Air Conditioning Struggling Using Portable generator

[Bucky1320]

3100 watt generator. Two roof units. Haven't had trouble running one at a time in the past. This weekend neither of them wanted to start on the portable generator. The transfer switch sounded like it was chattering. Not sure if I should be lookng at the transfer switch, the generator or the start up capacitors on the air conditioners. Does replacing the capacitors help them start easier?

[vsheetz]

Have you disabled the economy mode on the generator?

Checked for low voltage coming out of the generator?

[DonDee]

High altitude?

[marcham]

I installed a hard start capacitor on my AC, now it starts and runs in econ mode. (on a Champion 3100w inverter). I'd highly recommend it, it's a lot less wear and tear on the genny.

I'd start with the transfer switch, since it's behaving strangely. Check for loose connections.

[Bucky1320]

Even on not economy mode it was doing it. Not high altitude. How do you check for low voltage during short bursts of high load?
Where do you get the hard start capacitors? I will check for loose connections as well.

[twinboat]

Is the generator booging down when the load is applied ?

If it's running at speed and you switch on the AC, it should hold the speed but get louder as it takes on the load.

If it's slowing down, check for a plugged gas filter or worse, a dirty main jet in the carb.

If there is an open outlet you could measure the voltage there. Get a AC volt meter and stick a probe in each slot of the receptical and read the meter. It should hold 120 volts, even when starting the AC.

If It worked before, both start capacitors probably didn't fail.

[Bucky1320]

Not bogging. You can hear it load the generator though. It has always been marginal when it was cycling. Once it is on, you are good to go. A hard start kit seems like a no brainer. Wish I could find them locally. Pretty cheap through Amazon though. I will check voltage also.
Thank you all for your input!!

[twinboat]

A Kill A Watt meter will give you a idea of what going on, for $25.00.

Are you using the RV plug directly into the generator or possibly a light duty extension cord ?

You should be able to get 25 amps out of a 3100 watt generator.

[Bucky1320]

Originally Posted by twinboat

A Kill A Watt meter will give you a idea of what going on, for $25.00.

Are you using the RV plug directly into the generator or possibly a light duty extension cord ?

You should be able to get 25 amps out of a 3100 watt generator.

Plugging right in, but I don't recall a kill a watt in the 30 amp rv cord style.

[ahicks]

Is it possible that your water heater is turned on (or other large elec. appliance), creating a larger load for the transfer switch?

In other words, have you turned everything possible off prior to hooking up the genny?

[twinboat]

No, but you could dog bone it for a test. One AC should run at less then 20 amps.

Or plug it in, inside and watch the volts, when the AC kicks on.

I tested mine and it ran at 15 amps.

[mn.roadking]

I would say a 3100 watt generator would be borderline for starting an A/C unit.

[Bucky1320]

No electric element in water heater.

Yesterday afternoon we ordered two of the hard start capacitors from Amazon. I come home from work today......here! A half hour later both were installed, and tested. I can leave the generator on economy mode just as was said above. Thanks for the great tip!

[WSRG]

This may sound stupid...but I have fixed a problem like this by sanding the contacts on the plug that you plug into the gen.

Bill