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Rating: 3 votes, 5.00 average.

15K AC upgrade and proper AC drip cup install done

Posted 11-30-2018 at 07:04 PM by GMFL
Updated 11-30-2018 at 07:15 PM by GMFL

That past summer we had enough! Our factory 13.5K AC was just not up to the task of keeping our 23D cool in the hot Florida beach summers. We like to go to the beach at least 4 weeks in the summer and if we happened to get a site at our favorite beach park (Camp Gulf DESTIN) that was not shaded we were T-O-A-S-T.
Our 13.5K unit would keep the inside of our unit nice in. The morning and at night, but mid day it would struggle to keep the inside temp in the 80s.
Soooooooo we upgraded to a 15K unit, and what a difference it has make in our lives. This new unit will keep the inside temp at whatever temp the thermostat is set to. (FL Keys in August, no problem)
While preparing to do this upgrade I discovered that the Airstream factory fails to install any of the Dometic units correctly or according to Dometicís guidelines. Units with Drip Cups installed are suppose to have TWO base gaskets installed. Airstream only uses one. By only using one gasket the Drip Cups rest on the roof and cause undue stress on the cups and the hose connections, which in my case caused one of the Drip Cut to crack.
The swap from 13.5K to 15K unit was straight forward and required no modifications to complete. The hardest part of the entire installwas getting the old unit off the roof and the new unit on the roof. The unit weighs right at 100lbs.
There is a dip switch inside the AC control panel that has to be turned on so the thermostat will recognize that there is a furnace in the system.
I painted my new Drip Cups to help prevent sun damage in the future. I also installed a Micro Air Easy Start on the new 15K unit while I had it on the workbench, which was a lot easier to install it on the ground vs on the roof.
Also note the difference in Drip Cup heigh from the factory install with one gasket and the proper install with two gaskets. The two gasket install allows the Drip Cups to float and not have pressure applied from the roof.
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Total Comments 7


  1. Old Comment
    Boxite's Avatar
    THIS is the type of posting I really appreciate. THANK YOU. Excellent job!
    Posted 12-02-2018 at 08:48 AM by Boxite Boxite is offline
  2. Old Comment
    GMFL's Avatar
    Thanks for the kind words. I’m working on posting detailed write ups on all my mods.
    Posted 12-02-2018 at 09:31 PM by GMFL GMFL is offline
  3. Old Comment
    harryk's Avatar
    OK, I am finally beginning to understand what the cups are for....but I have to ask, does the drip tube have to go thru the gasket to get inside the rv to then connect to the main down the wall drip tube ? Originally I thought the cups were on the interior part of the ac. On the old system wasn't there a drip pan inside accessible from the interior ?
    Posted 03-18-2019 at 02:51 PM by harryk harryk is offline
  4. Old Comment
    GMFL's Avatar
    The drip tube does enter through the gasket. One tube off each cup then connect to a tee fitting and drain out the main drain tube inside the trailer wall.
    Posted 03-18-2019 at 06:15 PM by GMFL GMFL is offline
  5. Old Comment
    Ditter's Avatar
    Did you install a remote thermostat or was it built in lower unit?

    Can you share lower unit part number?

    I received a quote form Airstream $2500. To do swap. The weight of unit will be hard to handle but I canít justify spending that much for install

    Airstream shop said I had to install wall thermostat that is why asked about your lower unit.
    Thanks for your help and taking time to share with us.

    Posted 04-10-2019 at 08:23 AM by Ditter Ditter is offline
  6. Old Comment
    GMFL's Avatar
    Sorry I missed this question.
    This was a direct swap out for my 13.5K unit. I used the thermostat was already mounted in the wall.
    The unit could either be operated with a wall mounted thermostat or manual controls on the air distribution box.
    Dometic sells two different air distribution boxes based on your needs.
    Posted 08-05-2019 at 07:58 AM by GMFL GMFL is offline
  7. Old Comment
    hmhRV's Avatar
    Hi GMFL'
    Great job and great DOCUMENTATION!!
    I am preparing to swap out my old Coleman 13.5 for a new 15K Coleman and add the drip cups and was wondering about the 2 gaskets. The drip cup instructions also state to squish the 2 gaskets down to the size of 1 gasket for the Coleman.
    Sure appreciate you providing the pictures.
    Posted 09-04-2020 at 11:55 AM by hmhRV hmhRV is offline

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