Troubleshooting Procedures For Direct Drive Plenum Fan - Trane WSC036E Installation, Operation And Maintenance Manual

Troubleshooting Procedures for Direct
Drive Plenum Fan
Prior to troubleshooting, verify all wiring and wiring
connections.The motor has internal protections that will
shut down the motor before damage occurs. A power
cycle is required to reset some of the internal protections.
Before proceeding, power down unit for 1 minute and then
power on.
Please follow steps sequentially unless directed differently
in solution.
Table 13. Troubleshooting for direct drive plenum fan
Step Symptom or Test
If obstruction is present, remove power from
Obstruction
unit and remove obstruction. Check fan wheel
1 blocking operation
for damage. Remove wheel/motor assembly
of evaporator fan.
if damaged.
Check line to line Voltage should be same as line to line voltage
2 voltage at pin 1, 2, input to unit. If voltage is same go to step 4.
and 3 of PPF-IDFP. If not, go to step 3.
Verify continuity
3 across fuse FU31, Replace fuse if continuity is not present.
FU32, and FU33.
Voltage should be greater than 1.0 VDC. If
Measure DC voltage voltage is greater the 1.0, go to step 8. If not,
4 across pin Vt and turn knob on MMC counter-clock wise 1 turn
com on MMC. and check voltage again. If no change in
voltage, go to step 5
Check for 24VAC If voltage is not present, verify thermostat
5 across pins A and B wiring. Go to step 4. If voltage is present, go
on F relay. to step 6.
Check for 10VDC
If voltage is not present, check wiring to F
across pin 9 on F
6 relay. Correct wiring if needed. Go to step 4.
relay an pin 8 of
If wiring is correct, replace relay.
PPM-IDFC.
Measure DC voltage
Voltage should be greater than 1.0 VDC. If
7 across pin Vt and
voltage not present, replace MMC.
com on MMC.
Verify VDC is same
across Vt and com
If voltage is not same, check for correct
8 on MMC and pin 1
wiring. If voltage is the same go to step 9.
and pin 8 on PPM-
IDFC.
Verify correct wiring
9 connections at KL3 If wiring is correct, replace motor.
in the motor.
RT-SVX23F-EN
Probable Cause and Solution
Troubleshooting
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