[BusNit]

I replaced blower motors, caps and starters last year. These things were nearly silent outside. The middle a/c was never that cold but it worked. When I was at Newell last October I asked them about it and they said they do not have parts or service for the Dometic units. Basically no parts on anything on my coach aside from the universal stuff like interior latches and *some* airbags but none that worked for my coach. As of now, I only have the rear bedroom a/c working but it too is on borrowed time for being 30 years old. Previous owner kept the coach at his covered RV parking facility in Phoenix (RV Hideaway) with the a/c's always running year round. They used the coach as a to and from transport from Oregon to AZ. The front A/C had a leak in the condenser which I had (thought I did anyway) fixed at a radiator shop for $85. A/C was leak free and held pressure up to the evening hours where the condenser sprung another leak somewhere in the fins. Compressor oil could be smelled in the air. It cooled well otherwise while it ran.

[ccjohnson]

When I had mine done, Newell had sourced the compressors from Johnstone Electric. They weren't 100 % identical, but were close enough to work well. The condenser fan motor was sourcrd from Granger and had to be modified. The shaft was too long and had to be cut off.

[Richard]

It is important to flood the internals with Nitrogen before soldering. If you don’t oxides form on the interior of the copper pipes, and then they can contaminate the refrigerant with flakes of the oxides. No matter if the system is capillary tube like the dometics or thermal expansion valve like the SCS units, the oxides stop up the expansion orifice. Tell tell signs of stopped up or non functioning expansion device are low LOW side and high HIGH side.

Did the radiator shop use SilFos (silver solder) or their normal 50/50 lead tin solder?

Post the dimensions of the coil, and how many rows of tubing it has. Maybe we can find you a new one.

[BusNit]

I did purge with nitrogen while soldering. I used the new process with Harris flux and StayBrite silver solder. I am sure my connections are fine but there's oil in the fins. I couldn't tell you what the shop used. Coil with metal flange is 18 x 12 and is 3 row. Bottom fitting is 3/16 OD and top is 1/4 OD  I inquired today at www.premierproducts.net as they have a 22k btu low profile 48v roof air. Honestly, that intrigues me since it would be super easy to wire it into my battery bank and the power consumption should be as good as a mini split while kicking out some good air. I called them with my questions and they will speak to their engineering department tomorrow. Even so, As I calm down from scrapping my existing units, I wouldn't mind gathering parts. If the bedroom one let go, I really would be up the hill without a paddle, boat, engine, bicycle... You name it! The rear one blows incredibly cold air. Front ones never were that great to begin with. I appreciate your help. That said, please enjoy your vacation. Marie canceled our trip up north. This bus ain't goin' anywhere this summer.

[Richard]

https://lrccoil.com/coils/?gclid=CjwKCAj...ioQAvD_BwE

https://emergentcoils.com/pages/condense...Y0QAvD_BwE

[Richard]

I have plenty of downtime in our journey up the Alaska Hiway. Rhonda didn’t want me to burn out driving, so I have been noodling your statement that you saw the same pressures with just 6 oz of refrigerant in the system.

That didn’t seem right to me, but there is one situation that may result in that, so I have to ask. When you were filling from the jug on the scale and watching the gauges, were you closing the low side knob to get pressure readings? The reason I ask, is that if you don’t close the low side knob, then the gauge is seeing the pressure of the refrigerant in the jug NOT the system, and furthermore the high side will be unusually high because the compressor is being flooded with vapor from the jug.

Do you recall? I am not trying to be a smart aleck, but you are doing an admirable job of learning AC basics. I have made every mistake in the book, and I am just trying to help you avoid my mistakes.

Sorry, couldn’t help on specific coils. I am in Canada, and google knows that. Meaning anything I find retail starts with Canadian suppliers.

[BusNit]

No Worries Richard! Seriously you need to not worry about this! Enjoy your trip.I was closing the valves to check on pressures but also knew not to exceed the 30 oz which I estimated based on lineset distance. The coil was all ratty when I brought it to the shop. Honestly I was hoping they could find a replacement but instead they wanted to try and fix it. I won’t tear out the units but let them ride along for now. Having said that, I also do not want to prolong my pain and think a roof air is the best solution. We did get a nice pull through site up north when they called but Marie had to cancel. They have nothing left for the summer. That’s just the story of my life. I got all excited about a new offering from RecPro on a just released 48v roof top unit with max draw of 1000 watts at 20k btu but after speaking to them they said it will not work on lithiums and especially not at the voltage they run which is in the 54v area.

[hypoxia]

I like Richards approach. I prefer repair over replace when possible and reasonable. The first thing I think of when rooftop units are mentioned is height. My current coach is tall enough that bridges and trees become a daily factor in the East. I normally do not use leak sealants but in your case I would before abandoning the system. New systems are not better, new refrigerants are not better, they are only being replaced due to EPA regulations. Energy Star appliances generally sacrifice reliability to get efficiency. ALL of the R410 units on my stick houses have about a 5 year life when coils start leaking.

That being said, you are the one with the wheels not turning and I can understand doing whatever it takes to get the wheels turning.