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zeusmann's avatar
zeusmann
Explorer
Mar 13, 2015

Duo therm brisk air help!!!!

I have a old terry trailer with a duo therm brisk air rooftop unit.
A lot of the Time I have to keep flipping the unit on and off to get the compressor to kick on. The air will blow ice cold but when the thermostat turns it off the compressor won't kick back on unless I mess with the thermostat adjustment or turn the unit off and on until it kicks on. The fan will always run no matter what.
Most times when I am able to get the compressor to start there is a short delay and the lights dim like its drawing a lot of power.
From what research I could do and understand it sounds like I may have a bad capacitor but I dont really know too much about this stuff. I am a fairly handy person and could do some simple things myself but most electrical is over my head.

Someone please help me figure this out so I can get my ac working right. I will try my best to give the most information and describe things to the best of my knowledge.
  • j-d's avatar
    j-d
    Explorer II
    Mar 16, 2015
    Unless you have owner documents, I think it's a Roof-Only job. Somebody correct me, but I don't think taking the bottom/inside portion off will show anything helpful. I have only worked on Coleman. On those, you can see a label on the sheet metal after removing the plastic shroud. Turn POWER OFF before you go up. Again on Coleman, there's a little sheet metal cover over the capacitors. If you can get the Model/Serial information, great. If you can photograph the Label, that's great. If you can photo the Capacitors, good again. If you can, without getting zapped by charged capacitors, write down the nomenclature on the Capacitors. Or you can short across the terminals of each Capacitor with the blade of an insulated tool and approach them safely POWER OFF REMEMBER.
    Capacitor nomenclature would be something like:
    40 MFD at 440 Volts. There should be a Compressor Run Cap and a Fan Run Cap. These may be combined on one "can." Then more likely than not a Compressor Start Cap. That one's likely to be plastic.
    IF you can do it safely, get up there and get the info. While you're there make sure the fan shaft spins freely.
    Waiting and ready to help.
  • zeusmann's avatar
    zeusmann
    Explorer
    Mar 16, 2015
    Bump..... Was going to try and get on the roof today and check under the cover. Any info on where to look for a model # and capacitor model#
  • zeusmann's avatar
    zeusmann
    Explorer
    Mar 13, 2015
    How do I get the model #? If I have to go on the roof it will be a day or two so this rain can pass.
  • Chris_Bryant's avatar
    Chris_Bryant
    Explorer II
    Mar 13, 2015
    We really need a model number- there were some BriskAir units that had a shure start option, which would not start the compressor if the voltage was low, plus had a time delay built in.
    Are the controls the basic mechanical switch and thermostat on the roof unit, or is it a wall thermostat?
  • ScottG's avatar
    ScottG
    Nomad
    Mar 13, 2015
    It sounds like the hard start capacitor is blown which is a common problem. You need to go up top and take a look at it. The cap is a round black component about the size of a roll of silver dollars. It's located on the passenger side of the AC unit.
    It may or may not appear corroded on top or it may look askew. It could also look perfectly fine and still be bad.
    I would start by buying a new one for it. Just get a "Hard start kit".
    If your located anywhere close to me, I'd be glad to look at it.

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