Yeah, I would go with condensation. I doubt there is any galvanic action going on.
Clean up the rusty area, prime it and paint it. Don't over think it!
08-14-2012 02:09 PM
08-14-2012 01:16 PM
Re: Fridge Compressor Corrosion - Stray Current?
To stabilize the casing, you'd want to sand, wire bursh, or etch it down to clean metal and then paint it up with several coats of "zinc" paint. Then you'd need to find out whether the problem is in the casing or if it is being chewed up by galvanic action.
You'll find some comprehensive articles online about testing for galvanic action, and methods to either isolate (probably not possible for you) or to add zincs outside and take other action to stop the damage. I'd suggest checking the rest of the boat, if there's galvanic damage to one item, there may be more damage to others.
08-14-2012 12:48 PM
Fridge Compressor Corrosion - Stray Current?
I have a 4 year old Danfoss BD35F compressor-based refrigeration system with a thru-hull SP cooling unit. On inspection, I've discovered that the compressor's casing is severely rusted with large, thick flakes of corroded metal falling off. Even though the environment under the galley sink is not pristine, that amount of corrosion seems unreasonable.
Is it possible that damage like this has been caused by stray current? If so, is there an easy way to prevent this? And given the large amount of damage done so far, can anyone recommend a treatment for the casing that would stop any further spread?