Cold plate refrigeration on Grand Banks

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Feb 11, 2018
Vessel Name
Vessel Make
Grand Banks 49MY
I have a 1985 Grand Banks 49MY with cold plate refrigeration. Although 33 years old and still working, I would like to purchase a remanufactured compressor unit and keep the R12. Does anyone have any leads on who might rebuild the old systems? I can provide serial numbers for the unit I have. My boat has a large freezer aft and two refrigerators (stacked) in the galley.
Unfortunately Sea Frost sells water cooled systems and mine is air cooled

I just replaced the 120v Grunert cold plate freezer system on my 42 Grand Banks. I had water cooled before so I went with a water/ air system. Sea Frost sells air, water, and air/water cooled. New system can get significantly colder and keeps ice (and ice cream) from melting. It also has low power demand.
The cold plates were purchased (usually Dole) , as was the compressor and the rest of the gear by Grunert..

New compressors are seldom more efficient , but if yours dies a company like harry alter , or your local commercial refrigeration supply will have the newest version of the size compressor you require.

R-12 is expensive , the replacement using both propane and butane is about 15% more efficient , and cheap and available ,

BUT it is flammable. In England with the very indifferent labor there have been some leaks , but boats are usually serviced by pros.

Use it with a bilge sniffer (as a propane stove would use) if you worry.

The temperature the plate requires is about 10deg below the eutetic freeze/ melt temp.

This will be set by the TX valve.

Catalog - Harry Alter Co.

Catalog - Harry Alter Co.

Since 1933 – when we were the first wholesaler of refrigeration supplies in the U.S. – we've supplied customers with a comprehensive selection of wholesale ...
I replaced the Grunert cold plate in my freezer with a Frigoboat evaporator coil. The Frigoboat uses a through-hull puck for the condenser, so there is no need for a pump, the compressor provides all the motive force to facilitate the circulation of the refrigerant (134a). It uses a 12V Danfoss compressor, the line sets are all pre-charged and the whole conversion can be a DIY project if you have the inclination and a skillset that you're comfortable with cutting holes and mounting the gear. Because the lines are pre-charged, the connections do not require specific refrigeration skills, only good mechanical skills in making up the connections.

IMO as a retired HVAC guy, the cold plate is archaic technology. The compressor section is HUGE compared to the Frigoboat, you must run a 115V ~15A hog for a few hours a day, there's a pump involved... now running the compressor may not be an issue depending on your generator use, but consider that the Frigoboat system only uses about 3-5A DC- it can easily be powered by solar and doesn't add a huge amp hour load on your house bank. Downside is it can't be run on the hard, it'll lunch the compressor. (I'm embarrassed that I forgot to turn mine off when the boat was hauled- it's an oversight you'll only pull once!) I just can't see investing in 30+ yr old equipment. If the compressor suffers a running burnout, having a spare won't be much help, since contaminants (read:acid) will be circulated throughout the system. Cleanup is costly, and most techs won't do it properly, but will instead install a dryer as a stop-gap to get their work past a warranty period. It'll work for a while until the acid does its damage on the replacement compressor and the rest of the system. If the plate leaks, eutectic in the refrigerant will trash the system. If the holding plate has any bulges, it's suspect. Even if you do replace the compressor and refrigerant conversion, it's a risky investment in equipment that is essentially at end-of-life.


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