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JollyCamper · 08-05-2019, 09:39 PM

Good day to all! I am about to start back to work on my 1978 Class C El Dorado, and AC replacement is first on the list. I picked up a used Dometic Brisk 2 today, all parts besides the wall mount thermostat, from a ducted unit. My unit is non ducted. The old unit is a Dometic also, so I may be able to get creative and re-use the old ceiling assembly, but I am not sure yet. If I use a wall mount thermostat in my rig, I don’t need to use any of the controls on the old ceiling unit, correct? At that point I would just be using it as an air plenum for the vents. Am I looking at this all wrong; or is it possible?

jeepfreak · 08-07-2019, 05:09 PM

You have to many questions and not enough info. The new one was most likely controlled by low voltage off the wall mounted t-stat . The old one probably had a line(110volt) t-stat mounted in the ceiling controls. You need to find out more about the new one.

JollyCamper · 08-08-2019, 07:09 AM

The new unit does use a wall mounted thermostat. I plan on installing one, but I am wondering about using the old ceiling unit primarily for its vents to distribute the air.

leadman · 08-08-2019, 09:22 AM

If it fits you can probably use it without hooking up the controls in it.
Don't know for sure on a Dometic but my Coleman Mach II has a relay panel in the air intake area from the coach. This runs the a/c from the wall mounted thermostat. My coach is ducted.
Since you seem to have a non ducted unit now you might have to remove a plate blocking the cold air from going out the ceiling vent on your replacement unit.

JollyCamper · 08-14-2019, 11:17 AM

I got the unit installed today, and it works! I am not finished with the install, but it is functioning. I have it installed using the new Dometic Brisk 2 roof unit, and everything inside is the vintage Dometic ceiling unit. The bolt patter to attach the ceiling unit to the roof unit was different so I drilled new holes in the ceiling assembly frame and bolted them together. I then took the wiring controller for the new unit, removed the wiring and installed it onto the control box for the old unit. I will need to make a small piece of ducting to keep the cold air contained between the cold air outlet on the roof unit and into the “plenum” of the ceiling unit. It is sad, I updated my AC by 30 years and lost features...I lost medium can speed and my heat strip. Oh well, I think it was worth it!