Is this normal AC operation?

[mick2268]

OK, so My 29'Cougar/Dometic has a history of AC not doing well, by that I mean struggling, and often freezing up. However, I spent some time this winter re-taping the ducts up in the unit and thought I had it fixed. The main problem up till now has been freeze up, yes, even with it on high and all vents open for full flow.

Ran it 6 hours yesterday, and NO FREEZE UP...Yay!! But thermometer still showed over 80 in the unit. Here are the specifics.

It was in my shop, and I turned it on around noon. So no sun, but it was pretty warm in there, especially 12' high near the unit. After six hours, it showed no signs of freeze, water was still dripping so it was still pulling moisture out. I showed 74 degrees coming out of the main vent, and showed at least 95 outside at the unit; maybe even 100 up on top.

But it seems to me she should be blowing colder air. The only thing left I can think of would be that the Freon is low. I know that it's a sealed system, and a pretty new unit, but is there anything else it could be? Cold low Freon be a possibility? My thought is that if I had a leak, it would be empty by now, but what say you all??

Thanks...Mick

[allen8106]

Make sure you are running the AC on high speed fan, low speed fan will cause the AC to ice up. Low speed is for heating/furnace use only.

[jerem0621]

The RV air conditioners do not have service ports to charge the Freon. I have heard that some have the service ports brazed on, but I am not sure if you can find someone to braze them on.

Thanks!

Jeremiah

[Ed9824v]

Not sure what they charge should be a lot cheaper than new.

[mick2268]

It's never worked well since we've had it, so wondering if it just didn't get charged properly at factory?

So you're thinking that cost to recharge would justify just dropping a new unit in?

[Ed9824v]

Acting very much like a low charge.
Either it devoloped a leak or has a very small leak from the factory. Ideally you want to fix the leak b4 charging and to use soldered in valve to charge. Would not hurt to take spray bottle with soap now to look for a leak with the bubbles at the leak

[jerem0621]

mick2268 wrote:
Ok so did all those things, and currently have 68 degrees coming out, with 78 going in. will give it awhile and check again. Did notice that very quickly the upper few coils were frosting over, while below they were tepid.

So what should I expect to pay one of the mobile guys to recharge the Freon? Confirmed it is a 2014 dometic 15k btu.

You will be looking at a new AC unit. From what I understand the RV AC’s are not serviceable when it comes to Freon.

Thanks!

Jeremiah

[mick2268]

Ok so did all those things, and currently have 68 degrees coming out, with 78 going in. will give it awhile and check again. Did notice that very quickly the upper few coils were frosting over, while below they were tepid.

So what should I expect to pay one of the mobile guys to recharge the Freon? Confirmed it is a 2014 dometic 15k btu.

[Ed9824v]

Can use just 30wt non detergent

[mick2268]

Thanks Guys!! Is there a particular oil I should use on the fan motor?

[Jay_Pat]

I don't remember is this video is the same brand.
Should be a helpful video for you.

Cleaning Video.

[Ed9824v]

inside is the evaporator and outside on top in the condenser. If you have access to the coil bends on each side of the coil that is a good place to feel the cold and the whole row from top to bottom should be cool if only a few then there is likely a low charge. but it is a good time to clean the outside coils that can lower the work the usit need to do and the high pressure that it sees if clean. I think they make a spray solution that cleans the coil, but a low press spray of water to flush the coil clean. too much you could get water inside so be careful. From the top the entire evaporator will most likely be covered. Good time to oil the fan motor usually a small plastic or aluminum plug is removed and a few drops of oil on each end bell of the motor. good luck be safe.

[mick2268]

OK, so forgive my ignorance, but can you explain further? So I can access coils from inside the camper on the intake side. Which ones are those? And of course I can get on top tomorrow and pull cover to access the others, which are those?

To be more specific on unit, it is a Dometic brisk Air, not sure if it's 13.5 or 15K btu, but assume the smaller on a 2014 cougar light 29'

[Ed9824v]

mick2268 wrote:
Yeah, NO. Had 80-85 going in, and 74 coming out of the main vent right next to it.

Is the evaporator and the condenser clean?? if so I would tend to believe that is low on charge. The fact that it freezes up make me lean toward a low charge. If you can get access to the evaportor the coil that cold air comes out of. and run your fingers along the end coil bends you should have all the the bends cold if just a few are cold and the other warm good sign of a low charge also.

[mick2268]

Yeah, NO. Had 80-85 going in, and 74 coming out of the main vent right next to it.