Quarantine AC unit help Please

Today it finally got warm enough to kick the AC in and it didn’t do squat. As far as I was aware the heat pump was working when cold but it’s possible it’s doing a lot of emergency heat instead. Compressor is a new (refurb) unit that was installed a little over 2 years ago. Anyways. I went out to the unit and pulled off the plate and saw these 2 wires (black and white) hanging not touching anything else and look like they should be. Large black and brown wires have nothing connected to them. Are they supposed to be connected? The wiring diagrams I find honesty suck...

picture:


For reference it’s a trane xe1000.
Help please!

 

It certainly looks like the white was connected to something, and my guess is to the black, which is still under the wire nut. And that I don't get. So don't put them together unless you can follow the diagram for them or get a pro there.

 

Figured out something else which is its flashing an error code on the external unit which is for External lockout. Guessing there’s a short or those wires need to be hooked up. The wiring from the house to the unit is crap and very brittle.

 

I had an A/C technician here today. He was so good at his job that the unit was more broken when he left than when he got here. Good luck with yours.

 

Go to your thermostat and look at the wiring connections. The important connections are the wires connected to Y, C, and O, and G

Y is the compressor contractor. (Turns on compressor and outdoor fan). C is common from the control transformer in the air handler. O is the reversing valve which is energized during cooling. G is the fan relay in the air handler.

All of the switching is done by the thermostat. The air handler doesn’t control the outdoor unit besides that it’s the 24vac source.

 

I’m actually wondering if it may be the capacitor. It’s not bulged but I set it to cool and the pipe to the house isn’t cold like it should be. Either that or the compressor is dead which means I’m looking at a new system.

 

Is the compressor contactor coming in at all??

 

How old is the system?

 

I got nothing but my post count is way behind.

 

gonna check this after a couple meetings I have this morning. The fan kicks on and I THINK the compressor is trying to. Makes me wonder if the compressor side of the capacitor has died but I didn’t have a lot of time to investigate last night. I always seem to notice issues at night and fumbling in the dark after a long day always sucks. So mid day I’ll go check it out.


The system is old minus the reman compressor. It honestly does need to be replaced. But doing that in a quarantine situation doesn’t seem like the smartest idea. As it’ll require a bit of work inside my home. Plus I really was hoping to blow my COVID stimulus on something more fun than a new AC unit.

 

If the condenser fan runs but it doesn't cool, you may have a bad capacitor. The compressor motor is thermally protected so you'll be able to hear the compressor attempt to start for a few seconds before the overload trips.

Leave it off for an hour or so to ensure it's cool. Then turn off the outside unit at the disconnect and initiate a call for cooling. Power the disconnect when you're next to the unit. If you hear the compressor groan when it tries to start, it's likely your capacitor. You can also check the motor windings if you have a meter. Just set it to ohms and check between each of the three windings. The resistance of the lower two values should be equal to the resistance of the highest one.

It's unlikely that the compressor is shorted to ground since you're not tripping the breaker.

 

Last time the compressor shorted to ground and that nearly tripped my main breaker when it happened. I have a good meter (Fluke) but it doesn’t have a function to check the capacitor. The weather has been so mild I haven’t noticed the system working abnormally until it didn’t cool at all. I have a couple spare capacitors so I can throw one on easily if it’s bad.

 

I fried the fan relay on my AC board. Stinks

 

delay on timer maybe?
Maybe it’s shot.

 

Good thinking except that the delay interrupts the contactor which also controls the condenser fan.

 

This is a pretty dumb system as it’s old. I should be able to turn on then put the disconnect in while next to the system to hear it kick on. I’ll check the contact switch and then if no go check the capacitor.


Haven’t had a chance to check yet as I’ve been busy teleworking this morning. Hoping to catch a break when I get home here in a few.

 

Yes. You'll hear the contactor hum since it's powered by the 24v control transformer in the air handler. When you plug in the disconnect it should try to engage the compressor.

Are you sure your Fluke meter won't measure capacitance? Usually it's combined with resistance or continuity and you have to push a yellow button to switch between functions.

 

Hmm I’ll look.

 

Nice! It’s a blue button but it works. Never realized that!

 

contactor switch works when told to energize so.... I’m thinking potentially bad compressor. Crap!