Rear AC

[Steve Adams]

When we parked last night it was a little warm so the wife turned both AC's on. Everything worked fine.

About an hour later the rear AC started making a hammering sound, it did not appear that the fan was running as I felt nothing from the vents. I turned off the rear AC at the rear thermostat and about 10 minutes later it came on again. I turned off the front AC at the front thermostat and the rear AC turned on again. I set both thermostats at 45 and the rear AC turned on again. I finally turned off the rear AC at the circuit breaker which solved the problem.

Other than get the rear AC serviced, repaired or replaced does anyone know why the rear AC would keep coming on?

It;s got me stumped.

Thanks, Steve

[Frank Bannert]

Why would you set both a/c's on 45 if you didn't want them to come on. Seems to me it would be just the opposite and set it at 80. You lower the temp to cool and raise to warm. Set the one in the back to the off position if that one is making the noise. Sounds as if you have a bad fan motor or the breaker would have tripped. Generally when a compressor goes bad the breaker will trip. Check for debri under the shroud. If you think there is something something wrong with both I WOULD REMOVE THE SHROUDS AND TURN BY HAND WITH THE POWER OFF. and work from there.

Frank

[Steve Adams]

Frank, good call on the thermostat setting but why would the AC keep coming on if it was turned off?

[Frank Bannert]

There maybe a wire that is shorting out. But do you have heat pumps in these units? I would try cutting each one off at the breaker and that should keep the one in the rear from coming on. If not I would look for a short. Maybe at the motor on the roof or at the stats. What type of units do you have?They may be wired together if you have 30 amp. service so it could run both units with the gen, set.

Frank

[Steve Adams]

There maybe a wire that is shorting out. But do you have heat pumps in these units? I would try cutting each one off at the breaker and that should keep the one in the rear from coming on. If not I would look for a short. Maybe at the motor on the roof or at the stats. What type of units do you have?They may be wired together if you have 30 amp. service so it could run both units with the gen, set.

Frank

Frank,

I'll have to get back to you on the specifics. We do have 50 amp service so I don't think that would be an issue. I do have the rear AC breaker off at the main panel. We are heading out again this Wednesday for 10 days so will hope the front AC does not give us any problems. We'll try to get it in for service when we return.

Thanks again for your help. Steve

[Edward Buker]

There is fan position button on these thermostats where the fan can be set to low, med, hi, or automatic. If not set on automatic the fan will run continuously but not the compressor. Not sure about the hammering but if you press the thermostat fan button you can verify that it is set to automatic and rule one more thing out.

Later Ed

[Steve Adams]

Thanks Ed, I'll give it a shot.

Steve