Wheel Segments ...............38
Parts List ..............................39
Sequence of Operation ...............40-41
Troubleshooting -Airflow .................42
Troubleshooting -General Unit .........43-44
Troubleshooting -Refrigeration Circuit ..45-50
Notes ..................................51
Warranty ...............................52
STORAGE
When a unit is not going to be in service for an extended amount of time, certain procedures should be followed
to keep the fans in proper operating condition.
•Rotatefanwheelmonthlyandpurgegreasefrombearingsonceeverythreemonths
•Coverunitwithtarptoprotectfromdirtandmoisture
(Note: do not use a black tarp as this will promote condensation)
•Energizefanmotoronceeverythreemonths
•Storebeltsflattokeepthemfromwarpingandstretching
•Storeunitinlocationwhichdoesnothavevibration
•Afterstorageperiod,purgegreasefromfanbearingsbeforeputtingfanintoservice
If storage of unit is in a humid, dusty or corrosive atmosphere, rotate the fan and purge the bearings once a
month. Improper storage which results in damage to the unit or components will void the warranty.
OWNER’S INFORMATION
The following summary highlights some important notes to help avoid premature failure and possible voidance
of warranty.
Product Overview
Greenheck ERCH Models integrated with a complete refrigerant system are designed with the purpose of being
a self-contained source for heating and cooling in both commercial and institutional applications. This is done in
a highly efficient manner through the use of a total enthalpy recovery wheel. The wheel allows the compressors
and cooling equipment to be downsized in the unit, therefore being more cost effective to operate. The DX
system comes fully charged from the factory with refrigerant and is ready for installation upon arrival.
The smaller tonnage units (4-9 tons) contain a single compressor, allowing for one stage of cooling. Larger units
(10-30 tons) come standard with two compressors. This allows for staging of compressors to meet a wider
range of outdoor air loads while reducing the amount of cycles per compressor.
Integral Components
All units are provided with an expansion valve, hermetic scroll compressor(s), liquid line filter drier, high
pressure manual reset cutout, low pressure auto-reset cutout, time delays for compressor protection, service/
charging valves, moisture indicating sight glass, and hot gas bypass. The compressors also come standard with
a crankcase heater for additional protection.
2
Energy Recovery Unit with Packaged DX
Shutdown Operation
The scroll compressors in this unit are designed to compress gas refrigerant only. To prevent liquid refrigerant
from migrating into and damaging the compressors, each compressor is supplied with a crankcase heater. Prior
to starting the compressors, the heaters must have power to them for 24 hours. Power should never be cut to
these units unless the complete shutdown procedure is followed.
Proper shutdown procedure:
1) Turn off main power supply to the unit
2) Turn thermostat controls to “off” position
3) Restore main power supply to the unit
4) Wait 24 hours prior to turning the thermostat control to the “on” position
Low Ambient Operation
Low ambient operation can cause damage to the refrigerant system. A factory-installed temperature sensor
in the outdoor air intake prevents refrigerant system operation at ambient conditions below 55ºF. Crankcase
heaters will still be engaged provided the main power has not been disconnected. If cooling is desired at
ambient temperatures below 55ºF, economizer operation (wheel start/stop or wheel modulation) should be
employed.
Reduced Airflow – Pumping oil and liquid refrigerant
Lack of maintenance will lead to filters, condensing coils, and evaporator coils building up with dirt and
debris. As this occurs, the airflow through the unit will decrease. Cooling coils are sized to handle a particular
airflow volume. A reduction in airflow can cause the cooling coils to get too cold and may result in excessive
liquid refrigerant return to the compressors. The liquid refrigerant buildup in the compressors will displace the
necessary oil required for proper lubrication. The combination of these two events will significantly reduce the
life of the compressors.
To maintain the proper airflow and system efficiency, follow all procedures in the Maintenance section.
Safety Listing
The ERCH units are listed per ANSI/UL 1995, Heating and Cooling Equipment, and bear the ETL logo.
Environmental Concerns
This equipment contains R22 or R-410a refrigerant. Refer to label on
access door identifying the type of refrigerant in the unit.
R22 is a class II refrigerant that contains HCFC’s. If released, HCFC’s
may reduce the amount of ozone in the atmosphere. This ozone
depletion will result in less protection from the sun and therefore it
is critical to use every precaution necessary to minimize the amount
admitted to our environment.
When working with Greenheck’s fully charged refrigerant system, it is
strongly recommended that caution is undertaken during installation,
operation, and routine maintenance. This caution will help ensure
that minimal amounts of refrigerant are leaked into the atmosphere.
To comply to the U.S. Clean Air Act, anytime there is residual
refrigerant, the proper equipment shall be used and methods should be followed to reclaim the refrigerant so
that it can be recycled, reprocessed, or destroyed.
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 a
qualified EPA Certified Technician.
IMPORTANT!
BASIC OPERATION
The ERCH with Packaged DX units bring in
fresh, outdoor air and remove stale, exhaust
air. Prior to discharging the exhaust air, the
energy recovery wheel transfers energy
from the exhaust air to the outdoor air at an
efficiency of 70-80%. Simply put, this unit
preconditions the outdoor air to save money
on heating and cooling costs. These particular
units also have packaged DX cooling and
heating options available after the recovery
wheel to further condition the fresh air.
Outdoor
Air
DX Cooling
Coil
Conditioned Air
sent to space
Energy Recovery Wheel
Optional
Heater
Exhaust Air
from building
3
Energy Recovery Unit with Packaged DX
CAUTION!
Unit is designed for Outdoor installation only. Follow all guidelines in this manual for proper installation.
INSTALLATION
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.
See Service Clearances/Access Panel Locations section for more details.
SAFETY 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.
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.
LIFTING
1) Before lifting, be sure that all shipping material has been
removed from unit.
2) To assist in determining rigging requirements, weights are
shown below.
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.
UNIT WEIGHTS & RECOMMENDED ROOF OPENING
Unit
Size
ERCH-20 2150 46 46
ERCH-45 3500 54 48
ERCH-55 4450 65 58
ERCH-90 6200 85 63
Unit weights assume rooftop configuration with weatherhoods, filters,
outdoor air damper, six row DX coil, integral condensing section and
an indirect gas fired furnace.
Approximate
Weight (lbs)
U
(inches)V (inches)
Lift using lifting lugs
and spreader bar
V
EXHAUST
INTAKE
SUPPLY
DISCHARGE
1/2 inch
U
1/2 inch
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.
4
Energy Recovery Unit with Packaged DX
INSTALLATION CONCERNS
Unobstructed airflow to the condensing section must be maintained at all times to ensure proper operating
efficiency and capacity of the cooling system. Unit placement should allow proper airflow over the condensing
section. The unit may not operate properly and damage may occur to the system if there is coil starvation (lack of
air over condenser) or warm air recirculating back through the condensing coil. Recirculating air is caused when
the unit is placed near obstacles that can redirect exhaust air from the condensing fans, back around to the coil
inlet. Overhangs or walls near the condensing section are two examples.
Another consideration when placing the unit is prevailing wind direction. The condensing coil operation can be
significantly affected when winds are blowing continuously and directly at the condensing coil. On hot days, the
wind will help the system by providing extra flow over the coil. But on cooler days, that same wind may overcool
the refrigerant, and cause hot gas bypass to operate more frequently, causing higher operating costs. Therefore,
avoiding direct winds will provide a more stable operation of the system throughout the cooling season.
Lack of air over the coil can reduce efficiencies and affect system operation. Do not allow debris (such as leaves
and trash), to accumulate on or near the unit. Keeping debris clear of the unit will ensure minimal obstruction to
the coils, keeping efficiencies and operation closer to design. The unit typically should not operate when snow
is present. In the event this is possible, make sure all snow is clear of the coil and condensing fans prior to
operating the unit.
If more than one unit is being installed, make provisions so discharge air from either the condensing fans or
exhaust fan of the unit do not discharge towards another unit’s intake. Also, OA intake and condensing sections
should be spaced as too allow proper airflow to each unit helping ensure the units operate as intended.
When cutting only duct openings, cut opening 1 inch (25mm) larger than duct size to allow clearance for
installation. Area enclosed by roof curb must comply with clearance to combustible materials. If the roof is
constructed of combustible materials, area within the roof curb must be ventilated, left open, or covered with
non-combustible material which has an “R” value of at least 5. If area within curb is open, higher radiated sound
levels may result.
Where the supply or warm air duct passes thru a combustible roof, a clearance of one inch must be maintained
between the outside edges of the duct and combustible material in accordance with NFPA Standard 90A.
ROOF CURB MOUNTING
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.
1. 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.
2. Install Curb
Locate curb over roof opening and fasten in place. (Refer
to Recommended Roof Openings). 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.
3. 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.
4. 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.
Roof curb details, including
duct location dimensions, are
available on ERCH roof curb
assembly instructions,
Part #468280.
Curb Outside Dimensions and Curb Weights (lbs)
Model L W Weight
ERCH-20 104.88 51 310
ERCH-45 115.75 60.63 400
ERCH-55 129.88 71.5 510
ERCH-90 148.13 90.75 720
All dimensions shown are in inches. Weights are for 12 inch high curbs.
Curb Outside Dimensions
5
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Length of Straight Duct
GOOD
POOR
GOODPOOR
Tu rning
Vanes
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GOODPOOR
Tu rning
Vanes
ROOF CURB MOUNTING - CONTINUED
SIDE OF UNIT
BASE
A
B
C
D
E
1 INCH INSULATION
ERCH-20 2.00 2.00 1.00 0.88 0.75
ERCH-45 2.00 4.25 2.00 1.31 0.50
ERCH-55 2.00 4.25 2.00 1.31 0.50
ERCH-90 2.00 4.25 2.00 1.31 0.50
ROOF CURB
All dimensions shown are in inches.
Curb Cap Details for Factory Supplied Roof Curbs
RAIL MOUNTING
Rail Layout
• RailsdesignedtohandletheweightoftheERCHshouldbe
positioned as shown on the diagram (rails by others).
• Makesurethatrailpositioningdoesnotinterferewiththesupply
air discharge opening or the exhaust air intake opening on the
ERCH unit. (Avoid area dimensioned “B” below).
• Railsshouldrunthewidthoftheunitandextendbeyondtheunit
a minimum of 12 inches on each side.
• Setunitonrails.
Model
Energy Recovery Unit with Packaged DX
Curb Cap Dimensions
A B C D E
Isometric view of unit on rails
Rail
OUTDOOR AIR
INTAKE HOOD
Model
Mounting
A B
SUPPLY/EXHAUST
OPENING
B A
Side view of unit on rails
DUCTWORK CONNECTIONS
Examples of good and poor fan-to-duct connections are shown below. Airflow out of the fan should be directed
ERCH-20 5.00 41.00
ERCH-45 7.00 41.90
ERCH-55 5.50 53.00
ERCH-90 6.00 59.00
All dimensions shown are in inches.
straight or curve the same direction as the fan wheel rotates. Poor duct installation will result in low airflow and
other system effects.
n
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Recommended Discharge Duct Size and Length
Model Blower Size Duct Size Straight Duct Length
ERCH-20 9 14 x 14 36
ERCH-45 12 20 x 20 48
ERCH-55 15 28 x 28 60
ERCH-90 18 32 x 32 60
All dimensions shown are in inches.
• Recommendedductsizesarebasedonvelocitiesacrossthecfmrangeofeachmodelatapproximately800feetperminute(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.
• Straightductlengthswerecalculatedbasedon100%effectiveductlengthrequirementsasprescribedinAMCAPublication201.
Calculated values have been rounded up to nearest foot.
6
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Energy Recovery Unit with Packaged DX
OUTDOOR AIR WEATHERHOOD
Outdoor air weatherhood will be factory mounted.
EXHAUST WEATHERHOOD
The exhaust weatherhood is shipped separately as a kit with its own instructions.
DAMPERS
Backdraft dampers are always included as an integral part of the exhaust hood
assemblies. Motorized outdoor air and exhaust air dampers are optional and are
factory mounted (and wired) at the intake.
ELECTRICAL INFORMATION
The unit must be electrically grounded in accordance with the current National Electrical Code, ANSI/NFPA 70.
In Canada, use current CSA Standard C22.1, Canadian Electrical Code, Part 1. In addition, the installer should
be aware of any local ordinances or electrical company requirements that might apply. System power wiring
must be properly fused and conform to the local and national electrical codes. System power wiring is to the
unit main disconnect (door interlocking disconnect switch standard on most units) or distribution block and
must be compatible with the ratings on the nameplate: supply power voltage, phase, and amperage (Minimum
Circuit Amps - MCA, Maximum Overcurrent Protection - MOP). All wiring beyond this point has been done by
the manufacturer and cannot be modified without affecting the unit’s agency / safety certification.
If field installing an additional disconnect switch, it is recommended that there is at least four feet of service
room between the switch and system access panels. When providing or replacing fuses in a fusible disconnect,
use dual element time delay fuses and size according to the rating plate.
Field Power Connection: Electronic wiring is run through the roof of the unit. All power and control
connections should be run through the floor or side panel.
If power supply is desired through bottom of unit, run the wiring through the curb, cut a hole in the cabinet
bottom, and wire to the disconnect switch. Seal penetration in cabinet bottom to prevent leakage.
The electric supply to the unit must meet stringent requirements for the system to operate properly. Voltage
supply and voltage imbalance between phases should be within the following tolerances. If the power is not
within these voltage tolerances, contact the power company prior to operating the system.
Voltage Supply - See voltage use range on the rating plate. Measure and record each supply leg voltage at all
line disconnect switches. Readings must fall within the allowable range on the rating plate.
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.
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)
Formula: % Voltage Imbalance = [100 x (VA-VD)] / VA
CAUTION
If any of the original wire as supplied with the appliance must be replaced, it must be
replaced with wiring material having a temperature rating of at least 105ºC.
WARNING
To prevent injury or death due to electrocution or
contact with moving parts, lock disconnect switch
open.
Most factory supplied electrical components are pre-wired. To
determine what electrical accessories require additional field wiring,
refer to the unit specific wiring diagram located on the inside of the
unit control center access door. The low voltage control circuit is
24 Vac and control wiring should not exceed 0.75 ohms. Refer to
Field Control Wiring Length/Gauge table for wire length maximums
for a given wire gauge. 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.
For units with a gas furnace, if you turn off the
power supply, turn off the gas.
WARNING
Field Control Wiring Length/Gauge
Total Wire Length Minimum Wire Gauge
125 ft. 18
200 ft. 16
300 ft. 14
450 ft. 12
7
Energy Recovery Unit with Packaged DX
If wire resistance exceeds 0.75 ohms, an industrial-style, plug-in 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
(refer to Typical Control Center Components). 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.
Note: Standard factory installed electric post-heaters have their own disconnect separate from the unit
disconnect. Thus, each electric post-heater requires its own separate power connection.
CONTROL CENTER COMPONENTS
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
7. Fuses for blower motors
8. Grounding lug
9. Distributor block
10. Compressor fuse blocks
11. Compressor contactors
12. Condensing fan contactors
13. Compressor cycle timers
14. Compressor relay
15. Terminal block
Optional Control Center Components
16. DDC controller
17. Dirty filter pressure switches
18. Economizer module
19. Thermostats for:
- Economizer module
- Energy Recovery wheel frost
control
- Compressor lock out
20. Terminal block
21. Frost control pressure switch
22. Energy recovery wheel VFD
3
22
8
1 5
7
9
6
21
20
Component #6
19
Exploded Detail
of Terminal Strip
4
18
Refer to “Refrigeration
System” section for
components in compressor
2
compartment
Access to Control Center
17
Components is gained through
the access panel indicated.
16
10
11
12
13
14
15
8
Energy Recovery Unit with Packaged DX
SERVICE CLEARANCES / ACCESS PANEL LOCATIONS FOR MODEL ERCH
Clearances must be maintained on all
sides of this unit. This especially is true
with the top of this unit. Hot air is being
discharged through the condensing
fans during operation, and the more
clearance available, the better the
chance of avoiding recirculation or coil
starvation. This unit should never be
placed under an overhang or inside a
building. A minimum of 48 inches over
the condensing fans is recommended.
ERCH-20, 45, 55, and 90 units require
minimum clearances 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 recovery 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-20
ERCH-45
36 IN
ACCESS PANEL
EXHAUST
HOOD
HOOD
OUTDOOR AIR
FILTERS
36 IN
WHEEL CASSETTE
ACCESS PANEL
FILTERS
COIL
SECTION
ACCESS PANEL
ELECTRICAL BOX
EXHAUST AIR
INTAKE
ACCESS PANEL
ACCESS PANEL
IG HEATER
Minimum 48 inches
clearance
Minimum 12 inches
clearance
Condensing Coil Intake
Keep this area clear
52 IN
CLEARANCE
WITH IG HEATER
12 IN
MINIMUM
ERCH-55
ERCH-90
ACCESS PANEL
*48 IN
ACCESS PANEL
**64 IN
ACCESS PANEL
Clearances for service and component removal on ERCH-20 and ERCH-45
* Clearance for energy wheel removal on ERCH-20
** Clearance for energy wheel removal on ERCH-45
FILTERS
42 IN
ACCESS PANEL
ACCESS PANEL
WHEEL CASSETTE
FILTERS
COIL
SECTION
ACCESS PANEL
ACCESS PANEL
ELECTRICAL BOX
EXHAUST AIR
INTAKE
42 IN
ACCESS PANEL
ACCESS PANEL
ACCESS PANEL
WITH IG HEATER
IG HEATER
52 IN
CLEARANCE
42 IN
ACCESS PANEL
EXHAUST
HOOD
HOOD
OUTDOOR AIR
12 IN
MINIMUM
Clearances for service and component removal on ERCH-55 and ERCH-90
9
Energy Recovery Unit with Packaged DX
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F
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DIMENSIONAL DATA / ACCESS DOOR DESCRIPTIONS AND LOCATIONS
Model
A B C D E F G H I J
Exterior Dimensions
ERCH-20 108 50 56 27 28.5 17 6 14.25 18 18
ERCH-45 119 69 66 38 41 23.375 10.5 13.375 20 16
ERCH-55 133.5 70 76 39 59.5 5.875 7.125 21.25 25 16
ERCH-90 151.5 85 96 46 78 2.875 10 24.5 27 16
All dimensions shown are in inches.
Overall Exterior Dimensions
Model
(including Lifting Lugs)
Width
Overall Width
(with Exhaust Hood)
Overall Length
(with Outdoor Air Hood)
ERCH-20 59.5 75 116
ERCH-45 69.5 86 122
ERCH-55 79.5 101 134
ERCH-90 99.5 123 147
All dimensions shown are in inches.
Following is a list of items accessible through the access doors shown on the diagrams. Some items are
optional and may not have been provided.
1. Exhaust blower, motor, and drives
2. Aluminum mesh filters (intake hood)
3. Energy recovery wheel, motor, belt, and seals
Outdoor air filters
Outdoor air intake damper (optional)
Electric preheater (optional)
Frost control sensors (optional)
Economizer sensors (optional)
4. Coil access / Drain pan
5a. Outdoor air blower, motor, and drives
(with indirect gas furnace)
6. Control center
All electrical controls
VFD for energy recovery wheel (optional)
7. Exhaust air filters
Exhaust air intake damper (optional)
8. Electric post-heater control center (optional)
9. Bypass damper (optional)
10. Condensing fan motors
11. Compressor(s) - refer to Refrigeration System
section for components in compressor
compartment
Drain Pan
5b. Outdoor air blower, motor, and drives
(without indirect gas furnace)
Coil access / Drain pan (w/o Electric Heat)
Model ERCH with Packaged DX
10
5a
10
5b
11
6
7
8
9
4
3
1
2
Energy Recovery Unit with Packaged DX
COIL APPLICATION RECOMMENDATIONS
Factory installed cooling and heating components are mounted
in the coil section of the unit. The coil section is downstream
of the energy wheel on the supply air side of the unit.
Note the coil connection locations on the picture. Coil
connections are located external to the unit as shown. Coil
connections that are not external have been ordered from the
factory with interior or exhaust airstream coil connections.
Hot
water coil
connections
Coil access door
Note: DX coil liquid connection is internal to units.
WATER COILS
1. Piping should be in accordance with accepted industry
standards. Pipework should be supported independently
of the coils. Water connections are male NPT iron pipe.
When installing couplings, do not apply undue stress to the
connection extending through the unit. Use a backup pipe wrench to avoid breaking the weld between coil
connection and header.
2. Connect the WATER SUPPLY TO THE BOTTOM CONNECTION on the air leaving side and the WATER
RETURN TO THE TOP CONNECTION on the air entering side. To insure proper venting, an external air vent
in the piping is recommended. Connecting the supply and/or return in any other manner will result in very
poor performance. Be sure to replace factory installed grommets around coil connections if removed for
piping. Failure to replace grommets will result in water leakage into the unit and altered performance.
3. The air vent at the uppermost point should be temporarily opened during system start-up to release all of the
air from the coil. To maintain heat transfer capacity, periodically vent any air in coil.
4. Water coils are not normally recommended for use with entering air temperatures below 40ºF; however,
the energy recovery wheel maintains a pre-coil temperature higher than 40ºF. No control system can be
depended on to be 100% safe against freeze-up with water coils. Glycol solutions or brines are the only safe
media for operation of water coils with low entering air conditions.
CONTINUOUS WATER CIRCULATION THROUGH THE COIL AT ALL TIMES IS HIGHLY RECOMMENDED.
5. Pipe sizes for the system must be selected on the basis of the head (pressure) available from the circulation
pump. The velocity should not exceed 6 feet per second and the friction loss should be approximately 3 feet
of water column per 100 feet of pipe.
DIRECT EXPANSION (DX) COILS WITH INTEGRAL CONDENSING SECTION
1. The condensate drain pipe should be sized adequately to ensure the condensate drains properly. Refer to
Drain Trap section.
11
Energy Recovery Unit with Packaged DX
DRAIN TRAP
Cooling coils are provided with a stainless steel drain pan
with 1-inch male NPT drain connection. A drain trap must be
connected to the drain connection to allow excess water to
flow out of the drain pan. More importantly, though, due to the
negative internal static of the cooling coil compartment, installing
the drain trap prevents outdoor air from being pulled into the
drain pan and consequently forcing water out of the pan and into
the unit.
To ensure the drain trap works properly, the trap height must
account for the difference in static pressure between ambient
conditions outside the unit and the internal negative pressure of the cooling coil compartment. For energy
recovery units, an assumption of 3.0 in. wg differential will be sufficient. This would require a trap design as
shown. If the internal static is believed to be higher, consult factory.
Refer to local codes to determine drainage requirements. If draining onto to roof, place a drip pad below drain
to protect roof. If draining onto roof is not acceptable, a drain line must be attached to the trap. The drain line
must be pitched away from the unit at least 1/8-in. per foot. On longer runs, an air break should be used to
ensure proper drainage. Local codes may require drainage into a waste water system.
Drainage problems not only occur from improper drain trap design, but also from lack of maintenance of the
cooling coil compartment. Algae can form in the drain pan and trap and cause reduced water flow, which can in
turn result in backup into the system. Regular maintenance will prevent this from occurring. If the drains have a
cleanout opening, be sure to close the opening after cleaning.
4 in.
2 in.
12
Energy Recovery Unit with Packaged DX
OPTIONAL ACCESSORIES
Electric Heater Application/Operation
Factory installed electric heaters can be provided for preheat and/or post-heat. An electric preheater warms
the outdoor air prior to the energy recovery wheel to prevent frosting on the wheel. An electric post-heater
warms the air leaving the energy recovery wheel to a user specified discharge temperature. Electric heaters are
available in 208, 230, or 460 Vac (refer to heater nameplate for voltage).
Preheaters: Preheaters are standard as 2-stage, step control. Step control heaters are designed with
multiple stages made up of equal increments of heating capability. For example, a 10 kW
heater with two stages will be composed of two 5-kW stages. Preheaters are single point
wired at the factory. A temperature sensor (with field adjustable set point) is mounted in the
outdoor airstream after the preheater to turn the preheater on. See Frost Control Application
/Operation for typical set points. If the temperature falls below the set point and the wheel
pressure drop sensor is triggered, the first stage of the preheater will turn on. If the first stage
does not satisfy the set point, the second stage will also turn on.
Post-heaters: Post-heaters are standard as SCR control. Post-heaters are not single point wired (see
Electrical Connections). A temperature sensor (with field adjustable set point) is mounted in
the outdoor airstream after the post-heater to turn the post-heater on. A SCR heater provides
an infinitely modulating control of the heat to provide an accurate discharge temperature. A
call for heat is required.
Electric Preheater
The pre-heater is single
point wired to the ERCH
control center. Access
to the preheater control
panel is through the
supply filter door.
DX
Cooling Coil
Post-Heater Control Panel
The post-heater is not single point
wired to the ERCH control center.
Separate power must be supplied to
the post-heater disconnect (located
in unit control center).
See ’Access Door Descriptions and
Locations’ for access to post-heater
control panel. For Model ERCH, the
exhaust filters must be removed
from the unit to access.
Electric
Post-Heater
13
Energy Recovery Unit with Packaged DX
OPTIONAL ACCESSORIES
Frost Control Application/Operation
Extremely cold outdoor air temperatures can cause moisture condensation and frosting on the energy recovery
wheel. Frost control is an optional feature that will prevent/control wheel frosting. Three options are available:
1) Timed Exhaust frost control
2) Electric preheat frost control
3) Modulating wheel frost control
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
wheel. The typical temperature setting corresponds to the
indoor air relative humidity as shown in the Frost Threshold Temperatures Table and 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 & C in the control center will notify personnel when unit is in frost control mode (refer to Remote Panel Wiring
schematics section for wiring details). The following explains the three options in more detail.
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 energy recovery wheel. Default factory settings are 5 minutes off and 30
minutes on. Use the following test procedure for troubleshooting.
Testing (refer to diagram at right)
• Jumperthewheelpressureswitchintheunitcontrolcenter.Setthe
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)
• Turnthetemperaturesensorupashighaspossible.Thesupplyblower
should cycle on for one minute, then turn off for one minute.
• Aftertesting,settheTimer Scale as follows: T1 = 10 minutes, T2 =
1 hour
• SettheTimer 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.
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. (Refer to Electric Heater
Application/Operation for electric preheater location). 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.
Testing
• Turnthethermostatashighasitwillgoandjumperthewheelpressuresensor.Theheater
should turn on.
• Ifitdoesn’t,eitherputtheoutdoorairsidedoorsonortemporarilyjumpertheairflowpressure
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 fieldadjustable (refer to VFD section for more information). The variable frequency drive will be fully programmed at
the factory.
14
Indoor RH @ 70°F Frost Threshold Temp
20% -10º F
30% -5º F
40% 0º F
Frost Threshold Temperatures
A1 B1 15
0.60.8
0.41.0
T2
Timer
Scale
T1
0.20
T21 MIN
T11 MIN
0.60.8
0.41.0
0.20
16 18 A2
Timer
Dip
Switch
Energy Recovery Unit with Packaged DX
OPTIONAL ACCESSORIES
Economizer Application/Operation
The energy recovery wheel operation can be altered to take advantage of economizer operation (free cooling).
Two modes are available: 1) De-energizing the wheel or 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.
Testing
Temperature Sensor with Override
• TurnbothTemperatureandOverridethermostatsdownaslowastheygo.The
wheel should be rotating.
• TurntheTemperaturesensorupashighasitgoes,andkeeptheOverride
sensor as low as it will go. The wheel should stop rotating.
• Turnbothsensorsashighastheywillgo.Thewheelshouldstartrotating.
• SettheTemperaturesensoratdesiredpointforeconomizeroperationtobegin.
Set the Override sensor at desired point for economizer operation to end
(factory default is 65ºF and 50ºF, respectively).
Enthalpy Sensor with Override
• Turnunitpoweroff.DisconnectC7400solidstateenthalpysensorfromterminal
So on the enthalpy controller. Also, disconnect the 620 ohm resistor from
terminal Sr on the enthalpy controller. Turn unit power on. The LED on the
enthalpy controller should light and the energy recovery wheel should not rotate.
• Turnunitpoweroff.Reconnect620ohmresistortoterminalSrontheenthalpy
controller. Turn unit power on. The LED on the enthalpy controller should not
light and the energy recovery wheel should energize and rotate.
If the steps above provide the results described, the enthalpy economizer is
working properly.
• Turnunitpoweroff.ReconnectC7400solidstateenthalpysensor
to terminal So.
Temperature Sensor
with Override
Enthalpy Sensor
with Override
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
Enthalpy
Controller
winter. The speed of the energy wheel will be controlled in response to
the discharge temperature set point.
Sequence of Operation:
The variable frequency drive is fully programmed at the factory (refer to VFD section
for more information). 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:
TOA > T
RA
TOA < TRA and TOA > T
TOA < TRA and TOA < T
: Wheel runs at full speed (maximum energy recovery)
: Wheel is stopped (no energy recovery)
SA
: Wheel will modulate to maintain discharge temperature
SA
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.
15
Energy Recovery Unit with Packaged DX
OPTIONAL ACCESSORIES
Variable Frequency Drives for Energy Recovery Wheel
Factory installed VFD for the energy recovery wheel are programmed at the factory per the settings shown
below. Refer to the instruction manual that ships with the unit when making adjustments. A copy of the manual
can be found online at www.drives.com. For technical support, contact Yaskawa direct at 1-800-927-5292.
Yaskawa GPD-305 Drive
Parameter Setting
n01 Access Level 1
n30 Ref Upper Limit 100% or 66%*
n32 Motor Rated FLA Motor FLA
n33 Elect Thermal Overload 1
n36 Multi-Function input (terminal S2) 10
n40 Multi-Function output (MA,MB,MC) 4
n41 Analog Freq. Reference Gain 0
n42 Analog Freq. Reference Bias 99
n46 Carrier Frequency 2
n58 Frequency Detection Level 20
n01 Access Level 0
*36 inch wheel is 66% (40Hz). All other wheels are 100% (60Hz).
16
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