Last year our roof top AC unit died in the late heat of summer. The compressor/gas system had issues. The hot side of the compressor system was hot and the cold side was also hot. I really do not know if the compressor itself went out internally or there was a gas leak in the system. These RV units are not really setup well for recharging and then the gas in the older units is outlawed now.
In this case I chose to replace the roof unit. After living through high heat in a camper, one get's spoiled real quick, you need an AC unit to have a good sleep at night. After some research, Dometic discontinued the original Brisk Air unit like ours and enough time had passed I could not get a new older style one.
So now to get a new design unit. After researching, the gas systems are different and the entire unit is redesigned on the Brisk Air II. The new gas system requires a higher pressure and the noise on some of the Penguin units is close to obnoxious. I have heard them in one of my buddies 5'er. The higher pressure means the compressor has to work harder to get it that high and noise comes from this. OK not going the thin profile route but even the normal unit still uses the higher pressure gas due to regulations. And the unit does not appear as rugged as the older Brisk Air.
The next item is the control system. To be more efficient, I think this is why they are doing it, the new control units have the fan run non stop and only cycle the compressor. Well on a camper, for folks who like the great outdoors, hearing a AC unit run non stop is not something we like.
So the hunt was on. The new units just did not appeal to me even though the reports are they cool well and the control feature of not shutting off was a real turn off.
I found the Dometic Commercial Grade unit. H'mm OK this is different. Yes it still uses the newer gas system, but it is built significantly different. These are used more on commercial applications, concession stand trailers etc. I called Dometic customer service and asked about this unit and if it was OK to use on a RV camper and will it fit in the standard 14 x 14 opening? They said by all means, yes. Then I went to, does it use the standard 6 prong plug of my older unit and can I use my original analog control unit? She looked it up and yes, it will plug right in and your original ducted air box will work just fine.
Great! These means I only need the roof unit and I get a much better built AC unit, better warranty and the system will shut down the fan when the T stat is satisfied. I asked, why are these not offered on RV's? Then the rest of the story comes out... She said, the RV industry is so price competitive, they do not offer the commercial unit. The RV manufactures only request the standard unit. Granted the cost is much more for the commercial unit but it is built better and the cost reflects what you are getting. Since we plan on keeping the T310SR for a good long time, we made the choice to get the better unit. This cost choice is about double, but I was doing the install so no cost from the install labor, only the roof unit.
We ordered one from American RV in CA. I have bought from them before and they handled this transaction very good. Due to the weight, it had to be a truck shipment which was not a problem. I had it shipped to the local freight terminal and I went to pick it up. You could have it shipped to your house, but that would cost more for a drop gate truck.
Here is the removal. I'll do this in pics.
You start on the inside. Take down the control unit and the air box.
Unscrew the control unit from the large air box plate, then take down the air box. There are 4 long screws/bolts in the corners that hold the roof unit in place. Take them out and the air box will come out. The foam insulation is glued to the wood opening. I used a sharp putty knife to carefully take this off to reuse it. Here is the air box on the camper floor
Take the 2 sheet metal screws off the lower air box plate for the control unit
You need to unhook the control unit. It is all plug in
And take the frost control off the evaporator coil
Here is what the ceiling ducts look like. There are 2 of these. They are a foam core duct with foil on the outside.
Next is up on the roof. Tarp and plywood down as this is not a walk on roof..
The roof unit off, yuk.. a bit dirty under there since Nov 2003 when the camper was built
Also notice there was bolts on the bottom that about cut through the roof
The old unit down on the ladder/scaffold
And the bolts that were resting on the rubber. I do not know if the original gasket was over compressed or not. The bolts inside holding the AC unit down were not loose but it was for sure too low.
I'll do the install on the next reply