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Stluvisi 05-15-2021 01:37 PM

A/C will not run on generator
2 Attachment(s)
Ac worked for 3 days on shore power then disconnected. Have tried several fixes... reset inverter, generator and circuit breakers. Same info displays on Power Control System. Any suggestions would be appreciated.

kekker 05-15-2021 02:22 PM

I HAD A 3500 WATT Generator that would Not run My AC on My new Hideout. I bought a 9750 Watt and No more problems.

twinboat 05-15-2021 02:39 PM

I have read your post 6 times.

Do you want it to run on generator or shore power ?

Did you disconnect from shore power, or did shore power shut down ?

The inverter is not involved in your ACs.

Winepress 05-15-2021 02:40 PM

Check breakers. Verify generator is supplying voltage.

LETMGROW 05-15-2021 02:47 PM

I'm with Twinboat here. If you plug back into shore power will the A.C. run?
Do you have more than one A.C.?
Do you have an automatic transfer switch.
Does your generator run? What make, model and wattage is your generator?
Some information about what you have for an RV would be helpful.
We can't help much if we can't understand your question.

twinboat 05-15-2021 03:18 PM

Here's a thought, did you switch off the house battery disconnect switch ?

Doing so may have turned off the thermostats.

C.Martin 05-15-2021 03:57 PM

I think the disconnect also shuts down power to the PCS panel, which appears illuminated.

If you turned the generator ON while connected to shore power...there is a likelihood, if the Transfer switch Mechanical Interlock isn't aligned properly, the breakers on the generator itself will trip. Try disconnecting from shore power, turning off Climate Control, starting the generator, let it warm up, double check the breakers on the generator itself...then look at the PCS panel to see if it recognized the generator voltages...then reinstate the climate control.

Stluvisi 05-15-2021 04:25 PM

Sorry I wasn’t clear, rookie mistake! We had disconnected from shore power , driving the coach & decided to turn on zone 1 AC so engaged generator but ac didn’t come on . Tried the other two zones , those did not turn on either. House batteries were on .It’s an Onan 8000 2015 Newmar Ventana 4369.
BTW, this is the DW so please forgive my lack of details while trying to assist my DH!! Thanks all!!

C.Martin 05-15-2021 07:36 PM

Did you get an E7 fault displayed on the CCC climate control?

The Generator, with PCS will shed all 6 loads it controls...depending on software revision for a warmup period...your climate control center also has a time delay to prevent the compressor from doing a restart while the pressure is still hiigh. If you get an E7 fault...turning the climate control OFF, waiting for the generator to warmup, and then turning the thermostat back on should get it going. But it always helps to follow the trail...and find out where the issue is... Generator breaker, transfer switch, surge protector, PCS system, load center, thermostat... helps to have an idea how the electricity gets routed from power supply to final load...and where the things you control are along that pathway...and what visual indicators you might see to alert you to a particular fault...

New2road 05-16-2021 01:45 AM

look at the breakers at the genset, likely open. had this happen on our CS. techs had opened breakers to work on system.

Semituff810 05-16-2021 05:59 AM

Not sure what coach you have- but on our DS there is a breaker switch under the hood, right on top of the generator We had the same problem after having our coach serviced. AC ran on shore power but not on generator. Flipped the breaker switch and all was well. Good luck.

Stluvisi 05-16-2021 07:34 AM

Thanks all! Interesting, we just had our generator service , so could be the issue.

wolfe10 05-16-2021 07:36 AM

Turn the two breakers on the generator itself OFF and back ON.

Easy for a tripped breaker to look like it is ON-- just a little way toward OFF, but not enough to be obvious.

Stluvisi 05-16-2021 11:54 AM

wolfe10 and new2road seem to refer to more than one breaker on the generator. I can only find one, is there one less visible?

TJ 05-16-2021 12:30 PM

On the Newmar coaches with 8K Onan, there is just one breaker set on the generator. It is common for techs to turn the breaker when servicing the generator, and nearly as common for them to forget to turn it back on. ;)


wolfe10 05-16-2021 12:35 PM


Originally Posted by TJ (Post 5753456)
On the Newmar coaches with 8K Onan, there is just one breaker set on the generator. It is common for techs to turn the breaker when servicing the generator, and nearly as common for them to forget to turn it back on. ;)


Yes, one breaker SET (two breakers pinned together).

Stluvisi 05-16-2021 02:59 PM

what does oa mean on the end of the stat line on pcs read out

twinboat 05-16-2021 03:41 PM


Originally Posted by Stluvisi (Post 5753655)
what does oa mean on the end of the stat line on pcs read out

" 0 ", ( zero ) Amps. There is power but nothing is using it.

Check the controls for the ACs.

C.Martin 05-17-2021 05:01 AM

Actually, those 0 A readings are misleading.

It isn’t how many Amps that particular circuit is drawing at that moment... It is a memory folder for how many Amps the unit was drawing when a Load Shed occurs. It only fills in when the total draw on a Leg or combined draw ( if less than 50A was available ) was reached and one or more of the 6 selected items capable of being shed, were actually shed. The PCS needs this reading to compute when sufficient amp overhead is available for reinstating that load again.

Example... you were hooked up to a 30A shore power outlet...and you had one air conditioner running, two water heater AC elements, the washer as runningg...and your total current draw was near 30A. Then you turned on the dryer to finish drying a load you had in the dryer...and the PCS decided to shed both of the Hot water elements to accommodate you. There would be an A reading next to those two slots. I don’t know what they would have been...but for the sake of argument...let’s say 5A each... So the PCS is trying to stay below will look at the 5A overhead requirement, and subtract that from 30A. When it sees the total is below 25A, it will reinstate the first...again it will wait until the total is below 25A again to reinstate the last one. The only place the current Amperage is displayed there is the first page with L1 and L2 displayed...

okcnewbie 05-19-2021 07:54 AM

Your last sentence sounds like the compressor is on but the blower motor isn't.
Are you able to turn the fan on by itself?

chefred112 05-21-2021 03:31 PM

When I 1st got my new to me 2002 MADP I couldn't figure out how to run the AC's consistently...I would keep fiddling with the thermostat to try and get it to work. Another user said patience is key.. Finally figured out if I want to run the ac(s) while driving I would first turn on the the generator..I watched my control panel until I saw the bulk/float charge light turn on at which time I would turn the thermostat on and run the ac. I would leave zone 2 off and close the pocket door so that only the front area would need the ac where my passengers are sitting at. I don't have digital readouts like the newer models so I rely on the indicator lights.

Stluvisi 05-22-2021 09:22 AM

Thanks all for the advice and suggestions. We think its the capacitor since on front AC since the other two work. Have ordered one and hope this solves the issue.
Will keep you all updated!
Thanks again!

vawinger 05-24-2021 01:39 PM

Same thing just happened to me. Picked up new (to me) Ventana from dealer on Saturday. It had been hooked to shore power. On the way home, getting hot, fired up the generator. At a stop light, I stood up and tried to turn on the A/C. I didn't check that they actually came on, but by the time I got home it was obvious that they didn't.

Several hours later after working to load all the stuff in the coach with no A/C, I started looking at it again. Fired up the generator, and A/C won't come on. Then I noticed a power or on/off button on the top left of the panel for each zone. It was off. Turned it on, and voila! Not sure why it was off, but there you have it.

Hope this helps!

Turbojack 05-24-2021 02:21 PM

So when you plug back into shore power the back two ac run but now the front will not run?

Stluvisi 06-02-2021 02:32 PM

Problem was the capacitator, replaced it front AC unit working.
Thanks for the suggestions.

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