|One LED flash that stays on continuously
||No signal from the thermostat.
||Turn off the unit’s power and check connections.
|Single LED flash
||Furnace lockout due to an excessive number of ignition retries (3).
||Locate and correct gas interruption. Reset by lowering it for 20 seconds and then raise it back, furnace will reset itself after one hour.
|Two LED flashes
||Draft inducer is not operating or the pressure switch circuit has closed.
||Replace the induced draft blower pressure switch, or repair the short.
|Three LED flashes
||The pressure switch is open.
||Pressure switch may need to be replaced.
|Four LED flashes
||Pressure issue. High limit cut-off due to faulty wiring or bad filters.
||Replace or clean the air filter; clean drain tubes of moisture or debris; may have an open limit switch that requires a jump, ensure not to run it with the main switch bypassed.
|Five LED flashes
||The unit is sensing a flame without a call for heat.
||Might be the result of a slowly closing valve. Turn off the gas until the valve is fixed.
|Seven LED flashes
||Faulty flame sensor.
||Flame sensor might be dirty or placed too far from flame. Clean if dirty, replace if defective.
|Continuous LED flashing
||Polarity of volt power is reversed.
||Review wiring diagram to correct polarity.