New Trailer

[Cacciato2006]

Hello All, our new trailer was delivered today. Been running a Champion 3,500 on our other trailer. Before I bought our new RV I took the generator in town and plugged it into another 2019 Montana identical to the one we purchased and it ran the trailer and one AC perfectly. Turn the AC on and off several times. Only difference between that trailer and the one we purchased is we had the generator prep and the ATS installed. I made sure both air conditioners were off and powered up the generator. Fridge comes on, house batteries are charging etc. When I turn on either AC the ATS starts switching back and forth. You can hear a loud clunk in the stair area. Anyone have any ideas what might be going on?
Thanks,
David

[Mudchief]

Congratulations on your new Montana and hope you have many happy times in it. Welcome and enjoy the forum.

[Dhardy]

The clunk in your stair area is the transfer switch. This could be caused by high load on generator causing the voltage to dip too low. Do you have a 3500 watt inverter generator or just a standard generator?

[Cacciato2006]

It’s the champion duel fuel inverter generator. To be fair I am running it one propane and I know I’m only getting 2,950 to 3,000 watts out of it. I’ve tried it with both eco on and off. If every breaker is off except the rear AC it will turn on and run fine in either mode. If I turn on the central vacuum breaker only (not running the vacuum) and try again the ATS will start switching. You can shut off the vacuum breaker and repeat with any other breaker in the RV and it will do the same thing. I’ve been running this generator on a 30 amp trailer for several years using at 15k btu Coleman AC. I can think of one time it tripped the break on the generator. Scratching my head at this point. Are you thinking if the voltage drops to low the ATS is looking for another source of power?

[daveinaz]

Originally Posted by Cacciato2006

Are you thinking if the voltage drops to low the ATS is looking for another source of power?

That would be my guess.

[Cacciato2006]

As popular as the Champion inverter generator is I would think someone would have had this problem before. When I was in a park in Tyler Tx my neighbor had is Champion going running his 5th wheel AC. Only difference between mine and his was the generator prep with the transfer switch. Anyone know if it can be disabled?

[jetskier]

Are you powering it through the gen prep wiring or just an adapter on the main shore power cord?

You probably should check the voltage with the AC running and then adding another circuit. If you can't turn on a circuit with an outlet and probe there, you can remove the main panel cover to the breakers and probe directly on the main 50A breaker. If you are willing, the ATS is usually accessed in the front compartment behind the back panel under the stairs. You could check the voltage there with various items running. It is possible you may have a bad ATS or it doesn't like your generator.

If they are still putting the Dometic Blizzard NXT 15k ACs in the new trailers, they draw 1767W.

For comparison, I can run all three ACs with my 5500W propane Onan with all other breakers off and starting them one at a time. The ATS doesn't flutter at all. When I checked the voltage with all three going, it was 113V.