Dear Boat Doctor,

The refrigerator on my boat keeps getting a lot of ice build-up, and both the top and front doors are sweating around the openings. A friend of mine told me I need to clean the cooling coils, but that doesn’t seem like the problem. 

Sarah Dongell
Lynn, Massachusetts

Dear Sarah,

Your cooling coils are just fine and the compressor is working great, maybe even too well. What you are experiencing is ambient air infiltration: Warm cabin air is getting into the refrigeration box or cold air is getting out, depending on your point of view. As the warm moist air gets into the box, it condenses on the cold plate and freezes into ice.

Take a look at the gaskets on the door and replace them if you need to. If they look OK, you can try for some additional internal insulation. The foil-covered bubble wrap insulation material available at home improvement stores works really well.

Making sure the cooling coils on your compressor are dust free will help the compressor run more efficiently, but will not help with the problem you are experiencing.