Frostmate

[tm3]

Ahoy,
Does anyone out there have an Alder Barbour FM790 Frost Mate refrigeration unit on board or have knowledge of that particular unut?
tm3

[RLK]

What is your problem? Describe in detail.

[tm3]

My Frostmate works great normally except when I run my engine for an extended period of time. The compressor will shut down for varying periods of time from 10 minutes to 3+ hours. The raw water pump continues working and the Refrig. Ampmeter indicates the compressor tries to kick on. Eventually it does. We began using the refrig. in earnst this season since we are now live-aboards. I did have some refrigerent put in and it did help lower the temp. quicker and lower.
According to the manual left on board by the previous owner the compressor can be mounted anywhere since outside heat will not effect it and cites the engine compartment as okay. It is mounted in the engine compartment approx. 5'' from the engine and I do have a large engine compartment. Even though the manual says heat will not effect the unit I have a feeling that may not be factual.
All wiring appears fine and thermostate appears in good working order.
If more info. is needed let me know.
Thanks
Ray

[GordMay]

From R.L. (Richard) Kollmann
Author of DIY Refrigeration & 12-24 Volt Refrigeration

Sorry for the delay in answering I have been busy answering questions on the boat owners forum and I have one more week to go. http://www.sailboatowners.com/forums/menunew.tpl?fno=37

You say it is a Alder Barbour FM790 Frost Mate and it is water cooled therefore it must be a Super Cold Machine (SCM), air and water cooled. The older model SCM used a brush type compressor the newer models use a Danfoss BD compressor with a control module box connected to the compressor. In either unit the compressor is overheating.
Overheating of these units means there is a lack of cool air flow through the fan condenser. If the cooling air through the condenser is warmer than 90̊ F. efficiency begins to decrease unless the seawater temperature is below 75̊ F . For this unit to shut down on overheat I believe the air cooling coil is blocked with dirt. They must be cleaned at least ounce a year on live aboard boats. The SCM can not be cooled by seawater alone, it will always require the fan condenser for adequate cooling.
_________________

[tm3]

You cite an air cooling coil. Is that inside the sealed compressor?
Can I clean it and if so how or should I leave that up to a qualifed person?
You also cite a fan condensor. I don''t have one that I know of. Where would that be located and how would that work?
Thanks
Ray

[GordMay]

Richard’s references to Fan Condenser, and cooling coil (same thing) both should have read Condenser & Fan.
The Condenser is the small finned “radiator”, separate from the compressor motor. A small fan (like a computer fan with a shroud around it) blows air through the condenser coil fins.
The Condenser fins must be cleaned - use a small vacuum and/or a condenser comb (available from AC/Refrig shops). You may have to remove the shroud to get good access to the condenser fins, but it''s a very simple DIY job.
HTH
Gord

BTW: I was just passing on Richard Kollmann’s advice. He has an excellent Refrigeration web-site with lot’s of tips and info’, and a forum where he answers questions:
Website: http://www.kollmann-marine.com
Forum: http://www.kollmann-marine.com/phpBB/

[tm3]

Thanks for all the info.
I''ll go to the cited web site and see what info. is available.
Thanks Again