What are the gas heat fault codes for Precedent units?
Table 1. Fault Codes
|
Green System LED (Ignition Board) Error Code |
Fault Description | Possible Issue |
| Off | No power or board failure | |
| On | Normal - no call for heat | N/A |
| Slow Flash | Active call for heat | N/A |
| Fast Flash | Not communicating with RTRM | Incorrect Communication wiring or defective Ignition module or RTRM |
| 2 Flash | System lockout - failure to sense flame | "BLUE" wire from transformer low voltage is not grounded to sheet metal. "B" terminal on board not grounded to sheet metal. Gas valve did not receive 24 volts to coil. Ignition board did not furnish 24 volt signal to gas valve coil. Flame sensor defective. Flame sensor wire open or disconnected. Flame sensor wire shorted to ground. Burner cross-overs are rusted and/or restricted. Defective ignition board. |
| 3 Flash | Pressure switch failed to open when CBM stops or closed when CBM starts | Switch contacts closed during heat cycle start-up. Pressure switch will not close after combustion blower has reached full speed. Pressure switch hose is restricted, pulled loose, or leaking. Flue box hose fitting is restricted with debris or rust. Defective ignition board. Bad CBM. Blocked airflow, |
| 4 Flash | TCO-1 or TCO-2 (high temperature limit) circuit open | Wire terminals on switch are corroded and not allowing electrical path. Low airflow due to excessive duct static. Low airflow due to dirty filter. ID Blower is defective or not being energized. Switch has permanently open contacts. Wire(s) from switch are broken. Defective ignition board. |
| 5 Flash | Flame being sensed, but gas valve not energized | Gas valve sticking in open position. Gas valve remaining energized after heat satisfied. Defective ignition board. |
| 6 Flash | Flame rollout (FR) circuit open | Combustion air flow is restricted. Look for debris in flue duct. Heat exchanger tube fractured near burner input. Flame blowing back into combustion chamber. Gas orifice spuds not aligned with burner. Combustion motor intermittently fails during heat cycle. Turbulator broken and has been drawn into heat exchanger tube. |
| 7 Flash | W2 call before W1 (Electro-mechanical units only) | Wired wrong at unit's low voltage connection. Wired wrong at thermostat. Thermostat possibly spliced wrong between unit and thermostat. W1 and W2 terminals on ignition board wired wrong (swapped). |
Resetting the Control
Method 1
To reset the system from the space, turn the "Mode" selection switch at the thermostat to the "Off" position. After approximately 30 seconds, turn the "Mode" selection switch to the desired mode, ie...Heat, Cool, or Auto.
Method 2
To reset the system at the unit, cycle the unit power by turning the disconnect switch "Off" and then "On".
Method 3
The ignition control will reset automatically after 1 hour in "Lock-up" mode.
WARNING:
Information in this article is intended for use by individuals possessing adequate backgrounds of electrical and mechanical experience and who comply with all federal, state, and local laws, rules, orders, or regulations related to the installation, service, or repair of a heating or central air conditioning product. Any attempt to install, service, or repair a heating or central air conditioning product may result in personal injury and/or property damage. The manufacturer or seller cannot be responsible for the interpretation of the information contained herein, nor can it assume any liability in connection with its use.