On Fri, 29 Nov 2019 15:23:26 -0500, wrote:

On Fri, 29 Nov 2019 12:00:59 -0500, Ralph Mowery
wrote:

In article ,
says...

The heat will not run unless the fan is on and depending on the
thermostat base, you might have to turn the fan switch on to get heat.
I am not sure about furnaces, I haven't seen one in 35 years but that
is how air handlers work. I do know you can run most heat only
furnaces on a 2 wire thermostat (just reading the instructions for
thermostats). He is definitely in the situation where poking around
with a meter (even a 24v test light) and looking at the wiring diagram
is in order. Just throwing parts at it and trying to get lucky is
silly.



This is not a furnace, but a heat pump.

The fan on the air handler runs when it is calling for heat. It is the
out side unit that is not running. The relay for it has no voltage
going to the coil that tells it to pull in and run the compressor and
the fan for the outside coils.

The thing acts up so infrequent it is difficult for me to do much but
just want to get it started. I hate cold weather and seems like my
brain freezes up when cold. I call anyting below about 50 cold being in
the middle of NC.


The LED indicator will still be a way for a quick peek without having
to get your meter out. I would start with it on the white wire from
the thermostat inside the air handler and get that out of the picture.
The first rule of trouble shooting is "can you draw a circle around
the problem"? You want to get as much as you can outside that circle.
You already seemed to have eliminated the condenser since you don't
have the pick shot to the relay. If you eliminate the thermostat and
wiring into the air handler you are getting pretty close to that
control board. Do a visual inspection of all connections before you
buy anything.
+1