I have a problem that has me stumped, hope somebody has an answer to this problem. I lost power to the coach with the generator running the other night. Looked at the usual problems like circuit breakers (both coach and generator breakers). Next I checked the generator transfer switch and discovered no power to the coach with the generator running...so problem solved right... jumped out the generator transfer switch that night and got all my electrical outlets working but not my air conditioners. Next day, hooked up the shore power and everything works including the A/C. I ordered a generator transfer switch and installed it a couple of days later. I now have power to all my electrical outlets, fridge, micro and TVs but still not the air conditioner with the generator running. Again, everthing works fine on shore power including my A/C. Also, the fans on the air conditioner works with the generator but the A/Cs show the red shed light and will not go to green or cool. Facts on the coach: Fleetwood Southwind, Workhorse 8.1, 30 Amp service, Onan 5500 generator. Also the converter is working fine. Can't think of anything else to add but would appreciate any suggestions on what to look at next. Thanks in advance for any help on this one.

The blower on all RV air conditioners that I have ever looked at, get their power for both the compressor motor and the blower motor from the exact same wires. The power leads run from a circuit breaker up to the a/c unit where there is a common junction point and is split into two circuits at that point. I suppose it might be possible that yours uses each phase of power as a separate 120V leg and uses two 120V motors, rather than two of them at 240V each.

If that is the way that yours is wired, then you might have one phase that isn't working?

Kirk
First of all thanks for answering, but if that is true why do I have no problems with the a/c's when I am on shore power. BTW, I called Fleetwood and they were of absolutely no help, so I called Camping World and CW said that if I had no problems when on shore power and I replace the automatic transfer switch than they were also stumped but would call Fleetwood and see if Fleetwood could help them...got my answer today... "George, you are correct...fleetwood was of no help" at least CW agreed to look at the problem if I brought the coach in and they would try to trouble shoot the entire system. I thought I was a half way decent shadetree mechanic but this has me really stumped...if I get it figured out I will post my findings. I guess I should start over and chase the wiring from the generator to the a/c again maybe I missed something. I am wondering when the auto transfer switch went out could it have done something on the DC side that does not affect the 120v side? and of course what could that have been since everything else works on generator and everything works on the shore power. Wish me luck...been fulltiming just over a month and really do not need this but the adventure is getting interesting and things get a little more urgent when you don't have a pad beside you house to park on and another house to live in while you work on this unit.

....rip out the transfer and add a male plug to the coach end of the chord and female plug to shore power and generator cords....bet the problem will be fixed.....transfer switches are a PIA and they do some funny things now and again....I will not use them anymore.... plug in the shore power or the generator but you can't plug in both at the same time.......geofkaye

Is it possible that your generator is not putting out the correct voltage or frequency? Could there be a protection circuit built into the air conditioner compressor circuit that is preventing it from coming on? I can't think of any other reason why the fan would work but not the compressor. This one is strange......

quote:

First of all thanks for answering, but if that is true why do I have no problems with the a/c's when I am on shore power.

To answer that would be a pure guess on anyone's part since the wire that supplies your air conditioner is exactly the same wires from your 120V distribution panel to the unit.

The way that a motorhome is wired is that there are two supplies which go to your auto-transfer device. From it there is usually one set of three wires that go to the power distribution panel which supply all power to the entire RV no matter where it comes from. The power distribution panel for the RV and all wires and breakers from that point are exactly the same no matter what is supplying the power.

If I were there, I would first verify that what I understand you to be saying is accurate. I would then get my meter out and trouble shoot the system since it sounds to me as though you have a pretty unique problem.

I made a living from electrical service work for 40 years before I retired, so this is the best that I can suggest. I am sure that your RV is wired in this way, unless someone has modified it at some point. If you are not the first owner, that could be part of the problem. It that is the case, all bets are off and you will need to trace wires.

An Onan 5500 should be more than enough to power things as it can supply about 48A total. In thinking about what you must have, the genset possibly supplies two separate bus bars in the distribution panel, since my 5500 has two separate output breakers, could it be that yours does also and one of them is not closed? or perhaps defective? I would expect the air conditioner to get power for both the compressor and the blower from the same bus bar of the distribution panel, but it could be that it does not. If one side should be open, I would expect there to be something in addition to the compressor that won't have power, but you might not be aware of it. If you have this type of set-up, that could cause the blower to run and not the compressor.

One other thing that I just noticed in reading your posts again is that you say "the A/Cs" which makes me think that you must have two of them? In this case, you probably have two phase service from the genset and single phase from the shore power cord. That would also mean that your transfer device would be wired differently than I am familiar with, since the shore power would have one hot, one neutral and one ground, while the genset will have two hots a neutral and a ground. I can't recall every having seen one wired in that way, but I do know that they do exist.

Wish that I were closer to you as this one really fascinates me and I'd love to take a shot at it.

This message has been edited. Last edited by: Kirk,

OK my 2 cents. I had a problem like yours on one of my uncles tour buses. A/C ran on shore power but would not start compressor with gen. although A/C fans ran ok. turns out generator was going bad and did not produce enough amps to start compressor.

Dr.Kool, 43 years in the A/C business.

firepup,

Do you have a 30 amp or a 50 amp shore cord? Did you recently purchase this unit? What is your generator make/model?

quote:

Also, the fans on the air conditioner works with the generator but the A/Cs show the red shed light and will not go to green or cool.

Sounds like you have a load management panel that doesn't allow both compressors to come on at the same time unless you're connected adequate shore voltage.

My guess is the voltage or frequency of your generator is slightly off - enough to make it look like poor shore power - and the load shed panel is refusing to start the compressors.

Your load management panel may have a wire that runs to either a contact on the transfer switch or the generator input to tell the panel when you're running on the generator. If so, the compressor management feature will either be defeated (allowing both compressors to run simultaneously) or the voltage acceptance range widened when you're on the generator.

This message has been edited. Last edited by: Lou Schneider,

Oh s___! I just replied to each of you and lost it all with this dang laptop. Here it goes again,
Kayrivercity: I am at wits end and may follow your advice but since I have to have my rear slideout topper replaced at CW they said they would look at my auto transfer switch and problems with the electrical when I take it in for the other problem. stay tuned!
Rif: I checked the generator and I am getting plenty of power. I have not checked the a/c's to see if they have a built in circuit protection but if that was the case why would it work on shore power with no problems???
Kirk: You are correct once the power goes through the auto transfer switch it does make a difference from where it came.
I did get my meter out and have checked and rechecked my transfer switch, I am getting power to the chassis from both the generator and shore power.
I do have two ac's and they are controlled by an electronic climate control device which acts like an ECM in that it will shed power to the air conditioners when the load is over 30 Amps counting all power usage in the coach. Since the a/c need about 26 Amps to operate and with any other power on they are cycling (sheddng) all the time when on shore power. On generator it is different, it sheds power only to the front a/c while the rear a/c remains on all the time. But I have never seen the power shedding when using the generator because as you stated it has more than enough power to provide power for everything in the coach. It also has a 5 A dc fuse which is OK.
The auto transfer switch has basically grounds for all incoming wires, a neutral side for the generator, shore power, and chassis; the other side has a hot for the generator, shore power and chassis. Again I have double checked and I have power to the chassis from both the shore power and generator. Also, the generator does have two circuit breakers and I have metered both of them - no problems.
I am not aware of anything not working on generator or shore power but will meter all the outlets, fridge, water heater, furnace (which I have not checked)and anything else I can think of. Please keep your thinking cap on and let me know if you can think of anything else I can check out.
Dr. Koolwickedwanda: Checked the generator and it is working fine
Jim Epting: I have a 30 Amp shore power, I bought this unit new in 2003, and the make and model of the generator is Onan 5500.
Lou Schneider: I don't see any other wires on the auto transfer switch, I don't have a load management system other than what I talked about earlier and like I said I don't see any wires. Again the power coming out of the generator and to the chassis from the generator in the auto transfer switch is good.

Again, let me thank all of you for taking time to scratch your heads. I am beginning to think it is something so simple that I over looked it but I am just too close to the problem to realize it or just to dang gone dumb. Please keep on thinking about this if you have time... my slide cover should be in next week and I would hate to pay CW for something I should be able to do myself.

I assume that "red shed light" is located on the power management unit and not the a/c? If this is correct, it would seem that the cause of your problem has to be the power management but that could either be from an issue with it, or from an issue with the power from the genset.

Since it works normally when on shore power, I tend to think that there must be some issue with what it gets from the ATS when on the genset. When I used to trouble shoot for a living, I always looked first and closest at what had changed since it last operated properly. That does seem to be the ATS, or the connections from it.

When you do find the problem, please do return and let us know what it is!

Kirk
Thanks for staying with me on this and I will post the answer once I get it figured out or pay someone smarter than me to figure it out. I will check out the power management system but wonder why I would have a problem there if everything works on shore power? As your stated before, once power leaves the Automatic transfer switch it is makes no difference where it originated.
I can recheck the ATS and its wiring since that is what I replaced, maybe the new one was faulty.

OK checked the wiring one more time before taking it in to have a technician look at it...I opened a junction box next to the generator and noticed that one of the hot wires was not taped very well and the wire nut was twisted backward.... I undid the rest of the tape and just as a couple of you suggested one leg was not connected.....I rewired and taped the wires and now I have a/c on generator. Thanks again

Aaahhhh. Another loose disconection......You're just lucky you didn't let the magic smoke out.

George (or Pat),

You may also be lucky you didn't get involved with a so-called "technician." I've not had any experiences with CW, but I've surely read about many.

Good boy!