Air conditioner question?

[Wijames]

My RV has two air units on the roof. One is a standard RV unit with the controls and vents on the inside at the air conditioner. The other has the controls on the wall like my home unit with ceiling vents in various places. Are the two units basically the same? I'm asking because my standard unit is working very good but the one controled with the trermostat is not blowing cold so I'm probably going to need to replace it. just wondering what the difference is in the two units so I know what to look for.
Hope this makes sense.

[j-d]

Answering this requires Model Numbers for both A/C units and some research. Or Models and some wise input from an experienced tech. Of whom we have at least two, Chris and Doug. It may or may not be simple to switch the control system from one A/C to the other.

Nice thing about Coleman is access to parts lists, wiring diagrams, etc. Dometic may be the same, and I just haven't had a need to look.

Three basic things can go wrong with RV A/C's

1. Compressor may fail. This is what we all fear and it's relatively rare.

2. Sealed System (coils and tubing) may leak the refrigerant. Also rare.

3. Something Electrical

Replacement is appropriate in 1. and 2. since most of us can't do A/C repairs and an RV Tech will cost as much as a new A/C for DIY install.

But 3. can be something very simple and inexpensive. Thermostat, Switch, Wiring, or the VERY COMMON problem, failed Capacitors. Your Compressor depends on a Run Capacitor. It may also have a Start Capacitor. If it has Start, it'll also have some form of device to drop Start out of the circuit once the Compressor starts.

We can help with troubleshooting the one that is "isn't blowing cold" but we'd need more symptoms and you to end up on the roof with shrouding removed for inspection and some simple checks. You'd need a Spotter to open the Breaker for part of the checking and close it to see if you made a difference.

Coleman fan myself. We had one cool (and remove humidity) in FL over 25 years. Our current one does the same, just not as old yet. Dometic may well be better and I'm just ignorant. That said, Parts and Service are very important to me. I'll settle for a pinch less performance if the service support is better.

OH... This is a better Tech Issues question than a Class C question. A/C and related problems are common to all RV types, and the techs tend to cruise the Tech Issues forum more frequently. You can Contact Moderator and ask the thread to be moved...

[mdamerell]

Bumpyroad wrote:

mdamerell wrote:
An AC unit sits on the roof. Once it comes into the coach it can have one of two assemblies mounted on it. Ducted (controlled by a thermostat on wall) and a non-ducted (which all the controls on the unit as you see it). Depending on the size of your rig the bedroom unit may be the same size as the Living room unit or a little smaller.

my TT has a non-ducted with thermostat on the wall.
bumpy

Cool, when I was researching for a 2nd unit I did not see that option.

[The_Logans]

Any chance that it's just the thermostat that's gone bad? We thought that the AC was bad, because no matter how we set the switches on the thermostat, only the fan ran... the compressor never kicked on. An honest AC guy told us all we needed was a new 12.00 thermostat. Yup, after that it worked fine.

Whew!

[snowdance]

Big Katuna wrote:
I won't disagree that the Dometic is a better, quieter, unit but my Colemans work fine in Florida 100 degree summers.

I would not blindly replace the ac yet. Have a tech look at it. It might be a capacitor or control board.

I too would check the unit or have it checked before buying a new one. Often its some thing simple. Our Coleman works great up to 117 degrees. The Dometic we had first was repaired 3 times and just kept failing. But seems everyone just builds bad stuff from time to time. So we just replaced it with a coleman and no more problems.

[Bumpyroad]

mdamerell wrote:
An AC unit sits on the roof. Once it comes into the coach it can have one of two assemblies mounted on it. Ducted (controlled by a thermostat on wall) and a non-ducted (which all the controls on the unit as you see it). Depending on the size of your rig the bedroom unit may be the same size as the Living room unit or a little smaller.

my TT has a non-ducted with thermostat on the wall.
bumpy

[Big_Katuna]

I won't disagree that the Dometic is a better, quieter, unit but my Colemans work fine in Florida 100 degree summers.

I would not blindly replace the ac yet. Have a tech look at it. It might be a capacitor or control board.

[navegator]

If the A/C needs replacing DO NOT replace with a Coleman unit, they do not work as good as the Dometic, plus the filter can not be washed while the unit is running or the inside fins cleaned with a vacuum cleaner the evaporator fins are inaccessible.

The worst part of the Coleman units is that it does not cool after the temps outside reach 80 or more, after that is just makes noise and the temps inside go up, the Dometic we had would keep the rig cold in 120+ with no sweat, with the Coleman the inside temp stays at 80 to 95 depending on the outside temperature.

Please do not tell me how good the Coleman's are, we had a Dometic that lasted 15 years, now we have the Coleman, same hot dessert, big difference.

No we did not purchase it, insurance repair, el cheapo.

navegator

[mdamerell]

An AC unit sits on the roof. Once it comes into the coach it can have one of two assemblies mounted on it. Ducted (controlled by a thermostat on wall) and a non-ducted (which all the controls on the unit as you see it). Depending on the size of your rig the bedroom unit may be the same size as the Living room unit or a little smaller.

I'd pop the inside cover off and there will be a foam dust screen that I would wash or change. Look up in the unit and if the coil in there is dirty you can gently vacuum it. Under the cover on the roof the cooling coils may be dirty and require cleaning. If everything is clean then it maybe low on charge meaning there is a leak.

If you can find a matching unit you can probably get by with only replacing the roof unit and not have to replace the internal portion.

[Bumpyroad]

other than the one acting similar to a house aC and the other like an old RV AC, don't think there is much difference in the "science" involved between them. wall controls are nice, can run it without having that noisy fan blasting 24/7,
bumpy