fan does not work in "auto" mode on my Lennox Pulse 21 gas furnace
My Lennox Pulse21 has worked fine for the last several years, then I removed the thermostat to paint the walls (just the module; didnt disonnect the wires) and it was off the wall for about 2-3 months. Once I put it back on, the fan would never turn on in "auto" mode. It only works in the "on" mode. I tried a new thermostat and it did the same thing so I put the old one back on.
To run the heater I first turn on the heat, then the fan. Once the house gets to the proper temperature, I then turn the heat switch to "off" and the fan switch off, or actually "auto" mode until it gets cold in the house where then I repeat the process.
Can anyone help me or possibly point me in the right direction?
That furnace has a nasty timed on circuit board to start the fan with the burner and it may be faulty. May be a coincidence that it failed now. It is very expensive/almost obsolete and a difficult/ not DIY/ retrofit/project. Call an EXPERIENCED Lennox Pulse tech.