Trane Package Unit: 4WCX
Re: Indoor Blower Not Running
The 4WCX package unit uses a standard, PSC motor. The motor is controlled by a Fan-Delay Relay (FDR).
Qty |
Possible Causes: |
1 |
Bad Fan-Delay Relay (FDR) |
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Bad Blower Motor |
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Bad Capacitor |
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No Call for "G" |
CHECKOUT:
1. Check High Voltage Power
- Check for 230VAC inlet power across L1 and L2 of the compressor contactor.
- No Power --> Check Disconnect and Breakers
- Check for a "Short-to-Ground" before checking breaker!
2. Check Low Voltage Power
- Ensure the thermostat is calling for either heating or cooling.
- At the low voltage wiring, check for 24VAC between "Red" and "Blue".
- No Power = Bad Transformer or Blown Fuse
- Check for 24VAC between "Green" and "Blue".
- No Power = No Call for Fan --> Recheck Stat
3. Check Fan Relay
- Low Voltage
- At the FDR, check for 24VAC between the "Red" wire on terminal "A" and the "Blue" wire on terminal "B".
- No Power on "A" = No 24V Power --> Check Fuse & Transformer.
- At the FDR, check for 24VAC between the "Green" wire on terminal "T" and the "Blue" wire on terminal "B".
- Power on "G" + No Power at "T" = Bad Wiring
- Inlet Line Power
- At the FDR, check for 230VAC between the "Red" wire on terminal 1 and the "Black" wire on the Contactor inlet power.
- Outlet Line Power
- At the FDR, check for 230VAC between the "Red" wire on terminal 3 and the "Black" wire on the Contactor inlet power.
- Low Voltage Present + No Outlet Power = Bad FDR
4. Check Capacitor
- Disconnect power to the unit and test the blower motor capacitor.
- Less that 80% rated capacity = Bad Capacitor
- Good Capacitor + Power to Motor + No Operation = Bad Blower Motor