York Package Unit: PCG4

Re: Flashing Code 5

Code 5 = Limit Switch Circuit Open for More Than 15 Minutes

► The automatic-reset primary Limit Switch and the manual-reset Roll-Out Switch are wired in series, so either limit open will initially generate a Code 4.

► If the limit circuit remains open for more than 5 minutes, the control will switch to a Code 11. 

► If the limit circuit remains open for more than 15 minutes, the control assumes that a Roll-Out Switch has tripped and will switch to a Code 5. 

CHECKOUT:

1. Check the Limit Circuit

• At the control board 9-pin plug, use a volt meter to check for 24VAC on each side of the limit circuit.
  • Check voltage between Pin#1 (Red/Grn 36) and "C".
  • Check voltage between Pin#5 (Red/Blk 35) and "C".
    • Power on One Side Only = Limit Circuit Open → Step 2. Check Limits
    • Power on Both Sides = Limit Circuit Closed ⇒ Reset the board by cycling power to the unit. 
      • Code 4 Returns + Limit Circuit Closed = Bad Control Board

2. Check Limits

• Check the Roll-Out Limit
  • The Roll-Out Limit is located on the plate above the burners.
  • With the wires attached to the limit switch, check for 24VAC from each side of the Roll-Out Limit to "C".
    • Power on Both Sides = Roll-Out Limit Closed ⇒ Check the Primary Limit (below)
    • Power on One Side Only = Roll-Out Limit Open ⇒ Attempt to reset the limit by pressing down on the button between the wire terminals on the limit switch.
      • After pressing the reset, recheck for 24VAC from each side of the Roll-Out Limit to "C".
        • Power Still on One Side Only = Bad Roll-Out Limit 
        • Power on Both Sides ⇒ Reset the control board by cycling power to the unit, then → Step 4. Check Burners
• Check the Primary Limit
  • The Primary Limit is located inside the blower compartment and protrudes into the heat exchanger compartment.
  • With the wires attached to the limit switch, check for 24VAC from each side of the Limit Switch to "C".
    • Power on One Side Only = Limit Switch Open
      • Limit Switch Open + Hot Heat Chamber → Step 3. Check Blower
      • Limit Switch Open + Cool Heat Chamber = Bad Limit Switch
    • Power on Both Sides = Limit Switch Closed ⇒ Reset the board by cycling power to the unit. 
      • Code 4 Returns + Limit Circuit Closed = Bad Control Board

3. Check Blower

• During a Code 4 or 5 lockout, the indoor blower should be running continuously.
  • No Blower Operation ⇒ Continue
• Make sure that both the High Voltage and Low Voltage plug are secure at the ECM blower motor.
• Check for 24VAC at the control board between "W SPD" and "24V COM".
  • ​​​​​​​Power Present + No Blower = Bad Blower Motor
  • No Power Present = Bad Control Board

4. Check Burners

• Initiate a call for Heat.
• Observe the burners during operation.
• Before the blower starts, look for any roll-out or unusual burner patterns.
• When the blower starts, look for any change in the burners or flame roll-out.
  • ​​​​​​​Roll-out or bad burning before the blower starts = Clogged Heat Exchanger, Bad Inducer, or Combustion Air Problems
  • Roll-out or bad burning after the blower starts = Bad Heat Exchanger