Stalling Genset

[Bob RV]

We were on our way back from Daytona last week we stopped over in a Walmart for the night and we were running the heat pumps outside temp 32f, During the night I heard the pumps try to kick on making the genset stall has anyone had this problem? And any ideas why this would happen?

[DriVer]

Originally posted by Bob RV:
.... running the heat pumps outside temp 32f, During the night I heard the pumps try to kick on making the genset stall has anyone had this problem? ....

I might initially offer that your heat pumps are not designed to operate at temperatures anywhere near 32° F and it might be possible that they were calling for too many amps which stalled the generator.

Just a guess at this point.

One thing you want to keep in mind as well if you are a little low on oil the generator won't even start and running low on oil will cause the generator to stall.

[MrTransistor]

Hi Bob,

Normally, the heat pump will not work if the temperature goes below say 35 degrees. It has a thermistor that is used to sense the temperature of the evaporator to prevent frost from building up and blocking the fins. The unit (unfortunately) does not have a reversing cycle, like home units have, that melts the frost from the fins.

When the unit senses that the temperature is too low, it shuts down the compressors. If the thermistor then senses a rise in temperature and the unit tries to restart the compressors under pressure, then the compressors will be stalled and draw way too much current for too long (a few seconds) and cause the generator to stall. If you were connected to a 30 Amp. pedestal, it would probably trip the breaker.

You can modify the circuit to reduce the temperature at which the unit shuts down but for all practical purposes, when the temperature is expected to go below about 40 degrees (it varies per unit) then I would switch to propane heating or use portable electric heaters.

[Bob RV]

Driver, Thanks for the input the oil level was good I check it religiously, What is the coldest I should run them? We also had the genset shut down once when the air was on last year but I didn't think nothing of it.

[DriVer]

Originally posted by Bob RV:
.... What is the coldest I should run them?

Bob RV, I won't try to run my heat pumps below 40 degrees. The Winnebago thermostat is supposed to automatically switch over to "furnace" when the heat pumps can't keep up. I have been meeting some difficulty with that happening consistantly.

Knowing the temps, I will switch over to furnace.

[AFChap]

We've never had our heat pump or ac stall the generator, or trip a breaker (nearly 1000 genny hrs in almost 5 yrs) on startup. If too cold for the heat pumps (anywhere from 35-40 depending on humidity) they have seamlessly defaulted to the main LP furnace. If the overnight temp is forecast to be below 38 or so I normally just turn the thermostat to gas heat before going to bed. It sounds to me like there may be another issue involved/something not working right.

That said, we would rarely if ever leave the generator running all night for heat (and our generator is at the other end of the coach, not under the bedroom as I presume it is on your Adventurer). If we did, we definitely would have an exhaust extension on the genny to get the exhaust above the motorhome. With the refrigerator running on LP, your batteries should easily last overnight, running the furnace blowers as needed -- and the cost of LP used would most likely be much less than the fuel cost to run the generator all that time!

[TXiceman]

have you tried to run the heat pumps on shore power, provide it is warm enough out side?

It the heat pump compressor(s) locked up, it should drop out by tripping the breaker and not stall the generator.


If the heat pumps operate, then you need to get the generator set checked.
Ken

[NeilV]

That could be a symptom of the starter caps on one of the compressors going. The failure of the compressor to start can overload one side of the generators fields and stall it out.

Technically the breaker should trip first however things don't always work as they should and if it is the compressor on the 30 amp side of the generator with the rest of the house then it is more likely to happen then with the compressor that is stand alone on the 20 amp side.

[hamguy]

We were dry camping in the desert a couple weeks ago. Woke up one morning to an outside temp of 32.7 and inside of 42.4.

I fired up the gene and the basement furnace. The first heatpump fired as is should and soon, the second did also. However, the gas unit also came on for a while.

[Izzyblueye]

Perfectly normal sequence of procedures. You are at the bottom of the range for your heat pump.

[Bob and Vicki]

Our generator stalled once. It ran out of fuel. The fuel pickup for the generator does not go as far into the tank as the engine pickup does. I think the tank was at the 3/4 mark on the gauge. We now keep the fuel tank above 1/2.

[Bill Gotthelf]

Another thing to check is the generator fuel filter. When the generator is put under a load it uses more fuel and if the filter is marginal it could starve the engine for fuel.

[Bob RV]

Bill,
Thanks for the input,As of yesterday I ran the generator for about a half hour and than it stalled I restarted it and it ran for another 10 min again stalling. After changing the oil in it I started the genset put a load on it and it ran for about 45 min as soon as I took the load off it stalled, I'm bringing it in to the shop to have it checked out. The biggest problem I have with this whole thing is that it only has 239 hrs on it, I called onan and they were NO help at all in fact they were very rude about the whole thing.At least other component venders will work with you whene you have problems or at least try to help Onan didnt want anything to do with it. Thanks for listening,