[marric]

I have a Heil model #H9MPV075F12C1. The draft motor turns on, ramps up and then shuts off. It does this with no call for heat, no LV wires connected. It does this on and off, no rhyme or reason. I already changed circuit board, which Heil said was the problem, but still continues.

 

[beenthere]

Has any electrical work been done in the house in the 6 months or so. If so, check for bad grounds in the panel box.

 

[Dr Heat]

Sounds like a limit switch failing.

 

[flashheatingand]

I once dealt with a no cool call for a friend. Furnace was in the attic. The attic was so hot that it actually opened a roll-out switch.

That was a weird one.