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Topic: Duo Therm AC maintanance (Read 1611 times) previous topic - next topic

Duo Therm AC maintanance

My one ac unit in the back isblowing cold air but the front one is blowing cool air (which is not enough to cool the coach to the degree the thermostat is set at.
The inside filter is easy enough to clean how about the outside condenser.
Any videos I can watch that shows how to clean up top and any helpful hints.
Thanks

Re: Duo Therm AC maintanance

Reply #1 –
I took a picture of the vent inside. There is a six sided mesh up there that you can see is very dirty. I'm not sure if I clean it from below or go outside and clean it on the roof.
Thanks

Re: Duo Therm AC maintanance

Reply #2 –
I recently did a deep clean of our roof air units.

I turned off the AC and DC.
I removed the inside covers.
I sprayed the evaporator fins liberally with Ac fin cleaner.
I used a pump-up spray bottle to rinse the evaporator fins.
I put down some towels on the floor below the AC units.
I climbed up!
I removed the exterior covers for the roof ACs.
I sprayed the fins liberally with fin cleaner.
I used a garden hose and sprayer to flush the exterior units until the water ran clean.
I cleaned up the mess inside under the ACs.
I let stuff air dry for a while.
I took apart the interior plug-in connections and wiped them down.
I let stuff air dry for a while longer.
Turned on the AC and DC, checked for proper operation, and reinstalled all of the covers.

This may be more aggressive than you want to get, but it worked well.

Re: Duo Therm AC maintanance

Reply #3 –
It looks like the AC was run without a filter, or with the filter poorly placed.  Clean that from the inside.  I looked for a better filter - one that would stay rigid, but I could not find anything that would fit.

Re: Duo Therm AC maintanance

Reply #5 –
Thanks, very useful. I will try cleaning before I try anything else.

Re: Duo Therm AC maintanance

Reply #6 –
When we picked up our coach front ac operated poorly. Installed service ports on both units and serviced both with Freon. Both were low and both perform very well now. My local HVAC shop did service.
Scott

Re: Duo Therm AC maintanance

Reply #7 –
The evaporator on most roof A/C's can only really be cleaned well from the roof.  Not a complex job, but takes time.

If, when you first turn on the A/C, it smells like a "wet dog", it is well past time to clean the evaporator.

Re: Duo Therm AC maintanance

Reply #8 –
Add removing metal panel on roof side to gain access to evap coil to Matt's post.

Re: Duo Therm AC maintanance

Reply #11 –
Forgot to say that when I replace the filter media I sandwich in a couple of dryer sheets to make everything smell good.

Re: Duo Therm AC maintanance

Reply #12 –
I just cleaned both my duo therm units - 1998 U270. Removed covers, used non rinse foaming coil cleaner, and removed sheet metal cover on evaporator coils. Rinsed with spay bottle with towel below inside. They did not work right afterwards. Called mobile repair guy and he unplugged both telephone line connections and reconnected a few times. Magic fix.  No pain no gain.

Re: Duo Therm AC maintanance

Reply #13 –
T-Man, We put plastic chicken-wire-looking screen in place to keep filter sandwiched between this new screen and the outside removable panel. Filter now stays flat and is not sucked into input space.

Re: Duo Therm AC maintanance

Reply #14 –
So I cleaned the coils up top but it still it blows cool air.
Every local HVAC place I call doesn't do rv roof air-conditioners.
And the RV places don't add Freon; they just replace old units. I guess the new ones are self contained and you just replace them.
Any ideas.  I know we are not supposed to do this ourselves but that may be an option.
One of my first cars was a 1968 Chevelle 327.  I used to do most of the mechanical work including adding Freon. But that was in the good old days when life was simple.

Thanks

Re: Duo Therm AC maintanance

Reply #15 –
Why not add freon. I would.

Re: Duo Therm AC maintanance

Reply #16 –
Rick, I assume the compressor motor is running in the Cool setting ? Do you get the same 'cool' air when running on Fan setting ?

Re: Duo Therm AC maintanance

Reply #17 –
Someone please let know if this doesn't hold true with these units but... on most RV AC units I've worked on, there is a wall that separates the intake (hot air) and output (cold air). The air flows in a U or horseshoe shaped pattern, starting in the coach, up and over the "wall" through the cooling fins, and back down into the coach. I've seen this wall get dislodged or moved and then you've basically short circuited the loop and your hot and cold air start mixing, resulting in "cool but not cold" air.

Usually you can visually inspect the wall from inside the coach by taking out the intake vents and looking up in there with a flashlight.
 

Re: Duo Therm AC maintanance

Reply #18 –
Good point Elliott.  I always have a roll of quality aluminum duct tape to repair any air leaks.