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Shot-N-Az's avatar
Shot-N-Az
Explorer
Nov 07, 2015

I need to ensure I have foam gaskets seated properly

I'm replacing a ducted roof a/c unit and need to know if I have the unit placed correctly and the gaskets are seated properly. Of course, I can't see the gaskets.

What is the accepted method for doing this? Can you put talcum powder or a similar substance on the surface to be sealed to see where the gaskets are seating on it?

5 Replies

  • dougrainer's avatar
    dougrainer
    Nomad
    Nov 07, 2015
    Shot-N-Az wrote:
    Hey, that's an informative article but it doesn't address what I'm trying to do.

    The gaskets are affixed to the A/C, and there is a gasket within a gasket separating the air discharge and air return portions of the ducting manifold. There is no access to the A/C unit from inside the motorhome.

    So, not only do I need to know that the gasket is properly seated on the 14"X14" roof opening, but I also need to know that the second gasket is seated properly as well.

    The old and new bolt holes do not line up, so that's of no help either.


    If you still have the Newmar.
    1. Once the old is pulled you will see the extra gasket on the old AC. Just match the new gasket to the new AC
    2. Yes, the holes do not line up on older Dometic's. The REAR 2 lag bolts should line up. You then need to measure and drill 2 new holes that match the old AC pan. DO NOT DRILL NEW HOLES IN THE ROOF. Doug
  • Shot-N-Az's avatar
    Shot-N-Az
    Explorer
    Nov 07, 2015
    Hey, that's an informative article but it doesn't address what I'm trying to do.

    The gaskets are affixed to the A/C, and there is a gasket within a gasket separating the air discharge and air return portions of the ducting manifold. There is no access to the A/C unit from inside the motorhome.

    So, not only do I need to know that the gasket is properly seated on the 14"X14" roof opening, but I also need to know that the second gasket is seated properly as well.

    The old and new bolt holes do not line up, so that's of no help either.
  • MEXICOWANDERER's avatar
    MEXICOWANDERER
    Explorer
    Nov 07, 2015
    To keep mine in place, I cleaned all surfaces with alcohol then used multiple tiny dots of yellow snot weatherstrip adhesive around the coaming, waited and hour or two then placed the AC on top. As mentioned above the correct tightening of the unit to the roof has to be done both with knowledge and care. Boy did I ever find that out the hard way :(
  • LynnandCarol's avatar
    LynnandCarol
    Explorer
    Nov 07, 2015
    http://www.motorhome.com/rv-how-to/roof-ac-gasket-replacement/ This link may help! The gasket should just be tight, not super tight.

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