Issue to check with AC in Thor ACE

[davepetroski]

We installed a new bedroom AC in my 2016 ACE 30.2 this weekend. The unit is great and we are thrilled about the addition. Problem is that the little 13.5 BTU was putting out way more cooling than the existing 15 BTU unit. As much as I'd like to say it was my installation skills obviously something was wrong. With my new knowledge of RV air conditioning I opened the covers on the factory unit to investigate.

To my surprise the plastic shroud or cover of the Coleman unit has a plastic channel. This channel is used to align and hold the duct board between the return and cold air supply. This duct board has nothing else holding it and its location was not the optimal position. The cold air was entering the return directly from the supply fan and the temperature sensor was experiencing this colder air. The unit thought the coach was cooled and would cycle instead of producing more cool air. I know this is a difficult thing to explain so I attached some pictures. I ended up taping the board in place in moving it out of the channel of the cover. Bottom line the AC is way way colder now, something definitely worth checking in all RVs. All that is needed to do is remove the filters and 4 screws to investigate.

Another discovery that should have been obvious to me is that the ceiling vents are using only Styrofoam channels for cooling. The furnace at the ground level services the heat via different vents. I have read numerous forum articles that discuss the vents coming loose but there is really nothing to come loose. Just two channels of Styrofoam left and right that run the length of the RV. There is nothing to come loose. Best option is to make sure the return and supply is isolated for optimal performance and keeping the sensor reading properly. Yesterday the temperature outside was 107-108 and the combination of the 2 Coleman units had the coach extremely comfortable. What impressed me the most was I did the install during the day around 2 pm and the coach cooled down at the most extreme temperature of the day. I am looking next to insulate the windshield from the sun with a magneshade or similar. We feel with the 2 AC units running efficiently we will be well prepared particularly if we can insulate off the windshield heat source.

[Oneilkeys]

I found the same thing with the AC unit in my 2016 Axis and used duct tape to secure that buffer piece and make sure it did not bleed air. Installing the four inch circular vent in the shroud of the Coleman (as Shown in previous threads) makes an incredible difference in air flow to the living area - as you would imagine based on davepetroski's observations. The small vents seem like a good idea to direct air cooling flow to different areas in the RV, but they block a lot of air from ever getting into the RV and the channels are right up next to the roof where they are heated by the sun.