Generator Dies When Air Conditioner Is Turned On

[lbrunning]

If its the load killing the generator before the breaker trips something is wrong with that engine.

[Jlklingejr]

So normally when you overload a generator the circuit breaker trips without the generator shutting off?


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[AquaMan]

Does the generator have any type of "eco" setting? Not sure on built-in generators, but on my portable, it will run my A/C on full power, but not on eco. If I gradually load up the generator, it will run most everything just fine. It just won't take that first inital draw from the A/C all at once.

[RamblerGuy]

Originally Posted by lbrunning

If its the load killing the generator before the breaker trips something is wrong with that engine.

I disagree. The starting load of the A/C is instantaneous and is several amps more than the running load. Breakers take a little time to trip out. They have to be this way to permit starting loads. The generator doesn't have the excess capacity that a shore line can supply so starting loads affect it more.

[lbrunning]

No the onan generator does not have an eco setting. For what it is worth here is how I run my sunseeker refrigerator on auto water heater on propane and ac on most of the time never had a problem with generator stopping or breaker tripping. I can run ac and microwave or hot plate or hair dryer and not trip breaker. I currently have 1027 hours on my generator trouble free. A couple other things to check is your fuel tank over 1/4 full and did you check oil level in generator .

[bclemens]

What size is the A/C??? 13.5 or 15k with heat pump?

[howzball]

I don't know if there could be any special safeties on the Onan that doesn't like the wiring for your A/C?
I'm saying, *maybe* there is a wiring fault to your A/C that the shore power just doesn't worry about but the generator is sensing a problem and killing itself as a precaution.... IF this is even possible.

I have on one occasion had the Onan to shutdown as soon as we turned the A/C on but, I just restarted it and tried it again without any issue.
Mine was just a cold engine issue.

Again, *If* there are any safeties built into these generators then I would suspect that.

[Jlklingejr]

My A/C unit is a 13.5.


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[Jlklingejr]

I let my generator run for an hour with no load. Then I turned on the A/C and the A/C started right up. I am going to let it run for a couple of hours. Should I do this every time or should I take it in on warranty? I used to be able to start the A/C right away with no issues. Also I am at my 20 hour first oil change so am going to change the oil after it runs for 2 hours on the A/C.


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[MrJoe]

I've tripped the generator breaker a couple times. I keep forgetting the electric water heater is on when starting the microwave with my 15K Ac/Heat pump running. Never had the generator stop. Does the panel flash a code?

[Jlklingejr]

After the oil change. I started the generator with no load and it died in 10 minutes. I used onamax and put in 1.6 quarts. I checked the oil level and it is perfect.

I restarted the generator and let it run for 5 min then I started the A/C and it died again (A/C on 70 degrees).

I restarted the generator after it died and let it run for 15 minutes (it was still warm since I ran it for 2 hours before the oil change) then started the A/C but I started the A/C at 80 degrees (so it would not kick on). The I decreased the temperature by 1 until the A/C turned on (75 degrees) and it worked again.

What the heck is going on?

Thanks for your help guys,

Jeff


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[lbrunning]

At this point with 20 hrs on it I would get it to an onan dealer for warranty work. There is no way this generator should not do what you want it to.

[Jlklingejr]

I'm thinking the same.

Thanks.

I will reply when warranty work reveals the cause of this issue.


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[wesslvm]

I'll bet you suffer from a failing fuel pump.


2014 Sunseeker 3050S

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[davegood]

Make sure you have sufficient gas. The generator won't work if the tank is near empty.
I warm up the generator just 5 minutes, then turn on the ac. Never had a problem.
Test using microwave only (no fans, fridge, water pump, water heater, etc).
If the generator is under warranty, call the dealer service dept and ask for advice. Bottom line is you don't want to spend any money and the thing should work correctly.

[trdutch]

My brand new gen ran rough and stalled the first time I put air on
This unit sat on the lot for a year and the carberator gum up easily
I ran a batch or sea foam through the fuel system and ran the gen un loaded for a few hours and she purrs like a kitten
With a load

[mud yapster]

Make sure your unit is level when running the generator I had a buddy's generator cutting off and not wanting to run and he was trying to run it at the baseball game parking lot and his unit was way out of level. We leveled his RV and it ran perfect after that. Just a thought to try if your unit is way out of level.

[Jlklingejr]

Thanks for all of the input guys. I am taking it in on Monday. I never mentioned it gives me a fault code 36. I did everything in the manual for that fault code.

I'll let you guys know what Cummins finds on Monday.


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[mud yapster]

Thanks, keep us informed I may have the same problem one day. Good luck

[Jlklingejr]

UPDATE:

I just got back from a Cummins Onan Service center. The generator checked out 100% fine. He hooked up to a load bank and maxed it out at 4000kW and the genset worked great. He even overloaded it to check the 30A and it worked. I told him of the issue I was having that it would cut off when the AC is turned on (with no other loads). He told me he ran the AC just fine.

I went with the service tech to the RV and started the generator. I let it run for 10 minutes (to let the AC decompress) and tried the AC and it died. We tried a couple more times and it ended up working again. I ran the gen/AC for the 2 hour ride home to exercise the generator.

I am guessing it is the AC unit. I have an appointment with Dometic today at 3pm. I'll let you know what they say. I am fearful they will say the AC is fine then I will be back to square one since the problem may be intermittent.

So frustrating......