Cummins QG 4000 kicking off when AC is turned on.

[5 speed-FRF]

So new to me RV but 2015 Vegas. Gennie ran fine at the dealer 430 hours. It will run the fan but once you turn it to AC it kicks off. I changed the oil and it runs smooth. Didnt overfill, just over the add line. Clean air filter. Gas tank at 3/4s. I read about the codes but when I tried it again with AC on it threw no codes. Any ideas what to check? Seems like its overloading maybe. Starts right up.

 

[ducksface]

To know if it's an air conditioner problem;
Load the generator with the microwave and a space heater or two.

 

[5 speed-FRF]

Sure I can do that I will say on shore power the AC is really cold and had the coach down to 70 and it was 85 outside so ai think the AC is not the problem. Thats on a 20amp circuit that tripped when I had the fridge on too ( known issue even with my other camper, need a dedicated 30A circuit.

 

[16ACE27]

Sure I can do that I will say on shore power the AC is really cold and had the coach down to 70 and it was 85 outside so ai think the AC is not the problem. Thats on a 20amp circuit that tripped when I had the fridge on too ( known issue even with my other camper, need a dedicated 30A circuit.

Even 20 amp SP is much more capable of handling the starting current of a problem compressor than the generator is.
Between a poor starting capacitor and slow reacting governor the generator will easily be thrown into an under speed death spiral.

 

[5 speed-FRF]

Sure understood and I should clarify: when the AC kicks on its running for a short period, a couple of minutes maybe and then is shuts down so it feels like its not that compressor amp requirement thats causing it but then its shutting down maybe due to heat. I will try all suggested and report back

 

[16ACE27]

once you turn it to AC it kicks off.

"Kicks off" can mean different things. I assume you mean shuts off?
Is "it" the Air Conditioner or the generator?

For any real help you need to be specific on the symptoms.

 

[5 speed-FRF]

So i tried generator microwave refrig and heater. Ran fine. Now I tried putting the ac on and its running. 3 minutes in no problem. But Ambient temp is a low 71. Vs 86 in the sun Dont know

 

[ducksface]

Your ac itself does not know ambient temps BY DESIGN.

 

[ducksface]

A story;
Early Durango suv had a cutoff in the ac that if ambient hit 110 the damn ac quit.
My friends summer trips to Havasu always ensured the ac would quit at about the top of the Cajon Pass then start working again after the Havasu trip.
It took chrysler a year to admit their stupidity.
Pulled a wire and all was fine.

 

[5 speed-FRF]

When I transfered to shore power the same day, it worked fine. Its cold. I think there was less load on the generator for some reason. Ill try again in the hot afternoon and see what happens but tonight the gen was running the air no problem. I did find an outlet that wasnt working while on the gen near rhe sink and none of the overhead lights were working which was odd. No breakers flipped on the panel so not sure what thats about.

 

[16ACE27]

When I transfered to shore power the same day, it worked fine. Its cold. I think there was less load on the generator for some reason. Ill try again in the hot afternoon and see what happens but tonight the gen was running the air no problem. I did find an outlet that wasnt working while on the gen near rhe sink and none of the overhead lights were working which was odd. No breakers flipped on the panel so not sure what thats about.

Breakers don't power the overhead lights. They are DC powered lights supplied by fuses and switches.

 

[5 speed-FRF]

Ah gotcha makes sense. Ill have to check that tomorrow

 

[OldWEB]

If your house battery voltage was down, then maybe the converter was drawing a few more amps and with the a/c load was too much?

 

[PS89]

I did find an outlet that wasnt working while on the gen near rhe sink

The outlets don't know or care if you are on generator or shore power. They should behave the same regardless. Remember that outlets near wet locations are REQUIRED to have GFCI protection. Thor tends to put a (cheap and unreliable) GFCI receptacle in the bathroom and then daisy chains that circuit to the kitchen and outdoors (if equipped).

 

[5 speed-FRF]

Thats right thank you for that! I will ck it out tonight and see if the fuses are the issue.

 

[5 speed-FRF]

If your house battery voltage was down, then maybe the converter was drawing a few more amps and with the a/c load was too much?

The batteries are new but I will break out the multimeter and check them.

 

[LaProvi]

So new to me RV but 2015 Vegas. Gennie ran fine at the dealer 430 hours. It will run the fan but once you turn it to AC it kicks off. I changed the oil and it runs smooth. Didnt overfill, just over the add line. Clean air filter. Gas tank at 3/4s. I read about the codes but when I tried it again with AC on it threw no codes. Any ideas what to check? Seems like its overloading maybe. Starts right up.

Make sure the Gen is not overfilled with oil. The ac start capacitor maybe it's faulty.

 

[5 speed-FRF]

Hi and thanks. So the main overheads dint work. The one over the couch does. I checked all the fuses and all looked good. I replaced the one marked lights for kicks but they still dont work. I see the my are leds so doubt its a bulb issue