Air Conditioner Hum, advice?

[Jim & Susan]

Well, I think what I'm going to do is put everything back together and try to start the AC unit.

One thing I do remember is that the transformer always hums when the unit is in use. I keep the thermostat "off" and the temp setting way up to around 90 degrees when it's not in use. Once I turn the thermostat "on", the transformer starts to hum. I'm talking about historical function--it's always done this.

Strange how it just started humming on it's own a few days ago. Maybe that start capacitor simply gave up the ghost and caused all of it. I'll let you know how the test run goes.

Jim

[TomW]

Originally Posted by Jim & Susan

... One thing I do remember is that the transformer always hums when the unit is in use...

The transformer is powered anytime your Airstream is plugged in. When it's powered, there's always the propensity for hum... Unless it is mounted in the finest Airstream ever built - the '67 Overlander.

Keep this thread posted; I'd like to help if I can. I love electrical stuff.

Tom

[Jim & Susan]

Would you believe the dern thing kicked right on? The air is not as cold as I would like it, but that's another item for the check list.

[TG Twinkie]

If it kicked right on in the shop. You may have a low voltage problem in the trailer. What size is your shore power cord? Do you have a 30 amp dedicated circuit feeding the receptacle for the trailer?
Maybe you had bad connections where the power for the AC connected to the unit.

[Jim & Susan]

Twinkie, I didn't remove the entire AC unit, just the control box with the transformer and switching devices. I bench tested those and found no issues (that my limited abilities allow).

I have 30 amp run out to the camper. We spent the bucks on that a few years back so that we can use it as a spare bedroom for the frequent visitors we entertain. We have a large family (read: we have lots of kids, that are grown, but still think the 'Stream is cool). Seems somebody extra is always here for dinner. What a great problem to have.

But I digress...it looks like that dang thing is functioning properly. Except for the fact that it needs a little more RJ12. Many, many thanks to all those who helped out. Looks like just a false alarm.

Jim

[Crusty]

Be sure to unplug and replug all connectors in your 30A cable to wipe the contacts clean of corrosion that may have accumulated.

I suspect that due to the sequence of events, your testing operations moved something which was making poor contact and it started working normally again after the connection was restored.