! have a Trane XR 7 year old dual fuel system. The compressor won"t come on when I set heat, the fan does come on. The emergency heat(propane only) works fine. When I set it to a/c the fan comes on but not the compressor. I'm assuming something is amiss with the compressor. I would appreciate some advice. Thank you in advance....Dave

I know the several times my AC won't turn on the problem has been a bad start capacitor...

I now keep a spare on-hand. The next time it won't start I'll try swapping capacitors with the new one before "calling the man"

I don't the compressor comes on with Heat does it?

Our failure during AC was a capacitor failure, it was not expensive to fix.
AC guy found it quickly.

The capacitor is the first thing to check and replace.

Essentially, pull the cover off the unit (after removing power from it... safety first) and take a picture of how the capacitor is connected. Then take it out and bring it to your local parts store and get a replacement.

I know the replacement for mine was only about $20 online... About $75 for the one off the service truck though.

If that fixes your problem then buy another one to keep on hand so you have an immediate fix the next time this happens.

Which fan comes on ? Inside or outside ?

quote:

Originally posted by selogic:
Which fan comes on ? Inside or outside ?

The inside fan comes on, nothing on the outside.

The capacitor was just replaced a couple of months ago.

Is the outside contactor picking up ? Does it have 24 volts being supplied to the coil ? Is the condensate pan in the attic empty ?

[***** THREAD DRIFT FOR SAFETY MOMENT *****]

Capacitors can store an electrical charge. Be careful to safely discharge them prior to touching (accidentally or intentionally) the terminals/leads.

[/***** THREAD DRIFT FOR SAFETY MOMENT *****]

Dave,
You likely need more help than can be gathered from this thread. My advice would be to find someone qualified local to help you get your unit fixed. From the little info you have posted there is no way to accurately diagnose the problem, and I am not certain that it would be safe for you to continue to dive into the unit for more info.

One possible cause is low freon, maybe due to a leak.

The coil in our air handler did this a month or two ago, developed a pin hole.

AC dude replaced the coil assembly. He did not think my suggestion would work -- JB Weld.

List of possible causes:

Low refrigerant, open low pressure switch.
Bad capacitor
Bad contactor
Plugged drain, open float switch.
No low voltage to unit, broken wire.
No high voltage to unit, blown fuse or tripped breaker.

quote:

Originally posted by smschulz:
I don't the compressor comes on with Heat does it?

He has a dual fuel system, heat pump with gas back-up.
So yes, it will run, until the outdoor temperature drops below the switch over point.

If you are wearing out capacitors. you may want to add a hard start kit.

I had a couple added to my systems and the problems went away.

It is nothing more than a second capacitor and relay.

https://www.leonardsplaine.com...oner-hard-start-kit/

Worked well for me, YMMV