Maritime Geothermal TF-45, Installation And Service Manual

Page: 53 / 89

1-Jul-2017 Page 53 001223MAN-05
FAN/BLOWER TROUBLESHOOTING
Fault Possible Cause Verification Recommended Action
Low Airflow
Dirty air filter Inspect. Replace.
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 fan will provide proper
airflow up to 0.5 inH2o for 1/2HP
motors and 0.7 inH2o for 1HP
motors. The ductwork is poorly
designed or greatly undersized if
the fan motor cannot provide the
required airflow.
Airflow selected on tap
board is too low.
Check selection on tap board. Select a higher setting.
Air flow reduction is ena-
bled.
AR1 and AR2 are connected with a
dry contact or jumper.
Air flow reduction may not be fea-
sible with poor ductwork, and/or
lower Air Flow selections. In-
crease settings until unit operates
properly.
Fan operating on
wrong stage
speed (may be
hard to detect)
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 (pin
3) and the following at the fan con-
trol signal harness (insert probes in
connector where wire is inserted, do
not unplug the connector):
Recirculation = grey (pin 15)
Stage 1 = yellow (pin 6)
Stage 2 = yellow/black (pin14)
Stage 3 = violet (pin 2)
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 (pin
3) and the following at the fan con-
trol signal harness (insert probes in
connector where wire is inserted, do
not unplug the connector):
Recirculation = grey (pin 15)
Stage 1 = yellow (pin 6)
Stage 2 = yellow/black (pin14)
Stage 3 = violet (pin 2)
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
Dirty air coil. Inspect. Clean.