RV and Home refrigerators differ not only in size but also in dynamics they employ to chill. Home refrigerators use an electric pump or compressor to pressurize Freon gas. . RV refrigerator uses heat of a gas flame or electric heater to boil and process the ammonia in the system called absorption cooling. Although the cooling process of rv refrigerators does not employ moving parts, movement of the air and gas is a major requirement for the rv refrigerator to work. Three movements required are;
1. Movement of air behind the refer
2. Movement of air in the refer
3. Movement of ammonia liquids and gas in the coils
Movement of Air behind the refrigerator - the coils behind the refrigerator are designed to work passively through convection of air heated by the gas flame at the bottom . Hot air rises and exits out the top vent . The path draws fresh air thru the lower vent. When the outside air is hot and the walls of the motorhome hotter this passive convection is slowed down and the stream of air stops. It is sometimes necessary to install a fan at the top vent to draw air up and out. Directing a fan on the coil has no effect as that may just stir up the hot air. Top vent fans are also useful when driving if wind in the vent pressurizes the compartment obstructing airflow.
Movement of air in the refer - when you put warm objects in the refer, they get cold by loosing heat to the cold air that drops down the compartment from the chilling surface. The dropping cold air pushes warm air up . A refer that is packed solid with product has no path way for this necessary air convection Internal circulation fans help cool items down quicker but are not necessary unless you overstock the refer.
Movement of Ammonia - when parked it is necessary to set the rv level front to back to keep the coil lines level. The ammonia that passes through and up the coil then drops down the return pass cannot overcome the effort to push uphill through every line. When the ammonia doesn't move through the lines the flame cooks the solution at the boiler and blocks the entire process. While traveling the sloshing around and road vibrations help overcome unlevel operation.
A good website with helpful information and a forum for repair questions is RV Mobil
