I apologize to all my customers who I have told that their refrigerators shouldn’t ice over. In a case of repeating mis-information, I was told that early in my career (1990s) and believed it until researching for this article, that modern boat refrigerators should not ice over in normal use.
In reality the common boat DC refrigeration units do ice over in normal service.
I spoke with two San Diego refrigeration experts, Mr. Gary Flemming and Mr. Thomas Gillette. They educated me, finally, that the common AC / DC refrigeration units such as Norcold and Nova Kool will ice over in normal service. The interval between defrosting cycles is usually 1 – 2 months. They suggest defrosting when the ice reaches ¼” thickness.
AC refrigeration units such as Sub Zero or U-line have self-defrosting features. The AC electrical supply supports the heating element required for defrosting.
The most common contributing cause to icing over of refrigeration units is bad gaskets or other sources of warm air such as drain holes in built in refrigeration units. If your refrigerator is icing over faster than your neighbors, perhaps it needs a new gasket.
The proper way to defrost a refrigerator is to open the door and let the heat melt the ice or quicken the process with a hair dryer. Catch the water in a container and/or use a towel. Use of a knife or an ice pick is risky as puncturing refrigeration components is costly or potentially fatal to the refrigeration unit. Dry everything before you put it back in the refrigerator, this will reduce the moisture inside the unit and extend the time period until the next de-icing.
AC / DC refrigeration units are equipped with a DC compressor, and an electrical converter which converts the AC source to DC for the compressor. These units do not have AC and DC compressors. They will run on both power sources but will not self defrost.
Iced over refrigeration units lose their ability to cool and become warmer as the ice thickens. So check that refer unit, if it looks like one of these photos defrost it and make sure it is ready for the summer holidays.
We have attached a page from Norcold with some tips.
Happy July 4th!