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How an RV Refrigerator Works

Gas and electric absorption fridges, 12 volt compressor fridges, how long they take to cool and how to keep food cold on the road.

Two kinds of fridge

Most RVs built before a few years ago have an absorption fridge from Dometic or Norcold. It has no compressor. Heat from a propane flame or an electric element moves ammonia through pipes on the back, and that pulls heat out of the box. It is quiet and runs on propane with no power drain.

Many newer rigs have a 12 volt compressor fridge, like a small home fridge. It cools fast and does not care about being level. It runs off the batteries, so it needs solar, shore power or driving to keep them charged.

Getting it cold

Park as level as you can. An absorption fridge that sits far off level for hours can damage its cooling unit.
Turn it on the day before you load it. An absorption fridge can take eight hours or more to get cold.
Load it with food that is already cold. Warm food slows it down a lot.
Do not pack it tight. Air has to move around the fins inside.
Keep the door shut. Plan what you need before you open it.

On the road

Many people run the fridge on propane while they drive. Turn it off before you pull up to a gas pump, and turn off any other gas appliance too. A pilot flame near fuel vapor is a fire risk.

A full, cold fridge stays cold for hours with the door shut. If you do not want to drive with propane on, that is fine for most day trips.

Signs something is wrong

An absorption fridge that works on electric but not gas, or the other way around, usually has a simple fault. Check the propane supply or the breaker and fuse first.

A smell of ammonia or yellow powder on the back of the fridge means the cooling unit has leaked. Turn the fridge off, open the windows and do not use it until it has been fixed.

When to call a shop

Call a shop for an ammonia smell, yellow residue, a fridge that will not cool on either power source, or a flame that will not stay lit. Many fridges have had recalls, so have your model number ready.

The maker's own manuals

These guides cover how most RVs work. Your own rig may differ, so check the manual for your make and model.

Dometic · Fridges, air conditioners and awnings
Thetford and Norcold · Norcold fridges and Thetford toilets
Every maker we link to

Renting from us? Call or text 909-259-RVDR before you try a fix. We would rather talk you through it than have you guess, and it is free.

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