Integrated Control Diagnostic Codes - Lennox MERIT ML180UHE Installation Instructions Manual

Integrated Control Diagnostic Codes

RED LED
Flash Code
Off No power to control or board fault detected
On Board fault detected,
1
Heartbeat 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
Primary or Secondary Limit Open or Watchguard Mode − Limit Switch Open longer than 3 min-
7
utes
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
Note
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,
Note
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.
Diagnostic Codes / Status of Furnace
Notes
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