Trane Package Unit: 4YCY
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 (stuck closed) with the inducer motor de-energized.
Qty |
Possible Causes: |
1 |
Bad Ignition Control Board |
1 |
Bad Inducer Motor |
|
Bad Pressure Switch |
|
Loose Pressure Switch Hose |
|
Clogged Pressure Port |
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 HI" 23A (BK) and CC1 1C (RD).
- Check for 230VAC power between the IGN "Inducer LO" 21A (BL) and CC1 1C (RD).
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 between both sides of the pressure switch and 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
- 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 Restricted Inducer Fan
4. ADPS Switch Setting
- The ADPS switch will sometimes fail to re-open when set for the lowest setting.