Old coldplate

[smurphny]

Little by little, am upgrading the systems on my old Alberg. The latest object to hit the dumpster was the old, heavy, 110v. refrigeration compressor. I am considering a small Isotherm 12v. cold plate unit, low amp draw being the critical factor. I don't need half the refrig. space that is built into the counter now and plan on insulating off about half the area which will leave maybe 2 cu. ft to cool. The existing box has a perfectly good, rugged looking cold plate which I have saved. I am wondering if this old cold plate can be used with a new small Danfoss/Isotherm compressor unit if I change it over to the new type connections and recharge. Would be nice to reuse this component if possible.

[Stu Jackson]

Most likely not because it used a different refrigerant. My local fridge guy told me a story about one of his clients who wanted to save $$ and mix a new compressor with an old evaporator (what you're calling the cold plate). After months of things not working, after the fridge guy recommended against it, the owner finally caved and did it right.

Besides, you'd be mixing two different manufacturers, even if the fittings matched.

Rather than blocking off half of your box, just insulate it properly and save as much space as you can. Once you have a new working unit, you'll find good uses for it.

Isotherm is a good unit.

Try looking up Kollman refrigeration: KollmannMarine Boat Refrigeration Specialist

[StormBay]

So long as the holding plate is properly evacuated and no dirt or debris has entered the system (even the smallest amount will cause huge headaches later on), there is no reason why you couldn't reuse it so long as it's the right size for your new unit. It shouldn't matter the old refrigerant type as long as you are only reusing the holding plate and you evacuate it properly first. All systems mix manufacturers: most small units use Danfoss compressors, the metering valves, evaporators, condensers, etc usually all come from different companies though. It is important, however, to make sure the holding plate is the correct size. To reuse it, you would need to bring it down to a 10 psig vacuum to make sure all traces of water and non-condensables are out of it before recharging. Unless the new system uses R-134a, you would also need to hire a HVAC technician to recharge it for you as you will not be able to buy any of the other refrigerants on your own. All said and done, probably not worth it especially since some of the newer units come with the components pre-charged and easy-to-use quick connect fittings.

[smurphny]

Thanks for the input. The refrigerant used in the new Isotherm units is R134a according to their specs. I guess the most important question is the size of the old unit. Don't know if I'd even try charging myself from automotive flit cans. Being that a cold plate that freezes and maintains a range of temperature as the on-off points for the compressor, I wonder if size really makes any difference. Wouldn't it just be the determining factor in the amount of time it takes to re-freeze? In that case, super-insulating the smaller space would seem to be the critical factor. All I really want to do is maintain a small space for a couple of cold beers which I find to be an essential piece of sailing gear after a long day on the water. Have thought about the small portable units but they are real power hogs.

[JimsCAL]

See no reason why you can't reuse the coldplate. The old unit probably used R-12 and materials are compatible with R-134a. Many systems were converted from R-12 to 134a in the early days of the refrigerant switch, and big issue was flushing the old oil out of the system because it was not compatible with the oil used with R-134a. That shouldn't be an issue since you can you coldplate can be easily cleaned inside. And yes, you would need to evacuate the system before charging. Requires a vacuum pump. A technician could do that for you.