Fixing up some old marine refrigeration

Hi all,

I'm new to this forum, and I hope to solve a problem.

My wife and I own an old weekend type boat that had some custom made refrigeration aboard built by a company that no longer exists. It was gassed with R404A which has leaked out quite a while ago. I decided to pull the system to determine why the gas leaked and after quite a few swear words, I had the system removed and noticed several flares were not much past hand tight. There was probably the reason right away. I wasn't upset because I wanted to modernize the system anyway and perhaps convert it to R290.

I am not a licensed fridgie, but in my previous life, I was dealing in high pressure air and silver soldering pipework to handle 5000psi, so refrigeration pressures don't really phase me. I understand the fundamentals of refrigeration design, and, as far as I know, here in Australia, it's not illegal for me to work on a de-gassed system, and I only need a licensed person to re-gas (if I use a controlled gas again like 404A).

I have attached a diagram of the old system. Piping was generally 1/4" and 3/8". The cooling plates were eutechtic design. The plates all appear in good order. I intend to clean and flush them, and then pressure test to make sure everything is OK.

What I'd like to do is rebuild the system and use the Sanden compressor when the engine is running, and a 12V solar driven compressor for the rest. Adding in the complication of converting to R290, I want to know if what am trying to achieve is possible.

Thanks