Lennox G51MP intermittent heating issues

Old 03-18-23, 11:11 AM
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Lennox G51MP intermittent heating issues

I have a lennox g51mp that is around 7ish years old. Last moth had issue where it wouldn't fire and seemed like condensation drain issue. Cleaned that up and seemed to fix it.

Came home from out of town and found my inducer fan running but no heat and house down to 56. Shut thermostat off and back to on no change. With thermostat off I cycled power to furnace. Once I turned back on the inducer immediately started. When I kill power for 10-15 minutes then the inducer doesn't start immediately. Pressure switches all tested good with multimeter. It ran all night friday without issue but Saturday am it was doing it again and how was down to 59. It took about 10-15 min with power off to furnace for it to work correctly again.

When it is stuck with inducer running constantly the lights are showing normal operation.

I am thinking control board issues or thermostat issues. Any ideas?
Old 03-18-23, 09:48 PM
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Are you observing both LED's with a simultaneous fast flash ?


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