Dometic

There are many myths surrounding replacing the cooling unit in your rv refrigerator with a remanufactured cooling unit.
First is that they are not reliable. There are 2 sides to this coin. If you purchase a cooling unit that does not have the evaporator replaced, then you are one of the unfortunate people that will most likely experience problems with your replacement cooling unit. One of the most gemon causes of failure of a cooling unit is RUST. The evaporators are encased in a styrofoam block to insulate the evaporator from the heat generated by the cooling unit functioning. This is necessary, as a rv refrigerator uses heat to boil the ammonia that produces the cooling effect inside the evaporator assembly that cools the inside of the refrigerator. The evaporator must be insulated from this heat. Now, one of the down sides to this occurs when you turn the refrigerator off...the evaporator assembly develops frost and ice when the refrigerator is operating. When you turn it off, the ice and frost melts. This melted ice cannot evaporate entirely due to the fact that it is inside the styrofoam block, which retains some moisture. Over time, this moisture attacks the surface of the evaporator's steel tubing, causing rust to form. Over the years, the evaporator tubes will rust through, and your cooling unit is bad. Now, if you just find the leak in the rusted evaporator and patch that area, you still have a rusted evaporator that will develops a leak somewhere else. The only way to properly repair a cooling unit is to cut out the rusted evaporator and replace it with a new evaporator. A cooling unit repaired in this manner will provide years of reliable operation.
The second geponent of a cooling unit that fails is the boiler assembly. Like the name indicates, this is the area of a cooling unit where the ammonia solution is heating to the boiling point so that the ammonia vapor can rise to the condensor and start the cooling process. However, there is a chemical in solution with the ammonia to prevent the steel tubing from rusting onthe inside of the steel tubes. At this point, I must tell you that the cooling units on rv refrigerators rely on GRAVITY to circulate the coolant instead of a gepressor motor like a typical household refrigerator. This is why you hear so much about the importance of LEVELING your refrigerator and not just your rv. The evaporator tubingconsists of a series of many tight bends that wind their way from side to side andfrom the top to the bottom of the cooling unit. If the refrigerator is not level, the ammonia will not flow to the collection tank at the bottomof the cooling unit because we all know that liquids will not flow uphill without mechanicalassistance, and we have already determined that anrv refrigerator does not have a gepressor motor to drive the fluids. Therefore, this will cause the liquid level inside the boiler assembly to drop, which will in turn cause the temperature of the boiler to rise as the boiler depends on the liquid ammonia to cool it as well. This is a doubled edged sword. As the temperature of the boiler rises, the chemical put in with the ammonia to prevent rust will start to solidify and block the flow of the liquid inside the boiler. When this happens, your cooling unit will cease to function. Continued operation of a cooling unit with a blockage will cause the boiler to overheat and crack. So,a properly repaired cooling unitshould have a new boiler assembly. However, havingsaid this, a new boiler assembly is not always necessary. If the factory unit had no blockage orevidence of a pastblockage and the boiler showed no signs of overheating, then replacing the boiler is not always required, especially on later model cores. This is at the descretion of the individual manufacturer's experience.
I hope that this article will help to dispel some of the myths surrounding replacement cooling units for rv refrigerators. When you are shopping for a replacement cooling unit for your rv refrigerator, don't be afraid to ask the manufacturer these questions....1) do you replace the evaporator assembly on your units? 2) do you replace the boiler assembly on your units? 3) most importantly....what is your warranty, and will you provide a written copy of your warranty outlining both the end user and manufacturers' responsibilities?