How do RV refrigerators work?

RV refrigerators heat up liquid ammonia, changing it to a vapor that absorbs heat as it expands. As the vapor condenses back into a liquid, it releases the heat it absorbed in the tubing inside your refrigerator to the outside of the refer on the back via the cooling tubes.  This heat is exhausted out your trailer via natural convection and is the reason your trailer has a lower and upper vent for the refer; some early trailers had the lower intake air only come from the interior cabinets.  The heat to initiate the cycle comes from a 110v heater coil or a small LP gas burner flame.

Why does my gas refrigerator works only on gas only, not electricity?

The cooling circuit of your refrigerator depends on a small section which must be kept hot in order to heat up the ammonia in the tubing. It can be heated either by a gas burner, or an electric resistance heater.  The two circuits are usually independent. The electric heat usually has a heating element and its own thermostatic control.

Make sure the heater element is inserted to its full length in its pocket or receptacle. If the electric heater is only partly inserted, the heat distribution will be incorrect.  Another possible failure is the heater element has burned out.  You can determine the failure by using a volt-ohm meter.  Modern heating elements can be adapted to fit in place of inoperative units.  If it is a modern refer, the most likely failure is the controller Circuit Board, which should be available from your nearest RV dealer.

Why does my gas refrigerator works on electric power only, not gas?

The cooling circuit of your refrigerator depends on a small section which must be kept hot in order to heat up the ammonia in the tubing.  It can be heated by a gas flame or by an electric resistance heater if so equipped. Usually these two systems are completely separate, and it sounds as though service is needed for the gas burner portion.  The usual causes are the burner orifice being plugged or damaged, or the gas control being plugged or needing adjustment. Plugged burner tips can be cleaned out with solvent and compressed air, and replacement burner tips are available from small appliance parts distributors.

Make sure the thermocouple flame sensor is in the flame path per the manual, and that all the fittings are tight.  The thermocouple compresses the air in the tubing as it is heated, opening a valve in the gas control it connects to.  If there is any air leakage, the valve will not open, so make sure the flame height and color is adjusted per the manual, and make sure that the vents are free and clear of blockage.  Also, make sure that there is LPG pressure at the control valve.