Roof top AC replacement

[jjrbus]

I have a 35 foot spray foamed coach, insulated windows, Saudi bus with the double roof. Bus is painted ultra white for low heat gain. I have 2 13.5K Dometic Brisk air conditioners. Most of the time 1 unit seems to be too much capacity. I could be wrong.
I have a 30 amp service so can only run 1 at a time. Adding a 50 amp service will do me no good as most places I stay are 30 amp. 1 AC will cool the bus 99% of the time. However the distribution is not perfect. I find myself turning off the front, turning on the back, turning off the back, turning on the front etc.
I see they now sell 7&8K btu units which draw from 8 to 9.1 amps. there may be more out there, this is at camping world. The catalog does not show locked rotor amps.
I'm thinking if I have to replace a unit, I would put a small one in the bedroom/bathroom as the 13.5K is definately too big there.
My question is would a 30 amp service start and run an 8k and the 13k at the same time. Would 2 8K's run together on a 30 amp service? Does anybody have any experience with these units, I do not want to end up like Jerry L. did. Am I missing anything?
                                            Jim

[Nick Badame Refrig/ACC]

Sure Jim,

It would work if you don't expierence problems like low voltage in a park, or if you are only running the A/C's and nothing else.

The only glitch would be if the two compressors were to start at the same time. You would exceed the 30 amps and

possibly trip the breaker. Start up amps on compressors can range from doubble to tripple the normal amp draw depending

on how hot they are at the time. But, I beleve most of the time you would run trouble free.

Dometic does have a 7500 btu unit that you discribe.

good luck
Nick-

[niles500]

Jim - An automatic switching device to provide 120 volts alternatively between the 2 A/C's has been discussed on one of the boards before - HTH

[TomC]

Sounds to me like you're not adjusting the thermostat correctly-since it gets too cold for you.  When the coach gets to the temp you want, start rotating the thermostat towards hotter slowly until you here the compressor quit-it'll be adjusted.  Then you won't have to run back and forth turning one on then the other.  I have three roof airs that I have found the setting for a comfortable 72 degrees.  I have many times run two on 30 amps.  Also-Camping World makes an automatic switching device that cycles the front and back. Good Luck, TomC

[Jerry32]

I have run two 13.5 units at the same time on 30 amps but you can't turn anything else on with heavy current. Jerry