Nordic R-09, Installation And Service Manual, Page: 37 / 60

11-May-2021 Page 37 002512MAN-01
FAN/BLOWER TROUBLESHOOTING
Fault Possible Cause Verification Recommended Action
Low Airflow
Dirty air filter Inspect. Replace.
Dirty air coil Inspect. Clean.
Poor Ductwork Measure delta T between supply
and return ducts at the unit, it in
heating mode, it should not be
above 30°F(17°C).
The ECM can provide only a cer-
tain amount of torque, according
to the speed SP1/SP2/SP3/SP4
selected. The ductwork is poorly
designed or greatly undersized if
the fan motor cannot provide the
required airflow.
Airflow selected on 4-
speed terminal strip
(SP1/SP2/SP3/SP4) is too
low
Check selection. Select a higher setting.
Fan operating on
wrong speed, or
does not respond
to speed selec-
tion change
Fan Control Signal Har-
ness is loose
Verify that the connector is properly
inserted into the fan motor. Gently
tug on each wire to verify it is
properly inserted into the connector.
Repair any loose connections.
Faulty Control Signal Har-
ness or faulty motor head
Ensure signal is present
on terminal strip
Measure 24VAC between White/
Black (pin C) and the following at the
fan control signal harness (insert
probes in connector where wire is
inserted, do not unplug the connect-
or):
Recirculation = red (pin 1)
SP1 = orange (pin 2)
SP2 = blue (pin 3)
SP3 = brown (pin 4)
SP4 = grey (pin 5)
If proper signal isn’t present, re-
place Fan Control Signal Har-
ness. If proper signal is present,
replace fan motor head.
Fan not operat-
ing or operating
intermittently
Fan Control Signal Har-
ness and/or Fan Power
Harness is loose
Verify that the connector is properly
inserted into the fan motor. Gently
tug on each wire to verify it is
properly inserted into the connector.
Repair any loose connections.
Faulty Control Signal Har-
ness or faulty motor head
Ensure signal is present
on terminal strip
Measure 24VAC between White/
Black (pin C) and the following at the
fan control signal harness (insert
probes in connector where wire is
inserted, do not unplug the connect-
or):
Recirculation = red (pin 1)
SP1 = orange (pin 2)
SP2 = blue (pin 3)
SP3 = brown (pin 4)
SP4 = grey (pin 5)
If proper signal isn’t present, re-
place Fan Control Signal Har-
ness. If proper signal is present,
replace fan motor head.
Faulty Fan Power Har-
ness or faulty motor
Insert the tips of the voltmeter
probes into the back of the connect-
or at the fan to measure the voltage
across the red and black wires.
Value should be 230VAC.
Replace Power Harness if
230VAC is not present, replace
motor if 230VAC is present