I have a gas pump furnace that has been switched over to propane prior to me moving in.
Replaced filters and thermostat, checked all fuses and junction box. a/c works and fan only works but when I turn it to heat - I get nothing. I removed panel and reset the switch - it stayed on for about 3-4 minutes and blew warm air but then turned off. Can anyone help me.

Has this unit ever worked correctly since the conversion?

Is the propane tank full?

Model and Brand of furnace?

Gas pump furnace?? Is it a heat pump with gas back up?(Duel fuel)

Was the reset in the outside unit?

I got it! I found the LED light which stated to check the pressure switch. I pulled the vacum hose off and found water inside. Tighted the pressure switch to the back panel, it was loose and leaning towards one side. Started it up and works great. Thanks for responding to my request and all the others. Even though it is not your problem you help a lot of people. Again thanks!