PART #461248
READ AND SAVE THESE INSTRUCTIONS
HEAT RECOVERY UNIT
WITH EVAPORATIVE COOLING
®
Models:
HRE-20, 45, 55, & 90
INSTALLATION, OPERATION AND MAINTENANCE MANUAL
**WARNING**
DISCONNECT AND SECURE TO THE "OFF" POSITION ALL ELECTRICAL POWER TO THE UNITS
PRIOR TO INSPECTION OR SERVICING. FAILURE TO COMPLY WITH THIS SAFETY PRECAUTION
COULD RESULT IN SERIOUS INJURY OR DEATH.
**IMPORTANT**
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.
Indirect Evaporative Cooler
(Exhaust/Scavenger Airstream)
Direct Evaporative Cooler
(Outdoor/Supply Airstream)
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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.
Lift using lifting
lugs and
See pages 6 and 7 for more detail on appropriate
clearances.
spreader bar
LIFTING
Units must be lifted as it ships from the factory. All
units are equipped with lifting lugs. THE USE OF ALL
LIFTING LUGS IS MANDATORY WHEN LIFTING.
Lifting should only be done with all access doors
closed to avoid damaging the unit. To prevent
damage to the unit cabinetry, use spreader bars.
Spreader bars must be in position to stop cables from
rubbing the frame or panels. Before hoisting into
position, test lift to insure stability and balance. Avoid
twisting or uneven lifting of the unit. Never lift units by
weatherhoods.
FIGURE 1
UNIT WEIGHTS (dry weights)
Unit Size Approx. Weight (lbs)
HRE-20
HRE-45
HRE-55
HRE-90
1500
2300
3000
5000
V
RECOMMENDED ROOF OPENING
Model
U
V
EXHAUST
INLET
HRE-20
HRE-45
HRE-55
HRE-90
46
54
65
85
37
39
47
49
U
SUPPLY
OUTLET
All dimensions shown are in inches.
FIGURE 2
3
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ROOF CURB MOUNTING
1. Factory Supplied Roof Curbs
Roof curbs are Model GKD, which are shipped in a
knockdown kit and require field assembly (by
others). Assembly instructions are included with
the curb.
2. Cut Roof Opening and Locate Curb
Layout the unit roof opening such that the supply
discharge & exhaust inlet of the unit will line up
with the corresponding ductwork (refer to
Recommended Roof Openings on page 3). Be
sure to allow for the recommended service
clearances. Keep the supply inlet of the unit away
from any other exhaust fans.
3. Install Curb
Locate curb over roof opening and fasten in place.
Check that the diagonal dimensions are within
1/8 inch of each other and adjust as necessary.
Shim as required to level. Lower unit onto curb by
following the LIFTING instructions on page 3 of
this manual. Note,
roof curbs fit inside
the unit base.
Curb Outside Dimensions
Model
L
W
4. Install Duct Work
Installation of all
HRE-20
HRE-45
HRE-55
HRE-90
93
51
L
100.5
112.75
60.63
71.5
W
ducts should be
done in accordance
with SMACNA and
AMCA guidelines.
125.75 90.75
FIGURE 3
All dimensions shown are in inches.
DUCT WORK CONNECTIONS
Examples of good and poor fan-to-duct connections are shown below (See FIGURE 4). Airflow out of the fan
should be directed straight or curve the same direction as the fan wheel rotates. Poor duct installation will result
in low airflow and other system effects.
n
o
i
t
n
o
i
t
Length of Straight Duct
a
t
a
t
o
o
R
R
GOOD
POOR
FIGURE 4
SUPPLY WEATHERHOOD
Supply weatherhood will be factory mounted.
EXHAUST WEATHERHOOD
The exhaust weatherhood is shipped separately as a kit with its own instructions.
EXHAUST DAMPERS
Backdraft dampers for exhaust discharge are mounted in the unit. Motorized dampers are shipped loose (inside
HRE) and must be field installed.
4
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INSTALLATION (continued)
ELECTRICAL CONNECTIONS
The electrical supply must be compatible with that shown on the nameplate: voltage, phase, and amperage
capacity. The electrical supply line must be properly fused and conform to local and national electrical codes.
All internal electrical components are pre-wired at the factory. Field electrical connections only need to be made
inside the unit to the main disconnect (See FIGURE 5, Item #1) and the 24 volt control circuit (See FIGURE 5,
Item #7). A door interlocking safety disconnect is provided as standard feature.
Note: Standard factory installed electric post heaters have their own disconnect separate from the unit
disconnect. Thus, electric post heaters require a separate power connection.
IMPORTANT:
Use minimum 14 ga. wire for 24 volt control power.
Control wire resistance should not exceed 0.75 ohms (approximately 285 feet total length for
14 ga. wire; 455 feet total length for 12 ga. wire). 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 (between terminal blocks 2 and 3 on the control strip — See FIGURE 5,
Item #7). 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.
TYPICAL CONTROL CENTER COMPONENTS
1. Main Disconnect
2. Motor Starter — Exhaust/Scavenger
Air Fan
3. Motor Starter — Outdoor Air Fan
4. Motor Contactor — Energy Wheel
5. Control Power Transformer
(24 VAC Secondary)
6. Energy Wheel Motor Transformer
(230 VAC Secondary)
(for HRE-20 & HRE-45 units with
primary voltage greater than 230 Vac)
7. 24 VAC Terminal strip
1
8
5
6
8. Fuses for the control circuit, wheel
drive transformer, and blower
motors.
7
4
Control Center
O
f
f
On
3
2
Main
Disconnect
Intake
Hood
FIGURE 5
Exhaust
Hood
5
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SERVICE CLEARANCES / ACCESS PANEL LOCATIONS for Model HRE
HRE-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 FIGURES 6 and 7 below for these dimensions.
Clearances for service and component removal on HRE-20 and HRE-45
36 in.
Exhaust
Hood
Access Panel
Electrical Box
36 in.
Indirect
Evap
Section
0 in.
Exhaust Air
Intake
Clearance without
IG Heater
52 in.
Clearance with
IG Heater
Direct
Evap
Section
Access Panel
*48 in. **64 in.
TOP VIEW
*Clearance for energy wheel removal on HRE-20.
**Clearance for energy wheel removal on HRE-45.
FIGURE 6
Clearances for service on HRE-55 and HRE-90
42 in.
Exhaust
Hood
Access Panel
Electrical Box
42 in.
Indirect
Evap
Section
0 in.
Exhaust Air
Intake
Clearance without
IG Heater
52 in.
Clearance with
IG Heater
Direct
Evap
Section
Access Panel
42 in.
TOP VIEW
FIGURE 7
6
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Evaporative Cooling Modules
Indirect Evaporative Cooler
(Exhaust/Scavenger Airstream)
It is important to mount the heat recovery unit level to
ensure proper operation and water drainage. Piping
should be of adequate size to provide sufficient
supply of water to meet the maximum demand of the
evaporative coolers.
Evap Module Start-Up
1. After the energy recovery unit is set in place, run
the overflow and drain lines to the exterior fittings
on the evaporative cooler (drain & overflow
connections at unit are 3⁄4-inch female pipe thread).
The supply line can be attached at the
downstream side of the evaporative cooler. A
manual shut off valve should be mounted in the
supply line near the unit for servicing purposes.
Also, a trap should be installed in the drain line to
prevent sewer gas from being drawn into the unit
(see Figure 8).
Direct Evaporative Cooler
(Outdoor/Supply Airstream)
2. The cooler will be prewired by the factory.
6. After the media break-in period, the water flow
rate over the media needs to be checked. The
pumps should provide enough water to saturate
the media in 1-3 minutes. If adequate flow rate is
not achieved, consult with the factory.
3. Check to make sure that the pump filter is around
the pump inlet.
4. Turn the water on and allow the pan to fill up with
water. The float should be adjusted to provide 2
inches of water depth in the sump.
7. The water bleed-off rate will now need to be
adjusted. This measurement is 3 to 6 percent of
the media flow rate. The recommended flow rate is
11⁄2 to 2 GPM per
5. Saturate the media without any airflow through the
unit. A jumper wire is required on the terminal strip
to provide power to the evaporative cooler pump
(see the wiring diagram for the proper location).
This saturation process will break-in the media and
minimize the odors associated with the media. The
media’s break-in period should be no less than 20
minutes. When the process is complete, remove
the jumper wires in the control center.
Unit Size Media Pad Top Area
square foot of
HRE-20
HRE-45
HRE-55
HRE-90
1.5 ft2
2 ft2
2.5 ft2
3.3 ft2
media pad top area
(see table at right).
After the unit has
been installed and
running for two
weeks the unit should be checked for mineral
deposits. If there are deposits, the bleed-off rate
needs to be increased. Some areas of the country
have water with greater amounts of dissolved
minerals requiring a higher bleed-off rate.
Note: Evaporative media may foam for a short
period following the initial start-up. Leave
the bleed-off valve fully open until the
foaming stops.
8. Verify that both airflow and system static pressure
are in agreement with the specifications. If these
conditions are met, check for water carry over
from the discharge side of the media. If carry over
is observed, check the distribution header for
holes or tears and the
Side of HRE Unit
Drain Line
Evaporative
Cooling
water standoff tube for
blockage.
Overflow
Media
Sump
Trap
9. After all final
Manual
Shutoff
Valve
adjustments are made,
remove the jumper
wires and replace all
Drain
Line
Roof Curb
access panels. The
unit is now ready for
operation.
Roof Line
Manual Shutoff Valve
Supply Line
FIGURE 8
7
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WATER CONTROL OPTIONS FOR EVAPORATIVE COOLING
Auto Drain and Fill with Freeze Protection
This system will automatically drain the sump tank and fill it with fresh water at the field adjustable intervals,
typically once every 24 hours. This flushes mineral build-up and debris from the tank to promote low
maintenance and increase media pad life. In addition, the system will protect the evaporative cooler from
freezing by draining the sump tank and supply line when the outside temperatures fall below the set point of the
outside air sensor. Typically, this is set at 45º to 50º F. The auto drain and fill control box should be installed in
an area that is shaded from direct sunlight so the outside air sensor probe will detect an accurate air
temperature.
Plumbing (see FIGURE 9)
1. Run water supply line to the unit and install Water Supply Solenoid Valve (A) in this line as close to the water
source as possible.
2. Install Drain Solenoid Valve (B) in the supply line as indicated below. From the outlet on the drain valve, run line
to a suitable drain location.
3. Run an unobstructed drain line from the sump overflow to the drain as shown below.
4. Install Sump Drain Solenoid Valve (C) in the drain line from the sump as indicated below. From the outlet on
this drain valve, run a line to a suitable drain location.
Note: Water Supply Solenoid Valve
(A) is not the same as the
Drain Solenoid valves (B) and
(C). Make sure to use the
Side of HRE Unit
proper valve for each location.
Check your local code
Sump Drain Pipe
requirements for proper
installation of this type of
system. Additional drain and
supply plumbing may be
needed to meet your local
code.
Evaporative
Cooling
Media
Sump Overflow Pipe
Sump
Caution: All solenoid valves A, B,
and C must be installed below the
roof to protect the supply water line
from freezing. If these valves cannot
be installed below the roof, an
Roof Curb
Roof Line
Sump Drain
Solenoid
Valve (C)
alternate method must be used to
protect these lines from freezing.
Water Supply
Solenoid Valve (A)
Drain
Solenoid
Valve (B)
Supply Line
Trap
Drain
Line
8
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TROUBLE SHOOTING FOR EVAPORATIVE MODULE
Symptom
Solution
Insufficient water
A. Check water level in base pan. The level should be at 2 inches.
B. Check the pump filter at the inlet. Clean the filter if clogged or dirty.
C. If pump is not operating, check wiring for loose connections and proper
voltage.
volume or recirculation
pump not operating
Irregular water
distribution on cooling
media
Water distribution header, orifices or media partially blocked or plugged.
Remove evaporative cooler from unit.
Disassemble and clean distribution header, orifices and media.
A. Check water flow across the face of the media. Irregular water distribution
must be corrected (see above)
Scale and mineral
deposit formation on
face of media
B. Increase water flow rate. Media is self cleaning with flow rate of 11⁄2 to 2
gpm per square foot of media top area. Generally this flow rate prevents
dissolved solvents from collecting on the media. To prevent further trouble,
flush and clean the system more frequently.
C. If this condition persists, chemicals may need to be added. Water pH
should be maintained between 6 and 8.
A. Irregular water distribution on face of media (see above).
B. Average face velocity exceeds 650 fpm. Decrease fan rpm and airflow.
C. Localized face velocities exceeding 650 fpm. Air filters or media face area
is partially blocked. Clean or replace air filters and media.
D. Check the overflow for blockage.
Water Carry-Over
A. Irregular water distribution over face of media (see above).
B. Check for uniform air flow.
Inadequate cooling
C. Check outside wet-bulb temperature. High wet-bulb temperatures can
decrease performance.
D. Check water flow rate over media. Flow rate should be 11⁄2 to 2 gpm per
square foot of media top area.
A. Check the water bleed off rate and make sure that it is not excessive.
B. Check water level in base pan. The level should be at 2 inches.
Excessive water
discharge into drain
Pad installed backwards. To get the
performance from the cooling pads,
they must be installed properly. The
pads are manufactured with 15/45
degree flute angles. The pads must
always be installed with the steeper
flute angle sloping down toward the
entering air side. See figure on right.
Poor performance after
cooling pad
replacement
45°
Entering Air
Leaving Air
15°
9
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EVAPORATIVE COOLING MAINTENANCE
Regularly scheduled maintenance is the key to peak
performance, minimized cost, and extended life of the
evaporative cooler. The following is a checklist of
Continuous operation in this manner may cause
serious damage and void the warranty.
items that need to be looked at on a regular basis.
7. At the end of each cooling season the
evaporative cooler should be thoroughly cleaned.
A dispersant and biocide (consult water
1. The media should be checked for mineral and
foreign material deposits that have built up. If
these items are left on the media, the life and
performance of the unit will be greatly reduced.
Also, there are risks of water carry over when this
type of condition exists. When signs of mineral
build-up are noticed, you should increase the
bleed off rate. If this does not solve the problem,
chemicals may need to be added to the water.
The evaporative pads tend to be self cleaning.
Depending on water quality and system
treatment consultant for suitable materials and
dosage levels) should be recirculated for 12 to 24
hours prior to performing the following steps:
a) Disconnect power to unit.
b) Shut off all water to the unit
c) Open evaporative cooling section door
d) Flush distribution headers and media for 20
minutes
e) Turn off pumps and drain all water distribution
piping, headers, etc.
maintenance, the useful life of the pads should
be 3 to 5 years.
f) Dry media completely by running blowers.
g) Brush media as described in Paragraph 2 and
perform steps d and e again.
h) Clean all remaining components (i.e. sump,
pump, etc.) of any mineral deposits or foreign
materials
2. The media should be periodically brushed lightly
with a soft bristle brush in an up and down
motion (never brush side-to-side) while flushing
with water. This will also aid in reducing the
amount of foreign material build-up.
i) Replace all worn or non-functioning parts
j) Reassemble the cooling unit.
k) Close cooling section door.
3. The water should be shut off and all the lines
drained when the temperature drops below 50°F.
l) Turn the main disconnect 'ON', leaving the
cooling switch in the 'OFF' position.
4. When the evaporative cooler is going to be used
for the first time each season, it is recommended
that the media be flushed with clean water for a
period of 2 minutes (see Evap Module Start-Up
on page 7).
8. If the evaporative cooler will be turned off during
the cooling season for an extended period of
time, it is recommended that the media be dried
out. This can be accomplished by allowing the
blowers to continue to run for 1-2 hours. Doing
so, will prevent organic build-up on the media
and subsequent odors getting into the space.
5. At the beginning of each cooling season, the
upright recirculating pump should have the shaft
oiled and spun to eliminate the potential of
seizing and pump burn out.
9. Media should be permitted to dry once per week
by allowing the blowers to run for 1-2 hours.
6. If the cooling media was removed from the unit,
check to make sure that is not installed
backwards. If the media is installed backwards,
there will be large amounts of water carry over
downstream of the evaporative cooler.
10. A flush cycle should be performed weekly for one
hour with the fans off.
10
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WATER COIL APPLICATION
RECOMMENDATIONS
Factory installed heating components are
mounted down stream of the energy wheel (and
direct evaporative cooler if supplied) on the
supply air side of the unit.
See FIGURE 10 for coil connection location. 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 air stream coil connections.
Water coil
connections
FIGURE 10
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.
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.
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.
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.
3. The air vent at the uppermost point should be
temporarily opened during system start-up to
11
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ELECTRIC HEATER APPLICATION/OPERATION
Factory installed electric heaters can be provided for preheat and/or post-heat (see FIGURE 11). 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 outdoor air temperature falls below the
set point, 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 4-stage, step control. Post-heaters are not single point wired
(see ELECTRICAL CONNECTIONS, page 5). The functionality of a 4-stage heater is the same
as the 2-stage preheater above, except it has an additional two stages of heat control.
Post-heaters supplied with Greenheck temperature control package are 3-stage with binary
control that provides 7 steps of heating. For example, a 35 kW heater with three stages will be
composed of 5, 10, and 20 kW stages. The stages essentially ‘mix and match’ to provide heat
output from 5 kW to 35 kW, in 5 kW increments.
FIGURE 11
Disconnect
Post-Heater Control Panel
The post-heater is not single point
wired to the HRE control center.
Separate power must be supplied
to the post-heater disconnect.
Access to the post-heater control
panel is through the exhaust filter
door. The top portion of the indirect
evaporative cooling media must be
removed from the unit along with
the exhaust filters.
Electric Preheater
The preheater is single point
wired to the HRE control
center. Access to the
Electric Post-Heater
preheater control panel is
through the supply filter door.
12
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FROST CONTROL APPLICATION/OPERATION
When outdoor air temperatures are extremely cold, moisture condensation and frosting on the energy recovery
wheel is possible. Frost control is an optional feature that will prevent wheel frosting. Two options are available:
1) Timed Exhaust frost control and
2) Preheat frost control
Timed exhaust frost control includes a thermostat (with
Indoor RH @ 70°F
Frost Threshold Temp
probe) mounted in the supply air inlet compartment (see
FIGURE 13, page 14) and a timer (Figure 12) mounted in the
HRE control center. The thermostat will turn on the timed
exhaust frost control feature at a predetermined field
adjustable outdoor air temperature (referred to as the Frost
Threshold temperature). The typical temperature setting
20%
25%
30%
2°F
7°F
14°F
TABLE 1
corresponds to the indoor air relative humidity as shown in TABLE 1.
Testing (refer to FIGURE 12)
• 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.
• Turn the temperature sensor up as high as possible.
The supply blower should cycle on for one minute,
then turn off for one minute.
A1
B1
15
0.8 0.6
1.0 0.4
0.2
Dip
Switch
0
• After testing, set the Timer Scale as follows: T1 = 10
minutes, T2 = 1 hour
T2
1 MIN T2
• 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.
Timer
Scale
1 MIN T1
0.8 0.6
1.0 0.4
0.2
0
Preheat frost control (see FIGURE 11, page 12) includes a
thermostat (with probe) and an electric heater located in the
supply air inlet compartment and an air pressure switch in the
supply air outlet compartment. The thermostat should be set
according to the Frost Threshold temperatures shown in TABLE 1.
When the outdoor air temperature reaches the thermostat setting,
the electric preheater will turn on and warm the air entering the energy
wheel.
T1
16
18
A2
FIGURE 12
Testing
• Turn the thermostat as high as it will go. The heater should turn on.
• If it doesn’t, either put the supply side doors on or temporarily jumper the
air pressure switch to avoid nuisance tripping of the pressure switch.
Remember to remove the jumper.
DIRTY FILTER SWITCH SETUP
This unit may be equipped with a dirty filter switch that functions on differential air pressures to close a relay
when the unit filters are clogged and need cleaning. This 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 electrical control center.
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 inlet compartment). Remove the switch cover plate. 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 (refer to electrical diagram). If there is no power, turn the adjustment screw on the dirty filter gage
clockwise until you have power. 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.
13
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ECONOMIZER APPLICATION/OPERATION
The energy recovery wheel may be de-energized for the purpose of providing economizer (free cooling)
operation. This can be achieved with a signal from a Temperature or Enthalpy sensor mounted in the supply air
inlet compartment (see FIGURE 13). This Primary sensor will de-energize the energy wheel when the outdoor air
temperature (factory default is 65°F) or enthalpy (factory default is the ‘D’ setting) is below the field adjustable
set point. An additional Override temperature sensor is also furnished in the supply air inlet compartment to
deactivate economizer mode (see FIGURE 13). The Override (with field adjustable set point) is set at some
temperature lower than the Primary sensor (factory default is 50°F). 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 (terminals referenced below are in the unit control center — see FIGURE 5, Item #7)
Temperature sensor with Override
• Turn both Temperature and Override
thermostats down as low as they go.
The wheel should be rotating.
FIGURE 13
• 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.
• Turn both sensors as high as they will
Enthalpy Sensor
(Primary Sensor)
go. The wheel should start rotating.
• Set the Temperature sensor to the
desired temperature for economizer
Timed Exhaust
Override
Frost Control
operation to begin. Set the Override
sensor to the desired temperature for
economizer operation to end (factory
default is 65°F and 50°F, respectively).
Probes
Enthalpy sensor with Override
• A factory-installed 620 ohm resistor is
connected across terminals SR and +.
The Override sensor should be turned
down below current temperature in unit. Turn the unit on; LED on the sensor should be off. Check
continuity across 2 and 3, there should not be continuity. There should be continuity between
terminals 1 and 2.
• Disconnect the 620 ohm resistor from terminals SR and +. LED should turn on. There should be
continuity between terminals 2 and 3. There should not be continuity between terminals 1 and 2.
• Turn the Override sensor above current temperature in unit. There should be continuity between
terminals 3 and 6. Set the Override sensor to the desired temperature for economizer operation to end
(factory default is 50°F).
• Reconnect the factory-installed jumper.
AUTO DRY CYCLE
The HRE may be supplied with a timer to delay turning off the unit to allow the evaporative cooler media pads
to dry. The blowers continue to run for a user designated time (factory default is 1.5 hours) following a signal to
turn the HRE unit off. The timer is located in the unit control center and can be adjusted from 15 minutes to 3
hours. This option is designed to prevent bacteria/mold growth on the pads. Refer to diagram in unit control
center for wiring.
14
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START UP CHECKS
**WARNING**
DO NOT OPERATE ENERGY RECOVERY VENTILATOR WITHOUT THE FILTERS AND BIRDSCREENS INSTALLED.
THEY PREVENT THE ENTRY OF FOREIGN OBJECTS SUCH AS LEAVES, BIRDS, ETC.
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.
CAUTION: See **WARNING** on page 1 and above
For proper unit function and safety, follow everything in this start-up procedure in the order presented. This to
be done after the electrical and gas connections are complete.
Pre-Start Check List
1. Disconnect and lock-out all power switches to fan.
2. Check all fasteners, set screws and locking collars on the fan, bearings, drive, motor base and
accessories for tightness.
3. Rotate the fan wheel by hand and assure no parts are rubbing.
4. Check the V-belt drive for proper alignment and tension.
Special Tools Required
• Voltage meter
• Incline manometer or equivalent
• Tachometer
• Thermometer
• Amperage meter
GENERAL
Check all fasteners and set screws for tightness. This is especially important
for bearings and fan wheels. Also, if dampers are not motorized, check that
they open and close without binding.
n
o
i
t
Airflow
a
t
o
R
FAN WHEEL ROTATION
Hand rotate the blower to ensure that the wheel is not rubbing against the
scroll. If the blower is rotating in the wrong direction, the unit will move some
air but not perform properly.
FIGURE 14
To check the rotation, open the blower access panels, which are labeled either
supply or exhaust, and run the blower momentarily to determine the rotation.
Rotation should be in the same direction as airflow at the outlet (See FIGURES
14 & 15). Check for unusual noise, vibration or overheating of bearings. Refer to
the “Trouble Shooting” section of this manual if a problem develops.
To reverse the rotation, turn the power off and use the following procedure:
• For single phase units, rewire the motor per the instructions on the
motor.
FIGURE 15
• For three phase units, interchange any two power leads. (this can be
done at the motor starter).
15
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Check pulleys and belts for proper alignment to avoid unnecessary
belt wear, noise, vibration and power loss. Motor and drive shafts
must be parallel and pulleys in line (see FIGURE 16).
FAN RPM
The adjustable motor pulley is preset at the factory to the
customer specified RPM. Fan speed can be increased or
decreased by adjusting the pitch diameter of the motor pulley.
Multi-groove variable pitch pulleys must be adjusted an equal
number of turns open or closed. Any increase in fan speed
represents a substantial increase in load on the motor. Always
check the motor amperage reading and compare it to the
amperage rating shown on the motor nameplate when changing
fan RPM. Access these components through the labeled access
panels.
WRONG
WRONG
All access doors must be installed except the control center door.
To measure the fan rpm, the blower door will need to be removed.
Minimize measurement time because the motor may overamp with
the door removed. Do not operate units with access doors/panels
open or without proper ductwork in place as the motors will
overload.
WRONG
CORRECT
FIGURE 16
ENERGY RECOVERY WHEEL
CAUTION: See **WARNING** on page 1 and 15
For the HRE-20 and HRE-45, open the access door marked
"Energy Wheel Cassette Access". UNPLUG the wheel drive
motor and remove the metal spacer. Then pull the cassette
out halfway as seen in FIGURE 17.
Note: For the HRE-55 and HRE-90, the energy recovery
wheel does not slide out due to its size and weight. There is
ample room inside the unit to perform energy recovery wheel
servicing.
Turn the energy recovery wheel by hand to verify free
operation. Check that the air seals, located around the
outside of the wheel and across the center (both sides of
wheel), are secure and in good condition. Replace cassette
into unit, plug in wheel drive, replace access door and apply
power. Observe that the standard and high flow wheel
rotates freely at about 60 RPM.
FIGURE 17
If wheel does not rotate or rotates too slowly, remove the
cassette (following the instruction on page 20). Air seals, which are too tight, will prevent proper rotation of the
energy recovery wheel. Recheck the air seals for tightness. Air seal clearance may be checked by placing a
sheet of paper, to act as a feeler gauge, against the wheel face. To adjust the air seals, loosen all eight seal
retaining screws. These screws are located on the bearing support that spans the length of the cassette
through the wheel center. Tighten the screws so the air seals tug slightly on the sheet of paper.
COILS
Leak test thermal system to insure tight connections.
16
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ROUTINE MAINTENANCE
CAUTION: See **WARNING** on Page 1 and 15
Once the unit has been put into operation, a periodic maintenance program should be set up to preserve the
reliability and performance. Items to be included in this program are:
• BELTS
• MOTORS
• WHEEL AND FASTENERS
• VIBRATION
• FILTER MAINTENANCE
• COIL MAINTENANCE
• ENERGY WHEEL CASSETTE
FAN BELTS
Belt Span
Belts tend to stretch after a period of time. They should be
periodically checked for tension and wear. When replacing
belts, use the same type as supplied with the unit.
Replacement of belts should be accomplished by loosening
the motor slide plate so the belts may be removed by hand.
Do not force belts on or off as this may cause breakage of
cords and lead to premature belt failure.
Belt tension should be adjusted to allow 1/64 in. of belt
deflection per 1 in. of belt span. For example, a 16 in. belt
span should have 16/64 in. or 1/4 in. of deflection with
moderate thumb pressure at mid-point between the pulleys
(FIGURE 18).
Belt Span
Deflection =
64
FIGURE 18
MOTORS
Motor maintenance is generally limited to cleaning and lubrication (where applicable). Cleaning should be
limited to exterior surfaces only. Removing dust and grease build-up on the motor housing assures proper
motor cooling. Use caution and do not allow water or solvents to enter the motor or bearings. Under no
circumstances should motors or bearings be sprayed with steam, water or solvents.
Greasing of motors is intended only when fittings are provided. Many fractional horsepower motors are
permanently lubricated for life and require no further lubrication. Motors supplied with grease fittings should
be greased in accordance with the manufacturer’s recommendations.
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.
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.
17
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VIBRATION
Excessive vibration maybe experienced during initial start-up. Left unchecked, excessive vibration can cause a
multitude of problems, including structural and/or component failure. The most common sources of vibration
are listed below.
Many of these conditions can be discovered by careful observation.
1. Wheel Unbalance
Refer to the troubleshooting section of this manual for corrective actions.
2. Drive Pulley Misalignment
If observation cannot locate the source of vibration, a qualified
technician using vibration analysis equipment should be consulted. If the
problem is wheel unbalance, in-place balancing can be done providing
there is access to the fan wheel.
3. Incorrect Belt Tension
4. Bearing Misalignment
5. Mechanical Looseness
6. Faulty Belts
7. Drive Component Unbalance
8. Poor Inlet/Outlet Conditions
9. Foundation Stiffness
Generally, fan vibration and noise are transmitted to other parts of the
building by the ductwork. To eliminate this undesirable effect, the use of
heavy canvas connectors is recommended.
EXTERNAL FILTER MAINTENANCE
Aluminum mesh 2 in. 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.
FIGURE 19
To remove these filters, remove bottom bolt in the
access door on the side of the weatherhood. Slide
the access door up and then pull out. Then, slide
the filters out (see FIGURE 19).
Clean filters by rinsing with a mild detergent in
warm water. After the filters are dry, an adhesive
spray available at most filter distributors may be
applied to increase filter efficiency.
TABLE 2
Internal
Quantity
Filter Size
Model
INTERNAL FILTER MAINTENANCE
Opening the access doors labeled as “Filter
Access” provides access to the pleated 30%
filters (if the filter option was purchased). These
filters should be checked regularly, cleaned or
replaced as needed. See TABLE 2 for pleated filter
size and quantity for each unit.
HRE-20
HRE-45
HRE-55
HRE-90
20 x 20
20 x 25
16 x 25
20 x 20
2
3
6
8
18
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WATER COIL MAINTENANCE
CAUTION: See **WARNING** on Page 1 and 15
FILTERS
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. See page 18 for more information
on filter maintenance.
COIL MAINTENANCE
1. Coils must be clean 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.
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 fins, while cleaning.
CAUTION: Fin edges are sharp.
**WARNING**
BIOLOGICAL HAZARD. MAY CAUSE DISEASE. CLEANING SHOULD BE PERFORMED BY QUALIFIED PERSONNEL.
19
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ROUTINE ENERGY RECOVERY WHEEL MAINTENANCE
CAUTION: See **WARNING** on Page 1 and 15
MAINTENANCE OF THE ENERGY RECOVERY WHEEL
Annual inspection of the energy recovery wheel is recommended. Units ventilating smoking lounges and other
non-clean air spaces should have energy recovery wheel inspections more often based upon need. Inspections
for smoke ventilation applications are recommended bimonthly to quarterly until a regular schedule can be
established.
ACCESSING ENERGY RECOVERY WHEEL
For the HRE-20 and HRE-45, open the access door marked "Energy Wheel Cassette Access" (FIGURE 20).
UNPLUG the wheel drive motor and remove the metal spacer. Then pull the cassette out halfway (FIGURE 21).
The energy recovery wheel cassettes for model HRE-55 and HRE-90 do not slide out due to their size and
weight. Service to these energy wheel cassettes can be done through the Filter and Electrical Control Box
access doors, or by entering the unit through the Exhaust Blower access door.
**WARNING: Disconnect power to the unit before performing any type of service.**
FIGURE 20
FIGURE 21
20
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REMOVING THE ENERGY RECOVERY WHEEL SEGMENTS
Model HRE-20, 45, 55, & 90
Bracket Segment Retainer
Steel retainers are located on the
inside of the wheel rim (FIGURE 22).
Push the retainer toward center of
wheel, then lift up and away to
Lift Away
From Segment
release segments (FIGURE 23).
Catch-
Segment Retainer
Inside of Wheel Rim
Spoke
Push Toward Center
FIGURE 22
IMPORTANT! PLACE RETAINERS BACK IN THE ORIGINAL
POSITION BEFORE ROTATING THE ENERGY
RECOVERY WHEEL. OTHERWISE DAMAGE TO
RETAINER WILL OCCUR.
FIGURE 23
CLEANING ENERGY RECOVERY WHEEL SEGMENTS
If the wheel appears excessively dirty, it should be cleaned to ensure maximum operating efficiency. Only
excessive buildup of foreign material needs to be removed. DISCOLORATION AND STAINING OF ENERGY
RECOVERY WHEEL DOES NOT AFFECT ITS PERFORMANCE.
™
Thoroughly spray wheel matrix with household cleaner such as Fantastic or equivalent. Gently rinse with warm
water and using a soft brush remove any heavier accumulation. A detergent/water solution can also be used.
Avoid aggressive organic solvents, such as acetone. The energy recovery wheel segments can be soaked in the
above solution overnight for stubborn dirt or accumulation.
After cleaning is complete, shake the excess water from the wheel or segments. Dry wheel or segments before
placing them back into the cassette. Place wheel or segments back into cassette by reversing removal
procedures.
** DO NOT CLEAN ENERGY RECOVERY WHEEL SEGMENTS WITH WATER IN EXCESS OF 140°F
** DO NOT DRY ENERGY RECOVERY WHEEL SEGMENTS IN AIR IN EXCESS OF 140°F.
21
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PARTS LIST
7
11
8
3
6
1
5
2
9
12
7
4
10
Model HRE
(shown with indirect evaporative cooler,
optional direct evaporative cooler, and
indirect gas heater)
1. Supply blower
8. Electrical control box (standard features)
- Single point power
- Forward curved fan
- Adjustable motor mount for belt tensioning
- Adjustable sheaves for speed control
- Disconnect interlocked with access door
- Motor starters for the supply blower, exhaust
blower and energy wheel motors.
2. Vibrations isolators (quantity 4 per blower)
- Neoprene
- 24 Vac, control circuit with terminal strip
9. Supply air tempering options
- Electric heat
3. Energy recovery wheel cassette
- Hot water heat
4. Removable energy recovery wheel segments
- Indirect gas heat
5. Optional supply weatherhood with 2 in. aluminum
mesh filter
10. Exhaust blower
- Forward curved fan
- Adjustable motor mount for belt tensioning
- Adjustable sheaves for speed control
6. Optional exhaust weatherhood with birdscreen
7. Optional supply and exhaust air filter racks for 2
in. pleated, 30% efficient filters
11. Indirect evaporative cooler
12. Direct evaporative cooler
22
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Trouble Shooting
Symptom
Possible Cause
Corrective Action
Blown fuse or open circuit
breaker.
Replace fuse or reset circuit breaker and check amps.
Defective motor or capacitor.
Motor starter overloaded.
Electrical.
Replace
Blower Fails to
Operate
Reset starter and check amps.
Check for On/Off switches. Check for correct supply voltage.
Check for broken or loose belts. Tighten loose pulleys.
Drive.
Control power (24 Vac) wiring
run is too long (resistance
Shorten wiring run to mechanical room or install a relay
which will turn unit on/off (C/F for relay information).
should not exceed 0.75 ohms).
Motor Starters
“Chatter” or Do
Not Pull In
Incoming supply power is
less than anticipated. Voltage
supplied to starter coil must
be within +10% / -15% of
nominal voltage stated on
the coil.
Need to increase supply power or use a special control
transformer which is sized for the actual supply power.
Cfm too high.
Check cfm and adjust drives if needed.
Static pressures are higher or
lower than design.
If higher, ductwork should be improved.
If lower, fan rpm should be lower.
Blower rotation is incorrect.
Motor voltage incorrect.
Motor horsepower too low.
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.
Shorted windings in motor.
Unit damper not fully open.
Replace motor.
Adjust damper linkage or replace damper motor.
System static pressure too high Improve ductwork to eliminate losses using good duct
practices.
Blower speed too low.
Check for correct drives and rpm with catalog data.
For 3-phase see Fan Wheel Rotation on page 15.
Fan wheels are operating
backwards.
Low Airflow (cfm)
Dirty filter or energy wheel.
Leaks in ductwork.
Follow cleaning procedures on pages 18 and 21.
Repair.
Elbows or other obstructions
may be obstructing fan outlet.
Correct or improve ductwork.
Belt slippage.
Adjust belt tension.
Blower fan speed too high.
Filter(s) not in place.
Check for correct fan rpm. Decrease fan speed if necessary.
Install filters.
High Airflow (cfm)
Insufficient static pressure (Ps)
(airflow resistance).
Induce Ps into system ductwork. Make sure grilles and
access doors are installed. Decrease fan speed if necessary.
* Always provide the unit model and serial number when requesting parts or service information. * Always check motor amps and compare to nameplate rating.
23
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Trouble Shooting
Symptom
Possible Cause
Corrective Action
One or Both
Blowers Turn Off
Intermittently and
Back on After
Blower fan motor overloads are Decrease fan speed.
tripping and auto-resetting.
Exhaust Only frost control
sensors are tripping.
Adjust frost temperature sensor set point as needed.
About 2 Minutes
Air seals are too tight.
See Energy Recovery Wheel on page 16.
“Economizer” sensors are
operating.
Adjust temperature or enthalpy set points as needed.
Energy Wheel
Does NOT Turn
No power to wheel motor.
Make sure wheel drive is plugged in. Verify power is
available.
Wheel drive belt
Check for loose or broken belts. Replace belts (consult
factory).
Wheel motor overloads are
tripping, due to rubbing
between wheel and air seals.
Recheck air seals, make sure they are not too tight. See
Energy Recovery Wheel on page 16.
Energy Wheel
Runs Intermittently
Fan wheel rubbing on inlet
Adjust wheel and/or inlet cone. Tighten wheel hub or bearing
collars on shaft.
Bearings.
Replace defective bearings (s). Lubricate bearings. Tighten
collars and fasteners.
Wheel out of balance.
Replace or rebalance.
Loose wheel on shaft.
Tighten wheel setscrew.
Tighten sheave setscrew.
Loose motor or blower sheave.
Belts too loose.
Belts too tight.
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.
Worn belt.
Replace.
Motor base or blower loose.
Build up of material on wheel.
Bearing and drive misaligned.
Tighten mounting bolts.
Clean wheel and housing.
Realign.
Noise being transmitted by
duct.
Make sure duct work is supported properly. Make sure duct
work metal thickness is sized for proper stiffness. Check duct
size at discharge to ensure that air velocities are not too high.
* Always provide the unit model and serial number when requesting parts or service information. * Always check motor amps and compare to nameplate rating.
Warranty
Greenheck warrants this equipment to be free from defects in material and workmanship for a period of one year from
the purchase date. The energy recovery wheel is warranted to be free from defects in material and workmanship for a
period of five years from the purchase 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.
Due to continuing product development Greenheck has the right to change specifications without notice
GREENHECK
P.O. BOX 410 SCHOFIELD, WISCONSIN 54476-0410
IOM HRE FS
Rev. 2, July 2002
PH. 715-359-6171
®
Copyright © 2002 Greenheck Fan Corp.
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