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Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: Old Hippie on April 13, 2013, 07:42:27 pm

Title: Roof Air not working
Post by: Old Hippie on April 13, 2013, 07:42:27 pm
Old Hippie again,
I just got back from a short 100 mile drive in the coach and here is what happened:
I was running the gen set because I thought we might need the roof AC as I had several passengers. I never started the roof ACs but after about an hour or so the generator shut down and a red fault light came on on the dash. We stopped and I looked at the generator panel and no fault lights were on. I reset the switch and the preheat light came on and the generator started. After about 30 seconds it started shaking really bad and shut down, still no fault lights on the generator. When I got back home I reset it again and it ran fine for at least 30 minutes.
I shut it down and hooked up to shore power and tried to start the coach AC. When I tried to turn the thermostat on it appears there is no control power to it as nothing was displayed. It appears there is no 12 Vdc to the thermostat. I checked breakers and the 12Vdc fuses and nothing seems to be tripped or blown. I even looked in the bay electrical box and everything looked fine. The exhaust fan in the bathroom worked and the lights work.
I am not sure if these two are connected or what. I looked through the old postings but did not see anything for the problem I was having.
Any ideas?
Title: Re: Roof Air not working
Post by: Jerry Whiteaker on April 13, 2013, 10:31:36 pm
You have a later coach than mine, but many things might be similar.  Almost all the lights and fans are 12 vdc.  The air conditioners are 120 vac, but the thermostat control may be 12 vdc.  First check that the battery disconnect switch by the door is on which it is if the inside lights and fans work.  It doesn't really disconnect any batteries, but that is what it is called.  I think you have an AC  panel somewhere with a voltmeter and a red and green light or something similar that indicates  AC power is available.  It should give an indication (available or not available) for both shore power and generator power.  If 120 vac not available, then you will have to do some checking to determine the cause.  There is an AC panel with circuit breakers for the air conditioners.  Even if the breakers look like they are on turn them off and back on.  There may also be a main breaker on that panel that might be tripped.  Are other things working like the AC function of the refrigerator, microwave,  or a 120 v outlet?  Sometimes a GFI trip will disable the outlets, but should have no effect on the air conditioners as they each have there own circuit.  If just the generator is not supplying electrical power, although it is running, check the generator itself for breakers that could be tripped.  My generator has done that a couple of times for an unknown reason.  If you are sure 120 vac is not available from either generator or shore power, the house battery charger is not working and the batteries will discharge if lights, etc are in use.  Fully discharging batteries shorten their life.  Hope this helps.