Hi all,

Finally time to use the heater in FL. Problem is the blower fan won't kick on with the heat. But it comes on with the A/C and when i turn it on manually.

A/C model is a Payne Model PH15NA048, I installed the thermostat 1-1/2 years ago and it worked fine last year.

Any ideas?

Thanks.

 

There are a couple of possibilities. If it's a typical PSC motor, it often is multiple speeds. Often the heating and cooling modes use different speeds, so one possibility is that the winding that corresponds to the speed used for heating is burned out. Another possibility is that there is a fan relay being used that is defective, although that is likely to affect the fan in cooling mode as well. It's also possible that the capacitor is defective, although again I would expect that would affect the fan in cooling mode as well.

The first thing you should do is to check to see if the blower motor is getting voltage. With any luck, you should find a wiring diagram for the furnace showing how the motor is wired. To measure the voltage, you'll need an AC voltmeter (multimeter). Also, there is often an interlock switch on the furnace door that turns off the power when the door is removed. You'll have to tape that closed to get power.

 

oops.. I messed up this post, see the next one.

 

jmandawg
The return is in the attic and is a pain to get to. So does the thermostat turn on the fan or does something else at the heat pump turn it on after the heat pump is started?

I took the side door off the return and this is the wiring diagram on the Fan:


And here is what the electrical looks like in there, i see a relay and some other stuff:


So i should start it in heater mode and check the wires going into the fan? There are quite a few going into the fan.

 

The G terminal on the thermostat controls the blower. If you have a voltmeter, check the voltage between the R terminal and the G terminal when the thermostat is calling for either heat or cooling. The voltage should read 0VAC. If there is something wrong with the thermostat, you would read ~24VAC between R & G when calling for heat/cooling.

 

What thermostat do you have? Is it configured for electric heat?

 

I figured out the problem. There was a slider switch inside the thermostat, and it was set to gas instead of electric. Once i set it to electric it started working correctly. I could have sworn it worked last year so i don't know if the switch got changed or what. Maybe i didn't use the heat at all last year. Anyways, i guess that's what i get for not reading the manual when i installed it...

Thanks for the help everyone!

 

That is great news

Happy to be of assistance.

 

Yep you hit the nail on the head Houston. Thanks again!