Air Conditioning on Monaco Coach

[BMB2311]

I have a 2003 Monaco Executive with three heat pumps on the roof. Intermittently they will not cool the coach when in cooling mode. When this happens they typically all will not work.

I switch them over to heating mode and they come on and work fine. This happens when using the generator as well as shore power.

There are two thermostats. One in the bedroom with two zones and one in the living room with one zone. Every indication is that they are OK. I even tried swapping them, to no avail. Also did the reset.

As I said, the problem is intermittent. The heat pumps have been working the last two weeks on 50-amp shore power with no problem, yet prior to that, they wouldn't work for two days straight, also on 50-amp shore power. The start and run capacitors look fine and all of the wiring (visable) looks fine.

[BMB2311]

I recently had my problem correctly diagnosed and thought I'd post the solution in case anyone else might be having a similar problem. When I mentioned the problem to Brett with Alliance Coach at a recent rally he replied instantly that I had a bad ballast in a fluorescent light fixture. Sure enough when turning on the fluorescent under cabinet light in the kitchen area the air conditioners would quit within about 15 seconds. There was no indication of any problem with the light such as flickering or slow to start but none the less the ballast was generating enough spurious frequencies that it interfered with the thermostat voltage. Interestingly enough prior to being told the problem I had also found that when the air conditioners would quit the tank and lp monitoring system would show everything full even when I knew they were empty. We had fought this problem for nearly a year and much hair pulling. The offending light was one of my wife’s favorites when she was in the coach which explained why I never experienced the problem when I was in it alone or when it was stored at home.

[wolfe10]

Some fluorescent light manufacturers such as Thinlite do offer a "Radio Frequency Suppressant inverter to reduce, and in some cases, completely eliminate interference produced by the ballast. "

http://www.solarseller.com/thinlite_ballas...ressed_ballasts

Brett

[tomgauger]

My solution to this same problem was to dump the flourecent tubes (and their ballasts) in favor of LED tubes. Pricey, but brighter and much longer lasting.

Another possible cause of electrical issues is a failing "salesman's switch" relay in the engine compafrtment along with the battery isolator in my '01 Monaco Exec.

I was having flickering lights and HVAC shut-down due to contacts in the relays dying.

I dumped the relays and house DC is wired directly to the 12v house bus in the same compartment with the isolator and the old relays.