Cold Plate Kaput

[sneuman]

Originally Posted by Alan Wheeler

Hi Scott, the compressor should be OK to use with the new R134a. It is the oil that is the important part. The oil is different to the oil used with R12.
The fault in the system could be one of several things. If the compressor is sealed (totaly electric) then it will be a gas loss due to possibly a leak in a copper tube or plate. If it is engine driven, it could be the same, but with the added possible of a seal failure around the compressor drive shaft. It doesn't have to be bad enough to see oil leaking, the gas can still escape. This is most common in situations where the unit does not get used regularly.
Another possible is the Drier. Once again due to the shaft seal, moisture can also get in. It only takes a little over time and enough eventually builds up to overcome the drier and then the Ice will block the system up.
Trying to find a leak is difficult. The first thing someone needs to find out is, does the system have gas. If it doesn't, then the second step is to introduce gas with a special dye. This is because finding a leak is not always simple and a refrigerant gas detector sometimes will not detect the tiny amount leaking. The dye leaves a mark at the leak that is seen with a UV light.
If a major overhaul is required, then you have to have a new drier installed, new gas, new oil and so on.
It is good to get to learn this stuff. It is probably the most common of breakdowns among a sailign community and the one leaset likely to find a knowledgable person on. Have that knowledge can help with making many friends. And maybe even a replenishment of the cruising kitty. I am still learning, but have gained a lot of knowledge from just a short time ago when I asked could I put LPG into my AC unit :-0

Thanks, Alan. This is very informative. It's electric only, so most probably a leak. Thanks to plais, too. I have been wondering about a full replacement, but don't really want to drop $1k or more right now. I have a dorm-sized refrigerator that I've been using, but wanted to get rid of it for space reasons. Maybe I'll use the cold plate box as an ice chest until I can figure out whether I should fix or replace.

[Pblais]

have been wondering about a full replacement, but don't really want to drop $1k or more right now. I

I can understand that. I did it 2 years ago, but sold the boat, now I'm looking at it again. Boy I hate seeing the same movie twice. At least this boat has a drain for the ice until I can get to it. If it is a basic cold machine the new ones are easier to install. if you want I would go see Richard Kollerman's site. He shows up around here once in a while too. Richard is pretty much it when it comes to 12 volt fridges.

[ozskip]

90% of leaks are at the tx valve if the system has one,caused by the cooling and cooling and heating of the pipe connections (expand and contract).The main differance with with compressors is r12 has mineral oil and r134a has sinthetic oil,tx valves are all so different as r134a reaches freezing at a lower back pressure and has a differant temp/pressure curve,controling the flow of refrigerant thus cooling and temps.If you use r134a in the r12 compressor all that will happen will it will adventurely fail one day and you will need to replace it .Greg

[senormechanico]

If you have lost the refrigerant charge and it's a water cooled condenser, make sure it isn't the culprit. That happened to our system. All the refrigerant went out with the cooling water. The leak detector went nuts at the thruhull.

Steve B.

[Alan Wheeler]

Boy I hate seeing the same movie twice.

Especially when the tickets cost 1K or more.