Dometic A/C

[Platinum 1]

My A/C was working fine, I put the heat on to take the chill off while I was doing some things inside. I then had to turn it off as it was getting hot in the rv.
A week later we were getting ready to take a trip and I put it back on heat to warm it up before we left that morning.
The unit started up and when I came back it about 10 minutes later I noticed it was blowing cold air. So I kept trying to get the heat on but it was only cold. The compressor was running sounded ok but no heat. Now I know you can’t replace Freon in them as there are no valves for that, but it surprises me that I would have lost Freon that fast. So any help, ideas would be appreciated.
The unit is a 2011 rv with 60,145 miles on it, it’s a 13,500 hp unit.
If I have to replace it, it surely won’t be with another dometic unit.

[Old Scout]

Curious, what the ambient air temp? Was it the same both days? Most RV heat pumps usually struggle to provide heat below 40 degrees....

[Platinum 1]

The temp was about the same it was 50 degrees, one of my thoughts was is it possible the reversing valve got stuck and is in the cold mode only. I tried putting a/c to cool but no change. I got up on the roof and could feel the copper pipe coming out of the compressor getting warmer, but it didn’t seem to go any further down the pipe. The same happen on the cool cycle. The compressor didn’t make any different noise like it was low on Freon.

[Jmac00]

so you have a heat pump, not just an air conditioner.

If thats the case, it could be the Reversing valve solenoid has gone bad, or burned up and is stuck. Does the unit still blow *cold* air, as in a/c mode?

If it was a condenser fan motor, the compressor would eventually over heat and stop, hopefully on thermal over load.

could also be the control module?

could also be on of the remote sensors?

How good are you with a volt meter? if not, I would suggest a Pro look at it

[Platinum 1]

Yes heat pump, thought I mentioned that. Guess I didn’t.
Yes I use a volt meter all the time.
I tried putting it on a/c to cool and it sounds the same, compressor turns on but the problem the temp outside is in the low 40s and the air coming out of the ducts is real cold, and the problem the temp inside rv is below 45 degrees. I hope to get the rv next week and bring it home, been trying to but weather hasn’t cooperated. Been raining or snowing, and this weekend high wind warnings.
The solenoid for the reversing valve I check before we went on our trip and I could feel it had magnetism when moving it on the shaft.
So if you could give me some more info to Ck it would be very appreciated.
I really don’t want to go to CWorld as they’re expensive and not sure they really know what they are doing, plus they’ll want to sell me a new one. If I have to get a new one it won’t be from them.

[jjrbus]

People pick on me for my Frankonditioner. A window AC modified to roof air. Not happy with what is available in RV units. I would put in a mini split, however do not have room for the evaporator.



They seem to not like links posted on this forum. I would look for a DIY AC forum. While they do not do a lot of RV AC, the systems are similar and they may be able to point you in the right direction for trouble shooting. It could be something simple??






























































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[Platinum 1]

That’s a good idea, I’ll look for a a/c forum.
Thank you for your suggestion

[Jmac00]

when was the last time the coils were cleaned, I mean with coil cleaner, you can get a can of Nu-Calgon Blackhawk no-rinse coil cleaner for 8 bucks.

If everything seems to be working, the reversing valve seems to be ok, and the fans are running, I would say go look for a leak, but without service valves, that might be tough. You could take a temperature reading of the suction and liquid lines, if the temps are the same, I would say your compressor is shot, it maybe running but the valves are gone.

what does a Dometic a/c use for refrigerant R-134a? I don't know, Im a residential guy.

can you pull the clip off the Reversing valve coil and actually pull the coil up and down on the stem, while its running, you should hear the valve moving refrigerant back and forth, it should be a fairly loud 'Hiss" type sound. Pull the coil up for a minute or so, then put it back. If your not getting that "hiss", your probably out of Refrigerant ( don't just pull it up and put it back. pull it up/off, give it a minute and put it back)

[Platinum 1]

Ok, I’ll try that to. I’ve had the valve off be fore to make sure it wasn’t stuck from corrosion. That was last fall. Coils were cleaned then to.
Thank you for your help

[Platinum 1]

Well,
I finally had time and better weather to get on top of the roof and check out the ac. I found that I had a leak of Freon on the copper line that connects to the condenser unit. The copper pipe shows Iloilo stain and the curved copper pipes on the condenser show oil stain. I spoke to a buddy of mine and he’s going to come over and we plan on added a sweated on Freon connection and repair the copper pipe that shows the leak. And we’ll see if it works out. I’ll let you all know after we do it. I want to thank All that replied to my ac issue.
The Best to you all.

[Jmac00]

Originally Posted by Platinum 1

Well,
I finally had time and better weather to get on top of the roof and check out the ac. I found that I had a leak of Freon on the copper line that connects to the condenser unit. The copper pipe shows Iloilo stain and the curved copper pipes on the condenser show oil stain. I spoke to a buddy of mine and he’s going to come over and we plan on added a sweated on Freon connection and repair the copper pipe that shows the leak. And we’ll see if it works out. I’ll let you all know after we do it. I want to thank All that replied to my ac issue.
The Best to you all.

IS he a HVAC guy? make sure he uses nitrogen when sweating in fittings, and possibly add a suction line filter/drier, if there is room. and make sure he pulls a good vacuum, which on a system this small shouldn't take more than a couple minutes. you want to pull a minimum of 250µ (microns) or less. less is better.

Good luck

[Platinum 1]

Hi,
Yes he’s a HVAC guy, he’s my neighbor. Thank you for your information we’ll see if we have the space for the fil/dry I’m not sure, Dometic sure uses cheap materials.
At least on this unit. If it doesn’t work out then my replacement will be the recpro houghton unit, it’s has 2 motors instead of one with two different fan blades like Dometic, and it’s a lot quieter.
I was also thinking of an Atwood ac that has 2motors but in talking with CW they said Dometic said they were phasing out that unit, and right now they haven’t got enough parts to make new units. Thanks again

[Platinum 1]

I forgot this unit uses410 Freon

[jjrbus]

Originally Posted by Platinum 1

Hi,
Yes he’s a HVAC guy, he’s my neighbor. Thank you for your information we’ll see if we have the space for the fil/dry I’m not sure, Dometic sure uses cheap materials.
At least on this unit. If it doesn’t work out then my replacement will be the recpro houghton unit, it’s has 2 motors instead of one with two different fan blades like Dometic, and it’s a lot quieter.
I was also thinking of an Atwood ac that has 2motors but in talking with CW they said Dometic said they were phasing out that unit, and right now they haven’t got enough parts to make new units. Thanks again

If I had the room for an inside unit I would have put a mini split in mine years ago!