Dometic User Manual Caution: “Do not use: A knife or an ice pick, or other sharp tools to remove frost from the freezer shelves. It can create a leak in the ammonia system. A hot air blower. Permanent damage could result from warping the metal or plastic parts.” We use neither sharp tools nor a hot air blower and yet easily and routinely defrost our Dometic RM2551 RV refrigerator (5 cu. ft.) in less than 30 minutes.
Frost and ice buildup on the cooling fins reduces the cooling efficiency of the refrigerator. As seen below, our refrigerator is overdue for defrosting!
I usually defrost our refrigerator about every two months depending on outside temperature and humidity conditions. I like to start a trip with the cooling fins clear of most of the frost to make sure the refrigerator maintains safe temperatures for food (40° F or less). We use our RV refrigerator full time (it acts as a supplemental refrigerator when at home) and it always has food in it, so it is important to be able to do the defrosting quickly, to prevent food spoilage and to shorten the recovery time to get adequately cold again.
Once I determine that the refrigerator needs defrosting, I choose a warm day and gather five tools: a cooler, electric fan, large Tupperware lid, extra long chopstick, and a washcloth.
One of the benefits of our 23′ Airstream Safari trailer is that the large lobster sink/counter is directly across from the refrigerator, which provides a handy location for the fan to direct warm air directly into the freezer/refrigerator compartments.
I then turn off the refrigerator, fully open the door and place most food items in the nearby cooler. (I leave most condiments and other food items in the door in place.)
As you may have noticed, our refrigerator’s white thermistor probe wire is not in its OEM plastic holder on the far right fin where it normally is moved up and down to regulate the temperature (See Adjusting the Thermistor to Improve Cooling*). Refrigerator thermistors are NTC (Negative Temperature Coefficient) thermistors* and resistance decreases as the temperature increases. The higher the position on the fin, the warmer the thermistor will be and the refrigerator will run longer and become colder. But our probe wire is short and does not allow it to be moved high enough on the fin to obtain the proper refrigerator coldness. So I found that by removing it from its holder and moving it away and down from the fins, I can adjust and maintain the proper refrigerator coldness (which for us is usually 36-37 ° F and monitored by our AcuRite Wireless Digital Thermometer).
I use a condiment bottle to prop open the freezer door (Thai sweet chili sauce* works well) and place the frozen items in the cooler.
A closer look at the tools is seen above: an inverted Tupperware lid to collect melting ice chunks, an extra long chopstick* (17.7″ bamboo chopstick for hot pot and wok cooking) to gently loosen ice chunks, and a white washcloth to wipe clean and dry the refrigerator. (Note: we have greatly reduced our use of paper towels by purchasing a 24-pack of white reusable washcloths from Costco and also available at Amazon.com.)
Tip: This set of 4 flexible silicone ice cube trays from Target works wonderfully for us. It makes ice cubes quickly and takes up less space than traditional ice cube trays. It helps keep other food items cool in the cooler when defrosting and it helps decrease the refrigerator’s recovery time after defrosting.
Packages of fish balls, jiao zi (dumplings),* and pesto are seen on the left.)
The fan is then turned on and defrosting will take about 20 minutes!
As ice begins to melt, water drips down and is collected in the condensation drain pan and flows through its bottom hole into the Dometic white drain pipe with cup, which connects with the drainage tubing on the backside of the refrigerator.
Our OEM drainage tubing had become brittle and we replaced it with Shields Rubber Series 162 Polyester Reinforced Clear PVC Tubing, 1/2″ ID (inside diameter). I chose this tubing over the clear vinyl tubing because it is reinforced, can tolerate hot water (or being in a hot space such as near the boiler tube), is more flexible and is slightly less expensive than their clear vinyl tubing.
The chopstick is then used to gently nudge the melting ice sections forward and off the fins and collected in the Tupperware lid and deposited by nearby plants.
The washcloth is then used to remove excess water and wipe down the refrigerator’s insides and door seals, which completes the defrosting process in 30 minutes or less!
*This is a link to a YouTube video.