Good Sam Platinum and Platinum+ Roadside Assistance members have access to operational and technical assistance from certified RV technicians, which includes information on diagnosing and repairing failed RV components. This information is provided by certified RV technician JD Shirey.

A non-working RV refrigerator can not only cause a headache, but can seriously interrupt your travels. In the heat of the summer, a malfunctioning RV refrigerator will spoil food, deprive you of cold drinks and even pose a safety hazard depending on the issue.

Because power failure is a common source of RV refrigerator failure, let’s begin by discussing the principles of operation for the common dual-source refrigerator.

How does your RV refrigerator work?

Your RV refrigerator is designed to operate on one of two available power sources: LP gas (propane) or 120 VAC (shore power).

Most refrigerators have an automatic feature that selects the most economical power source. For instance, if shore power is available, then the unit will choose it over propane. However, you can also manually select your preferred power source. You will note that we said “most economical,” rather than most efficient, which will be further explained later in this article.

How is your RV refrigerator different from your home refrigerator?

The gas/electric refrigerator is unique in operation because it operates on the absorption principle, unlike your home refrigerator that is equipped with a refrigeration pump (compressor). The cooling unit is a maze of tubing that utilizes the phase change of ammonia, hydrogen, water and sodium chromate to remove the heat from inside the refrigerator food storage cabinet. As the ammonia is heated by either the propane burner or the electric heating element, it liquefies and flows into the hydrogen gas in the evaporator (freezer) where it evaporates rapidly causing the cooling effect.

The cooling unit must be level in order to operate properly. If the cooling unit is not close to level then the ammonia will not flow at the correct rate to allow the proper gas-to-liquid phase change to occur. The system also relies on gravity for proper circulation, which is why your refrigerator must be within +-2 degrees of level or approximately half a bubble off.

At this point we should note that the cooling unit is sealed and cannot be serviced. You cannot recharge it like an automotive air conditioner and there are no serviceable components; it is a sealed and welded together assembly. This is to prevent leaks normally associated with fittings, connections and o-ring seals. As a result the cooling unit must be replaced as an assembly.

Why won't my RV refrigerator start on electric?

One of the most common concerns RV tech hot line receives here at Good Sam Roadside Assistance is “I just tried to start my refrigerator on electric and nothing happens.” One of the most common causes of poor operation is low voltage.

As indicated earlier electric operation is the most economical but not always the most efficient. During the summer vacation season many RV parks are filled to near capacity and air conditioners are running wide open resulting in a high demand for power. For this reason, voltage at the hookup is lower than normal dramatically effecting on refrigerator operation.

When running on electric, the RV refrigerator requires a specific amount of heat in order to stimulate the ammonia to flow in the cooling unit, which requires a specific amount of voltage. Most are designed to operate within + or - 10% or 108 to 132 volts assuming a 120-volt source. Mathematically, at 108 volts you are getting only 90% of the needed electricity required to the heating element.

It’s not uncommon for voltages to drop as low as 90 volts during peak hours in RV parks, and at this voltage your refrigerator cannot operate as designed and will not cool properly. This is why most refrigerators operate better on LP gas; it offers a more consistent heat source and doesn’t fluctuate like electricity. In short, if you notice poor performance then try switching to LP, and if this solves the problem then you know you may be suffering from low available voltage.

Why is my RV refrigerator not working on gas or electric?

Let’s say your refrigerator does not work on gas or electric. What can you do? What are the possibilities?

• Check that there are no obstructions blocking air flow around the interior and exterior of the unit. Do not store towels or other items between the refrigerator and surrounding cabinet or enclosure. Ensure adequate clearance between the exterior vent and other outside items, and don’t turn your refrigerator on with the RV covered.
• Check your LP gas level and ensure the tank valve is on.
• Check the control panel for operation. Check to see if the interior light illuminates with the door open. The control panel relies on 12-volt DC power, if it does not illuminate you may have a blown fuse or low coach battery power.
• Check all interior circuit breakers in the power distribution panel.
• Check your control panel on your refrigerator for fault /diagnostic codes, which is a great tool to use in identifying your current problems. Both of the main RV refrigerator manufactures (Norcold and Dometic) display fault and diagnostic codes on their control panels when the operating systems aren’t functioning correctly.

Both manufactures have available online fault/diagnostic codes and troubleshooting techniques for the do-it-yourselfer, which can be found on their websites. To use the respective websites’ resources, you will need to know the model of your refrigerator (found on the inside of your refrigerator door or in your owner’s manuals that came with your RV).

Also check the recalls that are available because you may find that your problem is not so unique.

Disclaimer: All refrigeration repairs should be done by a qualified repair facility. RV refrigeration deals with AC/DC Electricity, as well as LP Gas, and can be dangerous to the novice. The information provided in this article is intended to give you product information and a checklist of things you can do safely prior to contacting a service facility for repairs.