Specifications

33
Table 13 — ERV Troubleshooting
SYMPTOM POSSIBLE CAUSES ACTION TO CHECK POSSIBLE REMEDY
ERV will not turn on
Disconnect switch is in the off
position
Verify that the disconnect switch
is in the 'ON' position
Move the disconnect lever to the 'ON'
position.
No power to the ERV
Check for power at the discon-
nect switch
Using a volt meter verify that the voltage
being supplied to the ERV matches the
ERV's operating voltage. If the ERV oper-
ates on three phase power check all three
legs.
One or more blown fuses
Check for power at the bottom of
the fuse block
Using a volt meter verify that the voltage on
the bottom side of the fuse block matches
the ERV's operating voltage. If the ERV
operates on three phase power check all
three legs.
Control board transformer circuit
breaker is tripped
Look at the small transformer
next to the control circuit board
to see if the black circuit pushed
out
Depress the circuit breaker back in.
ERV is running but
blowers will not turn
The fan speed / CFM level is set
too low
Use the user interface push but-
ton to view the 'Outside Air' and
'Exhaust Air' settings
Adjust the fan speed / CFM demand levels
by pressing the user interface push button
and turning the adjust knob.
One or more blown fuses
Check for power at the bottom of
the fuse block
Using a volt meter verify that the voltage on
the bottom side of the fuse block matches
the ERV's operating voltage. If the ERV
operates on three phase power check all
three legs.
Rooftop Economizer Option (if
equipped) has shut down the
ERV because the rooftop unit is
in 'Free Cooling' mode
Check for continuity across the
mercury switch on the econo-
mizer damper.
Using a continuity meter check for continu-
ity across the two wires that connect to the
mercury switch on the economizer damper.
If the contacts are open, the rooftop unit is
in 'Free Cooling'.
Smoke Detector Option (if
equipped) has shut down the
ERV because it is sensing
smoke in the exhaust airstream
on the ERV.
Check for wiring errors.
Using the wiring schematics verify that the
smoke detector is wired to the control board
properly.
Low Temperature Lockout
Option (if equipped)
Check to see if the outside tem-
perature is above –30 F
(–34.4 C). Check for wiring
errors
Use a thermometer to measure the outside
temperature. Use the wiring schematics to
verify that temperature probe on the intake
air side of the ERV is wired properly.
Only one of the two
blowers is turning
The fan speed / CFM level is set
too low
Use the user interface push but-
ton to view the 'Outside Air' and
'Exhaust Air' settings
Adjust the fan speed / CFM demand levels
by pressing the user interface push button
and turning the adjust knob.
Rooftop Economizer with Power
Relief Option (if equipped) has
shut down the supply blower
because the rooftop unit is in
'Free Cooling' mode
Check for continuity across the
mercury switch on the econo-
mizer damper
Using a continuity meter check for continu-
ity across the two wires that connect to the
mercury switch on the economizer damper.
If the contacts are open, the rooftop unit is
in 'Free Cooling'.
One of the blowers is wired
incorrectly
Check for wiring errors.
Using the wiring schematics verify that both
the power wires and the control wires are
connect properly.
The ERV Standard Frost Protec-
tion Option has turned off the
supply blower to defrost the
wheel
Check for frost on the wheel. Wait for Defrost mode to finish.
Blowers are on but
the wheel is not
turning
The ERV Enthalpy Control, Dry
bulb Control / Wheel Bypass
Stop / Jog Option (if equipped)
is activated
Check for Stop / Jog movement
of wheel.
Wait until sequence is completed.
The wheel motor is unplugged.
Check to see if the connector
between the wheel motor and
the cabinet wiring is securely
connected.
Plug the two connectors together.
The wheel motor is wired
incorrectly.
Check for wiring errors.
Compare the wheel motor, control board
and relay are wired correctly.
The wheel belt is off or broken Check the wheel belt.
Verify that the wheel belt is seated in the
pulley and on the rim of the wheel.
The air seals on the wheel are
too tight
Check to see if the wheel spins
freely.
Carefully rotate the wheel by grabbing the
outer rim and spinnig the wheel. After let-
ting go the wheel should continue to spin for
three to four seconds. Should the air seals
need adjusting see the maintainence sec-
tion of this book.