2014 RW 400 - Can't run 2 ACs while on Gen

6.7LMegaCab

Well-known member
Need a little troubleshooting assistance. Out camping and I can't get both air conditioners to run while on the generator. As soon as I turn one off, the other starts working again. When I attempt to turn both on, A/C power is cut off and it sounds like what I believe is the transfer switch starts rattling or something.

No breakers are tripping on the main panel inside the coach and the 2x 30 Amp breakers on the generator are not tripping either.

Once I turn one AC unit off, A/C power of restored.

Can anyone shed light on what's going on? As soon as my boys and I are done camping, we'll be home for about a day and a half and the rest of the fam is loading up to head out on a 7 day trip (pending both AC units will run on gen). Fortunately, most nights will be at an RV park, but we will be boondocking a couple nights as well.

Any help is greatly appreciated!

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rwdennis

Active Member
what size generator ? i have a 44 ft road warrior with 3 ac units , i can run 2 on my 5500 onan genny , i did trip the breakers once , i just let one run for a few minutes before starting the other one , you may look into a device called a easystart if you continue to have problems , good luck ..
 

LBR

Well-known member
Need a little troubleshooting assistance. Out camping and I can't get both air conditioners to run while on the generator. As soon as I turn one off, the other starts working again. When I attempt to turn both on, A/C power is cut off and it sounds like what I believe is the transfer switch starts rattling or something.

No breakers are tripping on the main panel inside the coach and the 2x 30 Amp breakers on the generator are not tripping either.

Once I turn one AC unit off, A/C power of restored.

Can anyone shed light on what's going on? As soon as my boys and I are done camping, we'll be home for about a day and a half and the rest of the fam is loading up to head out on a 7 day trip (pending both AC units will run on gen). Fortunately, most nights will be at an RV park, but we will be boondocking a couple nights as well.

Any help is greatly appreciated!

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Make sure the 120V side of hot water heater is not used...only on propane

Am doubting you have a residential refrigerator, but if so, shut it off at breaker panel.

Shut the converter breaker off at the breaker panel.

Now while making sure no other heavy 120V loads are be used, try the 2 ACs at same time and stagger their start times.
 

6.7LMegaCab

Well-known member
The generator is an onan 5500. We were able to use both at the beginning of the month. Nothing had changed since then.

We don't have a residential fridge and the heater was off or on propane. The only other item running was the TV. All of which we were able to run at the same time.

No breakers are tripping.

Is that the transfer switch that would be making that rattling noise when both units are attempting to start?

I'll take a look at it this afternoon. Gonna go try to lure in some fish with the boys.

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Last edited:

danemayer

Well-known member
Take a look at the arrangement of circuit breakers in your main panel. The 2 air conditioners should be on different power legs (unless you have 3 units, in which case 2 will be on the same power leg).

Starting with the two linked 50 amp breakers, as you go to the right, the breakers alternate - leg 1, leg 2, leg 1, leg 2.

Chatter is likely from the transfer switch contactors. Could be weak, or could be voltage dropping on leg 1. If L1 output from the generator (or shore power) drops below 105V, the contactors will drop. If your generator is putting out low voltage, that could be the cause of the chatter.

If you have a volt meter, you can check the voltage in various outlets inside the RV.

You could have loose wires in the transfer switch, or junction box, or back side of the circuit breaker panel.

Our Electrical User Guide has drawings and pictures that may be of help.
 

Robsterling

Member
The noise you are hearing (sounds like rapid clicking) is your transfer switch. For whatever reason, your generator is refusing to carry the 30 amp load required to run 2 AC’s.
You may also have a bad transfer switch.
When you switched to generator are you turning both ac’s on separately? What else is running?


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carl.swoyer

Well-known member
I set my AC's two degrees apart. This way they come on at different times.

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6.7LMegaCab

Well-known member
Take a look at the arrangement of circuit breakers in your main panel. The 2 air conditioners should be on different power legs (unless you have 3 units, in which case 2 will be on the same power leg).

Starting with the two linked 50 amp breakers, as you go to the right, the breakers alternate - leg 1, leg 2, leg 1, leg 2.

Chatter is likely from the transfer switch contactors. Could be weak, or could be voltage dropping on leg 1. If L1 output from the generator (or shore power) drops below 105V, the contactors will drop. If your generator is putting out low voltage, that could be the cause of the chatter.

If you have a volt meter, you can check the voltage in various outlets inside the RV.

You could have loose wires in the transfer switch, or junction box, or back side of the circuit breaker panel.

Our Electrical User Guide has drawings and pictures that may be of help.
Thank you for the info. Unfortunately I haven't had a chance to look into it. Before we departed the house for part two of travels with everyone, I didn't park the trailer close to the RV box at the house, so I had run the generator to cool the RV down. My wife tried running both ACs and it kept tripping the bottom 30 A breaker on the generator, so that tells me they aren't on separate legs. Up until yesterday evening we've been staying at RV parks along the way and are now dry camping through tonight. Last night were had the generator running with both ACs, 2 TVs, fridge transferred to A/C power, then I noticed the microwave running. My daughter put in a bag of popcorn. Nothing tripped, surprisingly. So it's definitely random. We'll be home in a few days, so I may have a chance to look into everything.
The noise you are hearing (sounds like rapid clicking) is your transfer switch. For whatever reason, your generator is refusing to carry the 30 amp load required to run 2 AC’s.
You may also have a bad transfer switch.
When you switched to generator are you turning both ac’s on separately? What else is running?


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Thank you for the info. Everything now seems to be working, but I'll look into it when we get home in a few days, unless it starts acting up, in which case I'll get out the multimeter. I may have to move one of the ACs to the other leg on the generator.

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avvidclif

Well-known member
On mine I have equalized the load on the legs and when both AC's are on the fridge and water heater are on propane. If for a day or so the converter is turned off also (100AH AGM). Making a chart of what is hooked where will let you know what you can run with both AC's on and if need be one can be shut down temporarily to run the microwave or other high current use.
 
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