Furnace Question
My furnace work ok during the day but late at night after I'm in bed I'll wake up hearing the fan run and get up and no heat turn off and wait a few and turn back on and works. Don't know what's going on any help Thanks'
Forum Discussion
- Rule out the easy stuff first:
What is voltage at the furnace when this happens?
Remove the PC board connections, clean and verify they are tight.
THEN troubleshoot if problem persists. - That is the 3rd Furnace with excessive Gap I have seen (I have worked on a total of 5 furnaces myself
3 had DSI, one worked, (But all I did on that one was filter changes)
The other two.. Had excessive gaps, One was in a house (My parents) and the other is about 12 feet from where I'm sitting just now (RV).
It is now the first thing I check when there is intermittent ignition.
Another cause of "Fires up in Evening but when PM turns to AM it fails is not enough battery when you are boondocking on solar..
Furnace runs on 12 volt.. as the batteries run down the blower slows down, when it slows enough the sail switch ... no longer sails. (or switches) so ignition never is requested. - Just fixed my neighbors furnace that did the same thing. The culprit was a corrode connection on the sparker plus a 1/4 inch gap. It would ignite 90% of the time, but fail during the night when it would kick on often increasing the odds of that 10%.
Cleaned the connection and re-gap to 1/8 inch, and he was back in business. - Without being there to take voltage measurements, I am going to guess that you have a bad high-lmit-switch. And shutting the furnace off allows it to reset itself.
