Furnace doesn't always light
Is there a good thread for troubleshooting furnace problems? Mine is not quite 3 years old and has worked fine until this week. Sometimes when the thermostat calls for heat the fan comes on but the...
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Me and my big mouth - a week after I posted that the problem had gone away, it's doing it again. This time I pulled the cover off when the furnace was in 'failed' mode and the controller board was flashing ONE = sail switch or limit switch.
I guess I could easily replace the sail switch. The limit switch is pretty buried. I'm going to put my DVM on the sail switch leads next time the furnace croaks. Problem is, I have to catch it in the 15 seconds that the fan runs AND the furnace doesn't light to see if it's closed.
BTW, the airflow is good on both the combustion side and the heating side. It's only 2.5 years old and very clean.
I guess I could easily replace the sail switch. The limit switch is pretty buried. I'm going to put my DVM on the sail switch leads next time the furnace croaks. Problem is, I have to catch it in the 15 seconds that the fan runs AND the furnace doesn't light to see if it's closed.
BTW, the airflow is good on both the combustion side and the heating side. It's only 2.5 years old and very clean.
