No HVAC power

[Inspector 71]

Had A/C on today with camper parked in my driveway and plugged in for power. Cooled things down nicely. Then it stopped working. No A/C, no fan, no nothing from things controlled by the thermostat.
A/C breaker wasn't tripped, but I flipped it off & back on to make sure. 2 amp fuse inside the thermostat appears to be OK. GFI outlet that the camper is plugged into was tested and reset. What should I be looking at next?

[imjustdave]

It could have frozen up, the coils that is like ice cubes. But I think the fan would work still. Does it smell? If it's a new unit maybe check the wires or it could be a trip to dealer to have them look at it and test in depth inside.

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[Grumpy]

Did you check the 12v fuse for the thermostat?

[justman]

Did you check for power at the internal breaker...the one inside the RV? If it's not getting power, that'd help narrow down your search.

Also, I'd be really leery about running the A/C for an extended time on a 15 amp circuit...which is what I presume you have your GFCI connected to. They're made for 15 amps and can go slightly above for brief periods before the breaker trips. Your A/C is most likely taking every bit of power that circuit can deliver. Run it too long and it'll be plenty warm. Or hot.

[ALJO]

You might have fried the A/C compressor on a 15 amp breaker and #14 wire. The voltage drop would be to high. In the RV it is a 20 Amp breaker for the A/C and the shore power GFCI is 15 amp which would kick first.

[Inspector 71]

Originally Posted by Grumpy

Did you check the 12v fuse for the thermostat?

It appears to be OK.

[Inspector 71]

Originally Posted by justman

Did you check for power at the internal breaker...the one inside the RV? If it's not getting power, that'd help narrow down your search.

Also, I'd be really leery about running the A/C for an extended time on a 15 amp circuit...which is what I presume you have your GFCI connected to. They're made for 15 amps and can go slightly above for brief periods before the breaker trips. Your A/C is most likely taking every bit of power that circuit can deliver. Run it too long and it'll be plenty warm. Or hot.

How would I do this? Pop the breaker out and put a meter on the bar of the RV breaker box?
I built the garage 15 years ago, I don't recall so I'll have to go out and check how many amps the circuit for that particular outlet is. The garage has it's own sub panel. The garage refrigerator might also be running off that circuit. It's all wired with 12/2.

[justman]

Originally Posted by Inspector 71

How would I do this? Pop the breaker out and put a meter on the bar of the RV breaker box?
I built the garage 15 years ago, I don't recall so I'll have to go out and check how many amps the circuit for that particular outlet is. The garage has it's own sub panel. The garage refrigerator might also be running off that circuit. It's all wired with 12/2.

Good thing you did the wiring with 12/2. Standard GFCIs are only rated for 15 amps unless you bought a 20 amp one.

You should be able to pull the cover off your breaker box. That should get you access to the breaker and the negative and grounding bar. Should be able to take a reading using a multimeter on the breaker lug (screw/clamp the wire is tied into on the breaker) and the grounding or negative bar. Should show at least 115 volts.

[Grumpy]

Originally Posted by ALJO

You might have fried the A/C compressor on a 15 amp breaker and #14 wire.

Very doubtful, but the fan would still run.

[Grumpy]

Originally Posted by Inspector 71

It appears to be OK.

Pull the thermostat and check the wiring it has been known to come loose in the wall. (connected with wire nuts) Also there may be another fuse (in-line) in the wall.

[Inspector 71]

Originally Posted by Grumpy

Pull the thermostat and check the wiring it has been known to come loose in the wall. (connected with wire nuts) Also there may be another fuse (in-line) in the wall.

Another possibility. I did see the bundle of wires tucked inside the wall but left them alone.

[Inspector 71]

I did attempt to check things out a little further this morning. Couldn't get the cover off of the breaker box so I gave up on that. All wire nutted connections behind the thermostat are good.
I removed the grate in the ceiling to check things out. A click can be heard when the thermostat is moved from from the "cool" to "off" positions. A check of the terminal board in the ceiling shows 27.6 volts on the GH terminal, which leads me to believe that there's power to the A/C unit.
So from here I'm thinking it's time to have a professional check the thing out.