Community Forums

SoupsOn · 06-10-2022, 12:19 PM

Troubleshooting the rear AC unit revealed that yes, it's getting power, but only half = 46vac.
I discovered rodent damage to a lot of wiring after my purchase, so that's an ever-present possible problem.

How do I discover the wire's run so I can find the issue?
The coach is built on steel frame and the wire disappears into the ceiling, of course, so how do I track the course?

If I've got bare wire somewhere, obviously that's an extra problem...

Please explain how it's POSSIble for it to carrying half power? (It's Romex)

Thanks!

(Wired up the AC unit with a female plug to plug it in directly, and it does function. There's the good news. It did trip the 10amp breaker, so assuming this becomes the 'fix' while I'm stationary, that'll be a task for another day.)

bigb56 · 06-10-2022, 12:35 PM

Quote:

Originally Posted by SoupsOn

Troubleshooting the rear AC unit revealed that yes, it's getting power, but only half = 46vac.
I discovered rodent damage to a lot of wiring after my purchase, so that's an ever-present possible problem.

How do I discover the wire's run so I can find the issue?
The coach is built on steel frame and the wire disappears into the ceiling, of course, so how do I track the course?

If I've got bare wire somewhere, obviously that's an extra problem...

Please explain how it's POSSIble for it to carrying half power? (It's Romex)

Thanks!

(Wired up the AC unit with a female plug to plug it in directly, and it does function. There's the good news. It did trip the 10amp breaker, so assuming this becomes the 'fix' while I'm stationary, that'll be a task for another day.)

How are you measuring power, with a digital meter? Are you measuring from hot to ground, neutral to ground to see which one has the voltage? Is the 46 volts steady or does it jump/float around? Also, what do you mean by a 10 amp breaker, they don't normally exist on US circuits, 15 is generally the smallest.

Persistent · 06-10-2022, 04:19 PM

the rear AC unit revealed that yes, it's getting power, but only half = 46vac.

Please explain how it's POSSIble for it to carrying half power? (It's Romex)

Low voltage under heavy load mean high resistance in the circuit. It could be in hot leg or neutral leg. This assumes you measured from hot to neutral wire.

Some A/C have a control module. The control module runs on 12 volts and controls the 120 volts. The fault may be there. Measure the voltage there.

Don't forget to measure the voltage at the breaker box. If it is 46 volts there, it could be the breaker.

This condition should blow a circuit breaker or fuse since compressor motor will draw high current for a long time. This is also damaging to the compressor motor because stalled motor draws high current and generates high heat. Insulation melts or cooks.

Sometimes the motor will run OK after power is restored. After a few hours the motor may self destruct. Hopefully the fuse blew before heat damage.

Corroded connections
Loose connections
Frayed wire

bigb56 · 06-10-2022, 05:41 PM

Won't know much till we get more facts but my guess is that the neutral is open and he is measuring between hot and neutral and thus seeing 47 volts on a digital meter. Measuring from H-G and N-G will prove or disprove. A breaker cannot limit voltage, it is either there or not. Same with a loose connection, it will read full volts until a load is placed on it. The OP appears to be MIA at this point, hope he is OK.

D Gardiner · 06-10-2022, 10:14 PM

As others have said, triple check the way you are measuring the power. Also,.. are you testing the power with the unit running?

Either way. You may want to disconnect the A/C from the coach wiring, and run an extension cord directly to the A/C and test it.

If all works well then, I would replace the coach's Romex wire to the A/C.

SoupsOn · 06-10-2022, 10:42 PM

Quote:

Originally Posted by D Gardiner

As others have said, triple check the way you are measuring the power. Also,.. are you testing the power with the unit running?

Either way. You may want to disconnect the A/C from the coach wiring, and run an extension cord directly to the A/C and test it.

If all works well then, I would replace the coach's Romex wire to the A/C.

Thanks. Yes. It was upon plugging into an extension cord that the AC ran for me for the first time.

I didn’t test the power coming to the unit myself. I will pass along the points made and bring back info.

The ac unit doesn’t function at all when hardwired into the house wiring. I’m assuming the power available (46vac) isn’t adequate to get it to do anything at all.

No, there has been no testing of the power with the unit running.

SoupsOn · 06-10-2022, 10:48 PM

Quote:

Originally Posted by bigb56

How are you measuring power, with a digital meter? Are you measuring from hot to ground, neutral to ground to see which one has the voltage? Is the 46 volts steady or does it jump/float around? Also, what do you mean by a 10 amp breaker, they don't normally exist on US circuits, 15 is generally the smallest.

Thanks!
I’ll work on getting more answers regarding the specifics of what was tested.
What I do know is that the number was steady. And the breaker is 10 amps. Surprised me too. As I dig into this further I’ll be evaluating replacing at least the ones that run the AC units.