Losing air conditioners while running generator

motohomo · 06-15-2015, 03:33 AM

I have a 2013 vista 35b with 2 rooftop ac units and an onan 5500. When we are under way traveling down the road with the generator running and 1 or both a c units running, suddenly the a c cuts off. The generator still runs fine. I thought it was a faulty transfer switch and replaced it. Anyone have any ideas? Btw...this does not happen when sitting still, only when traveling down the road.

grtharris · 06-15-2015, 06:40 AM

motohomo, does the EMS Monitor Panel indicate?

SuperGewl · 06-15-2015, 07:10 AM

Yeah what does the EMS indicate? If it says 30 Amp then you need to start there. Reset the actuall breakers on the Generator and the breakers inside. Do NOT trust the idiot breakers to actually trip all the way. Take them to the OFF position and then back to the ON position. When yo are doing this pay close attention to them. One of them make not actually break OFF, which means it is actually tripped but did not go all the way to the tripped position.

motohomo · 06-15-2015, 07:48 AM

The panel blinks every 10 seconds or so, also at that time i can hear the transfer switch click. I should add i lose all electric power, not just the air conditioners. I then can turn the air conditioner switches to off position and all electric power is restored.

grtharris · 06-15-2015, 08:30 AM

motohomo, OK had the same problem on our new coach going to Florida last year. The issue is when you are running both AC units they will get in sync and both will try to start at the same time and overloads the generator the generator drop power and everything goes off, transfer switch drops out and generator power comes back on and after 10 sec transfer switch picks up and both AC try to start and the cycle starts again. Sometime in 2014 WBGO added a start delay to the rear AC unit to prevent both units from starting at the same time. I have lots of information on the delay unit or just run 1 AC when using the generator.
I just send a note to a friend at WBGO asking if this is the same problem I had.

motohomo · 06-15-2015, 08:54 AM

Grtharris. Wow thanks for that info. Makes perfect sense. Did you add the delay unit to yours?

grtharris · 06-15-2015, 09:04 AM

motohomo It was covered under warranty because I had inside info and knew about the added delay unit. Ended up installing it myself but that is a long story.
Lets wait unit I hear back from my friend at WBGO and see if it is a known problem.
Could be a weak start capacitor in one of the units. Do you have a way to measure the current draw starting and running on the AC units?

Dtwallace · 06-15-2015, 09:08 AM

Setting the thermostats at different settings should be a good temporary fix.

JMO
DTW

motohomo · 06-15-2015, 09:36 AM

Grtharris i dont have equipment to measure draw.

motohomo · 06-15-2015, 09:38 AM

Dtwallace, i only run both ac units when it is extremely hot so the thermostat settings wouldnt make a difference because they constantly run in extreme heat

grtharris · 06-15-2015, 03:54 PM

motohomo, my friend at WBGO said both AC units starting at same time could cause the problem. Attached is a pdf of the delay unit. On my unit with Mach 8's and ducted air the delay was installed in the return air duct under the AC unite. I would call Airxel and ask them were to install it on your unit.

motohomo · 06-15-2015, 04:36 PM

Grtharris, thanks for the in depth info. This is my next step in solving this problem.

motohomo · 07-10-2015, 12:33 PM

Update...i took out the transfer swithc and installed the old school plug. Now when i unhook from shore power i need to plug into the receptacle inside the compartment. Problem solved

grtharris · 07-10-2015, 08:02 PM

motohomo, really not a bad idea worst case if power goes off while connected to shore power you will have to go outside and move the power plug. Also you do not have to listen to the transfer switch hum. I assume the generator is handling both AC starting at the same time.

motohomo · 07-11-2015, 04:09 AM

Yes. Now both ac units run together just fine. Honestly i really dont mind the 1 extra step by plugging in. Besides my 1st motorhome was set up like that and it was no big deal.

wa8yxm · 07-11-2015, 06:21 AM

Could the problem be with the Generator?

I know the circuit breakers on my generator seem to be senistive to bumps and such so they have been known to shut off when the generator is not even running... Never seen them turn themselves back on though.. Just off.