11NO PREVIOUS CODE – Stored codes are erased after 72 hours. On RED LED boards stored status codes can also be erased whenever power (115V or 24V) is interrupted. Run system through a low-heat, high-heat, or cooling cycle to check system.
12BLOWER ON AFTER POWER UP – (115V OR 24V) – Normal operation. Blower runs for the selected blower off- delay, if unit is powered up during a call for heat (R-W/W1 closed) or when (R- W/W1 opens) during the blower on-delay period.
13LIMIT CIRCUIT LOCKOUT – Lockout occurs if the limit, draft safeguard, flame rollout, or blocked vent switch* (if used) is open longer than 3 minutes. Control will auto-reset after 3 hours. See code 33.
14IGNITION LOCKOUT – System failed to ignite gas and prove flame in 4 attempts. Control will auto-reset after 3 hours. See status code 34.
21GAS HEATING LOCKOUT – Turn off power and wait 5 minutes to retry. Check for:
-Stuck closed gas valve relay on control.
-Miswire or short to gas valve wire.
22ABNORMAL FLAME-PROVING SIGNAL Flame is proved while gas valve is de- energized. Inducer will run until fault is cleared. Check for:
-Stuck open or leaky gas valve.
23PRESSURE SWITCH DID NOT OPEN Check for:
-Obstructed pressure tube.
-Pressure switch stuck closed.
24SECONDARY VOLTAGE FUSE IS OPEN Check for:
-Short circuit in secondary voltage (24V) wiring including thermostat leads. Disconnect thermostat leads to isolate short circuit.
31 HIGH-HEAT PRESSURE SWITCH OR |
RELAY DID NOT CLOSE OR |
REOPENED - Check for: |
- Control relay may be defective. |
32LOW-HEAT PRESSURE SWITCH DID NOT CLOSE OR REOPENED – If open longer than 5 minutes, inducer shuts off for 15 minutes before retry. If opens during blower on-delay period, blower will come on for the selected blower off- delay. Check for:
-Proper vent sizing.
-Low inducer voltage (115V).
-Low inlet gas pressure (if LGPS used).
-Inadequate combustion air supply.
-Disconnected or obstructed pressure tubing.
-Defective inducer motor.
-Defective pressure switch.
-Excessive wind.
-Restricted vent.
33LIMIT CIRCUIT FAULT – Indicates the limit, draft safeguard, flame rollout, or blocked vent shutoff switch* (if used) is open.Blower will run for 4 minutes or until open switch remakes whichever is longer. If open longer than 3 minutes, code changes to lockout #13. If open less than 3 min. status code #33 continues to flash until blower shuts off. Flame rollout switch and BVSS requires manual reset. Check for:
-Dirty filter or restricted duct system.
-Loose blower wheel.
-Defective switch or connections.
-Defective blower motor or capacitor.
-Inadequate combustion air supply (flame rollout switch open).
-Restricted vent.
-Proper vent sizing.
-Excessive wind.
34IGNITION PROVING FAILURE – If flame is not sensed during the trial for ignition period, the control will repeat the ignition sequence 3 more times before lockout #14 occurs. If flame signal is lost during the blower on-delay period, blower will come on for the selected blower off-delay. Check the following items first before proceeding to the next step.
-Gas valve turned off.
-Manual shut-off valve.
-Green/Yellow wire MUST be connected to furnace sheet metal.
-Flame sensor must not be grounded. To determine whether the problem is in the gas valve, igniter, or flame sensor the system can be operated in the component test mode to check the igniter. First remove the R thermostat connection from the control and initiate the component test sequence. Does the igniter glow orange/white by the end of the 15 second warm-up period?
43LOW-HEAT PRESSURE SWITCH OPEN WHILE HIGH-HEAT PRESSURE SWITCH IS CLOSED - Check for:
-Low-heat pressure switch stuck open.
-Disconnected or obstructed pressure tube.
-Miswired pressure switches.
-Low inlet gas pressure (if LGPS used).
Unplug igniter harness from control and initiate another component test sequence. Check for 115V between pin 1 and NEUTRAL-L2 on the control. Was 115V present for the 15 second period?
Reconnect the R thermostat lead and set thermostat to call for heat. Connect voltmeter across gas valve connections. Does gas valve receive 24V?
YES
Does gas valve open and allow gas to flow?
YES
Do the main burners ignite?
YES
Do the main burners stay on?
NO
Repeat call for heat and check flame sensor current during trial for ignition period. Is the DC microamps below 0.5?
YES
Clean flame sensor with fine steel wool and recheck current. Nominal current is 4.0 to 6.0 microamps.
Is current near typical value?
YES
Will main burners ignite and stay on?
YES
Fixed.
45 CONTROL CIRCUITRY LOCKOUT Auto-
| | | | reset after 1 hour lockout due to: |
| | | | - Flame circuit failure. |
| | | | - Gas valve relay stuck open. |
| | | | - Software check error. |
| | | | Reset power to clear lockout. Replace |
| | | | control if code repeats. |
| NO | | Replace furnace control. |
| | | |
| YES | | Check for continuity in the harness and igniter. |
| | | | Replace defective component. |
| NO |
| | Check connections. If OK, replace control. |
| | | |
| | | | Check that all gas valves are turned on. |
| | | | Replace valve. |
| | | | Check for: |
| | | | - Inadequate flame carryover or rough |
| NO | | ignition. |
| | | | - Low inlet gas pressure. |
| NO | | - Proper firing rate. |
| | - Blocked or incorrect carry- over gap. |
| | | |
| YES | | (.045” nominal) |
| | Allow blower to come on and repeat test to |
| | | |
| | | | check for intermittent operation. |
| NO | | Check connections and retry. If current is |
| | near typical value (4.0-6.0 nominal) and |
| | | |
| | | | burners will not stay on, repeat check in high- |
| | | | heat. If burners will still not stay on replace |
| | | | control. If burners operate in high-heat then |
| | | | switch to low-heat, check manifold pressure. |
| | | | If OK, check burner carryover and flame |
| | | | sensor location. |
| NO | | Replace electrode. |
| | | |
| NO | | Replace furnace control. |
| | | |
