I know the ideal scenario would be to shut off the A/C at the thermostat prior to turning off the generator, but in practice I'm sometimes pulling into a gas station with the generator and air running and just kill the generator from the drivers seat. Is this doing any damage to the generator or air conditioner?It's an Onan 4k Microquiet, and a Coleman Mach 15 ducted A/C.Similarly on the other side of it, I restart the generator from the drivers seat after leaving the pump and the A/C comes back on. This seems less bad to me, as there seems to be some delay between the generator starting and 120v being supplied, I suspect there's some electronics in the generator that is waiting to supply power until it's up and stable. But that's just a guess. Am I right?Just trying to determine if it's worth the extra effort to get up and shut down the air conditioning before killing the generator. :B

I ALWAYS turn the acs off with the thermostat. When you start the genset your ATS delays switching over until the genset is stable. I leave my genset running when fueling just like the millions of reefer trucks do.

camperdave wrote:Just trying to determine if it's worth the extra effort to get up and shut down the air conditioning before killing the generator. :BYES. Going both ways.Shutting OFF.....the gen is very HOT from running.Immediately chopping the air flow over the engine might make it WAY hotter than it is supposed to be.It is always recommended that you start the gen a minute or two before applying a heavy load......especially when cold.You will be better off in the long run by doing it "right".

No ATS, my 30a cord is plugged directly into the generator.

camperdave,Don't be surprised when your generator goes belly up. It needs a cool down after running at close to full load with the air conditioner running. Read the owner's manual. Shutting it off when it's as hot as it can be is extremely bad practice. Onan recommends a 3 to 5 minute cool down:Onan MicroLite 4000 Owner's Manual wrote:STOPPING1. Turn off air conditioners and large electrical loads before stopping to allow the genset time to cool down. 2. Let the genset run three to five minutes. Failure to let the genset cool down can cause engine run-on or backfire. 3. Push the Star/Stop switch to the Stop position.You've been getting away with it so far but don't expect your luck to last forever.

Big Katuna wrote: When you start the genset your ATS delays switching over until the genset is stable. I leave my genset running when fueling just like the millions of reefer trucks do.Not everybody HAS an automatic transfer switch.And the generator on a refer semi is at least 20 feet from the fuel tanks, which take diesel fuel, which is nowhere near as volatile as gasoline.

shutting down generator with air conditioner running

29 Replies

RedRollingRoadb
Explorer
Aug 22, 2019
2oldman wrote:
Not a great idea. You'd be better off to leave everything running. Find a pump away from people who will have you arrested for it.

Then every state is different. I'm in Oregon, no self-serve, engine off. But pulled in one time and for some reason I forgot to kill A/C and generator. Attendant asked it that was a generator running. That was allowed and pumped away.
MEXICOWANDERER
Explorer
Aug 22, 2019
Read up on...

The effects of AC GENERATOR FIELD FORCING

Then check the price of a replacement voltage regulator.

It will have you practically leaping from your seat to shut off the generator AFTER all loads are disconnected.
2oldman
Explorer II
Aug 22, 2019
Not a great idea. You'd be better off to leave everything running. Find a pump away from people who will have you arrested for it.
Johno02
Explorer
Aug 22, 2019
Mine will pop the circuit breaker every time I do that. So I shut everything off, then stop generator.
Sam_Spade
Explorer
Aug 22, 2019
Big Katuna wrote:
When you start the genset your ATS delays switching over until the genset is stable.

I leave my genset running when fueling just like the millions of reefer trucks do.

Not everybody HAS an automatic transfer switch.

And the generator on a refer semi is at least 20 feet from the fuel tanks, which take diesel fuel, which is nowhere near as volatile as gasoline.
DFord
Explorer
Aug 22, 2019
camperdave,
Don't be surprised when your generator goes belly up. It needs a cool down after running at close to full load with the air conditioner running. Read the owner's manual. Shutting it off when it's as hot as it can be is extremely bad practice. Onan recommends a 3 to 5 minute cool down:
Onan MicroLite 4000 Owner's Manual wrote:
STOPPING
1. Turn off air conditioners and large electrical loads before stopping to allow the genset time to cool down.
2. Let the genset run three to five minutes. Failure to let the genset cool down can cause engine run-on or backfire.
3. Push the Star/Stop switch to the Stop position.

You've been getting away with it so far but don't expect your luck to last forever.
camperdave
Explorer
Aug 22, 2019
No ATS, my 30a cord is plugged directly into the generator.
Sam_Spade
Explorer
Aug 22, 2019
camperdave wrote:

Just trying to determine if it's worth the extra effort to get up and shut down the air conditioning before killing the generator. :B

YES. Going both ways.

Shutting OFF.....the gen is very HOT from running.
Immediately chopping the air flow over the engine might make it WAY hotter than it is supposed to be.

It is always recommended that you start the gen a minute or two before applying a heavy load......especially when cold.

You will be better off in the long run by doing it "right".
Big_Katuna
Explorer II
Aug 22, 2019
I ALWAYS turn the acs off with the thermostat. When you start the genset your ATS delays switching over until the genset is stable.

I leave my genset running when fueling just like the millions of reefer trucks do.

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shutting down generator with air conditioner running

29 Replies

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