Dometic cooling units are built to last and are popular for RV fridges due to their durability and ability to keep food cold on the road. However, like all appliances they can have problems and you might need to do some refrigerator troubleshooting and repairs. Whether your fridge is running on electric or propane power, always disconnect the power source before you open access panels or remove parts. Also, make sure that the fridge isn’t leaking and that it isn’t too full so that air can circulate. Finally, wear rubber gloves and rubber soled shoes when working with or near electrical components to avoid shock and keep water and other liquids away from your work area.
Most Dometic and Norcold refrigerators use gas absorption refrigeration. This means that heat boils an ammonia and water mixture inside the boiler, turning it into a gas which then rises through a coil system until it hits the evaporator where it condenses back to a liquid. This process cools the fridge because the vapor absorbs and disperses the ambient temperatures of the RV refrigerator’s interior.
The Fridge Defend monitors the “normal” boiler temperatures of your Dometic or Norcold fridge and turns off the heater when it starts to overheat. This prevents the evaporator tube from cracking under thermal stress which can lead to cooling failure or even an RV fridge fire.
A thermistor clips onto the fins of the refrigeration compressor/condenser. It communicates temperature changes to the refrigeration circuit board by changing resistance when it reaches different temperatures. The thermistor is very important to the refrigerator’s operation, and a faulty thermistor can cause over-cooling. A thermistor with high resistance is usually a sign of a bad thermistor.
It is recommended to perform a dry run installation of the fridge cooling unit into the refrigerator cabinet to ensure that the evaporator foam pack fits down into the pocket correctly. This also gives you a chance to trim any insulation or evaporator foam that is interfering with a good fit.
If your Dometic fridge doesn’t produce a cooling effect, you may need to check the air pressure inside the refrigerator cabinet. A low pressure will reduce the fridge’s cooling efficiency, and this can be caused by a number of things, such as over-filling the fridge, or dirt and grime inside the vent.
Another problem is a broken evaporator seal. If this is the case, you will need to replace the evaporator foam pack.
A thermocouple can be temperamental, so it’s wise to carry a spare one with you on your trips. This is especially true if you are traveling off-road or in extreme temperatures. It is also a good idea to have a thermistor tester available to test the integrity of your thermistor.