Lennox Gas Furnace Error Codes

EL180DFE series units are mid-efficiency gas furnaces used for downflow applications only, manufactured with Lennox Duralok heat exchangers formed of aluminized steel. EL180DFE units are available in heating capacities of 44,000 to 110,000 Btuh and cooling applications 1.5 to 5 tons. Refer to Engineering Handbook for proper sizing.

The integrated control is equipped with an LED light for troubleshooting

Off -No power to control or board fault detected

On- Board fault detected,

Heartbeat1- Control powered – displayed during all modes of operation if no errors are detected

1 Reverse Line Voltage Polarity

2 Improper Earth Ground

3 Burner failed to light, or lost flame during heat demand

4 Low Flame Signal – check flame sensor

5 Watchguard – burner failed to light, exceeded maximum number of retries or recycles.

6 Not Used

7 Primary or Secondary Limit Open or Watchguard Mode  – Limit Switch Open longer than 3 minutes.

8 Rollout Switch Open

9 Pressure Switch failed to close or opened during heat demand

10 Watchguard – Pressure Switch opened 5 times during one heat demand

11 Pressure Switch stuck closed prior to activation of combustion air inducer

12 Flame Sensed without gas valve energized

13 Low Line Voltage


Note 1

A ”Heartbeat” is indicated by a ”Slow Flash” – 1 sec on 1 sec off, repeating


Error codes are indicated by a ”Rapid Flash” – the LED flashes X times at 1/2 sec on 1/2 sec off, remains off for 3 sec, then repeats

Last 10 error codes are stored in memory including when power is shut off to the unit. – To recall, press and release button, most recent will be displayed first, LED off for 3 sec, then next error code is displayed, etc. To clear error codes, depress and hold button longer than 5 seconds.


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