Air Conditioner and Generator sizing

[craig72]

Hey gang,
Does anyone know if you can successfully run a 4-ton unit with the 10kW/9kW units?
I am looking to purchase a generator and trying to decide if its worth the extra money to go bigger just to have the ability to run the A/C. I can all of my essentials otherwise by simply using a 7kW/6kW unit.
Thanks!
Craig

[M Miller]

You will not be able to run a 4 ton AC with a 9 KW unit. If your AC is also a heat pump don't forget you will also need to power those auxillary heat coils too (if you have them) unless you wire a relay to cut them off when under generator power. They are most likely powered by the 240 volt that also powers the air handler. I'm not sure how many amps they use but my air handler is on a 60 amp breaker. I have a 6 KW (NG) generator with a 16 ckt panel and didn't power the heat or AC. My hot water is gas as well as my other furnace and no well pump so no heavy use circuits in my 16 ckt panel.

[craig72]

I have a gas furnace, water heater, and cooktop. My HVAC blower is on a standard 15A 120V circuit, so no problem there. I was just curious if the 9kW had enough 'umph' for a 4-ton.

[M Miller]

No. On your outside unit you will find a tag that will list among other things the LRA which is the Locked Rotor Amps. This is the max amps it will take to start your compressor. This figure on a 4 ton unit will be MUCH higher then the 37.5 amps (@240v) a 9KW generator will produce.

[craig72]

You answered my question.
Thanks for the reply!