On Mar 22, 3:53 pm, "Zyp" wrote:
stoneattic wrote:
Does anyone have an idea as to why the fan on my heater/AC would run
constantly when the thermostat is set to have the fan in "Auto" mode
but not run at all when in "On" mode?

The whole story:

My fan was running all the time regardless of thermostat setting,
including heat and AC off. I disconnected the green wire from the
thermostat and it kept running. From everything I read that indicated
a stuck fan relay. When I looked at the fan really it was cooked,
burned plastic, etc. So I replaced it with the same model. I'm
pretty sure I wired it exactly the same, I took notes, etc. So now I
got the weird situation described above. I picked up a new thermostat
thinking that maybe the burned relay took out the thermostat but it
does the same thing. That makes me believe I did screw up the wiring
but after much reading and checking and rechecking the wiring looks
right. Does any know what could cause this?

thanks

You're right. You messed up on the wiring. Check the units blower door for
the mfg.'s wiring diagram, and compare notes. I think you'll find you've
mis-wired the relay. And BTW, if you're not careful, you will let ALL THE
FACTORY SMOKE out of the motor and it won't run at all.

--
Zyp

I'm pretty sure something is not wired right, despite my best effort.
There is no wiring diagram in the blower units door unfortunately.
Assuming I have the thermostat connected correctly...

What I've got is..
power coming in (white and black and bare "ground")
red and black on the N/O side of the fan relay, a black and a white on
the coil of the relay
a blue and a white going to the oil burner motor
a red, an orange, and a black going to the fan limit control

any ideas?