Refrigeration

[camaraderie]

I am thinking loss of coolant...slow leak somewhere.

[hellosailor]

"The fact that it shuts off when you turn your thermostat up to 5 rules out a relay in my opinion, after all, it did shut off."
Good point!

That does sound more like "I just can't keep up" which could be slight refrigerant loss, etc. One quick way to test for that would be to load in some block ice or dry ice to provide extra cooling, and then try again with the thermostat set down cold. If it cycles and works properly that way--then the gas loss would be very likely. Or, more/new insulation, but either way you'd need to check the gas charge or check for leakage. The simplest way to test for gas leakage is to spray all the fittings with bubble-soap, and then look to see if anything is blowing bubbles. That would only show a fairly large leak though. A "sniffer", for less than $100 used from eBay or a pawn shop, is way more sensitive (will pick up leaks that are less than 1 oz. of refrigerant per year) but costs a bit more up front, and requires some patience to work with. An essential tool for DIY refrigeration/AC maintenance though.

[recycle]

When I bought the boat last July I had the coolant gas checked and they did add a little to it. He also checked for leaks and found none. It does go below 38 and will keep going. It gets very cold in there and everyone keeps stopping by because I guess I have the coldest beer. It will shut off when I turn the knob past 0 and I feel a click. I think this is the off position.

I'm going to take a look at the relay if I can find it and possibly the thermostat.

I'm in slip right now but will be on my mooring soon so the power drain will become an issue.

Thanks for all the help. This is our first boat with referigeration.

Tartan 3800
Luna
East Greenwich RI

[hellosailor]

FWIW: "He also checked for leaks and found none. " That doesn't mean there are no leaks, they can be difficult to find, even when the tech is doing things properly. Leaks are something like poker: The game is deceptively simple.

[JiffyLube]

Originally Posted by hellosailor

When cars "all" had ignition points and replacing them was a part of every tuneup (and they cost something like 10 gallons of gas? 20?) it was routine to polish the points that way, to prevent them from sticking.

And to get more mileage out of the points before you had to buy new ones...I know because I still have a truck that has points...lol

[JiffyLube]

I second the idea of checking out Kohlman's website KollmannMarine Boat Refrigeration Specialist . I think I read about your problem in their forum, while I was trying to solve my situation.

[ehmanta]

Could also possibly be over-charged if the lines are freezing up.
This passage is from Frigoboat:
"Too much refrigerant in the system will result in liquid still evaporating back to a gas past the end of the evaporator and inside the tubing going back to the compressor. This means that there is still some of the refrigeration process going on inside the tubing and there will be a build-up of frost or ice on the exposed section. If additional insulation has been added, it may be concealing this symptom and should be removed. The evaporator may appear and sound normal, but will be at a higher temperature than desired, resulting in longer than expected run times."


These links could help:
RParts: Refrigeration Parts Solution
Design Your System

[recycle]

Thanks for all the help. I'll do some more investigation this weekend. Should be fun. At least it works and keeps everything cold.

Tartan 3800
Luna

[chucklesR]

Cool, literally. Think propane. It's cheaper per 'erg' than any other system.

[erps]

Cool, literally. Think propane. It's cheaper per 'erg' than any other system.

Why do you suppose they're not more widely used on boats?