AC not working with generator

Does the other 120 volt systems work?
Does your rig have a transfer switch or do you have to plug the shore power cord into a receptacle in the shore power cord access?
Edit:
Reread your post. Check circuit breakers on genset?

Do you mean air conditioner by AC, or all the alternating current electrical system? Is this a built-in generator or an external portable generator?

If it's all the power, as enblethen said, check the circuit breaker on the generator--true for both built-in and portable generators. Don't rely on a visual check, but flip the breaker off and on (if it's a lever kind) or otherwise try to reset it. Some look to be engaged even after they trip.

If it's all the power and it's a portable generator, possibly you have an EMS installed and it sees the unbonded generator as an open ground and won't connect the power.

If it's just the air conditioner, does it try to start? If so possibly your generator just isn't supplying enough power to get it to start.

enblethen wrote:
Check circuit breakers on genset?

This. The generator has it's own breakers and they often will trip before the main ones (lower amp rating).

Yes, need more information:

ATS or manually plug in generator?

Breakers on generator turned OFF and back ON?

Other than the roof A/C, what other 120 VAC appliances/outlets do not work on generator?

Looks like breaker on generator was tripped. We did check it the first time, so don't know how to explain it. Switching the breaker back and fourth again got the A/C working. Thank you all.

Txnese,

Thank you for coming back and closing the loop. We often write all this helpful stuff and the OP just disappears. We never know what happened.

Matt