Trane Package Unit: 4YCC4
Re: Flashing Code 3
Code 3 = Pressure Switch Fault
A Code 3 will be generated in either of the following conditions:
- The pressure switch failed to close with the inducer motor energized.
- The pressure switch failed to re-open with the inducer motor de-energized.
Qty |
Possible Causes: |
|
Bad Pressure Switch |
3 |
Bad Inducer Motor |
|
Loose Pressure Switch Hose |
|
Clogged Pressure Port |
|
Bad Ignition Control Board |
CHECKOUT:
1. Check Controller
- Activate a call for heat from the thermostat (confirm 24VAC between "W" and "C")
2. Check Inducer Motor
- With "W' energized, check for 230VAC power between the IGN "Inducer Load" 21A (YL) and CC2 2C (BK).
3. Check Pressure Switch
- Ensure that the pressure switch hose is attached at the inducer pressure port and the pressure switch.
- Contacts
- With "W" energized:
- Check for 24VAC from each pressure switch terminal to Gnd.
- Power on Both Sides = Switch Closed
- Power on One Side Only = Switch Open
- Switch Open + No Power to Inducer = Bad Control Board
- Inducer Off + Switch Closed = Bad Pressure Switch (Stuck Closed)
- Remove one wire from the pressure switch and see if motor starts.
- Pressure
- With the inducer running, use a pressure gauge to check the inducer negative pressure.
- Pressure Above Switch Rating + Open Switch = Bad Pressure Switch
- Pressure Below Switch Rating = Clogged Pressure Port or Broken Inducer Fan Wheel (Bad Inducer Motor)
4. ADPS Switch Setting
- The ADPS switch will sometimes fail to re-open when set for the lowest setting.