An RV refrigerator that works on shore power but will not cool on propane is one of the most common calls we get, and one of the most commonly misdiagnosed. Owners usually assume the fridge has failed. Most of the time it has not.
Why it behaves this way
An absorption refrigerator has no compressor. It works by heating a solution and letting it circulate, and it does not care whether that heat comes from an electric element or a propane flame. So if it cools on electric and not on gas, the cooling unit itself is almost certainly fine. The problem is on the gas side.
That is good news, because a failed cooling unit is one of the more expensive repairs on an RV and almost everything else on that list is not.
The usual causes, roughly in order
Low or empty propane. Obvious, and worth ruling out first. Gauges on RV bottles are not always honest.
Air in the line. If the bottle has run dry or been changed, the line needs purging. Run a stove burner for a minute and try the fridge again.
A dirty burner or orifice. This is the single most common cause. The orifice is a tiny brass jet and it takes very little dust, rust or spider web to disrupt the flame. Mud daubers in particular love the burner tube, and they are a genuine and well known problem on RVs left standing.
A weak or dirty thermocouple. The safety device that proves the flame is lit. If it cannot sense the flame properly the gas valve shuts within seconds, which shows up as the fridge lighting and then going out again.
Regulator problems. A regulator that has aged or been contaminated may deliver enough pressure for a stove and not enough for a fridge, because the fridge orifice is far smaller and far less forgiving.
Not level. Absorption fridges need to be reasonably level to circulate. Parked on a slope for a long period, they stop cooling and in bad cases can be permanently damaged.
What you can check yourself
Confirm you have gas and that other appliances run. Purge the line. Check the rig is level. Look at the flame if you can access it safely, because it should be steady and blue. Yellow, lifting or lazy means the burner needs cleaning.
Where to stop
Stop at anything that involves opening the gas system. Orifices, regulators, valves and the burner assembly are not a place to improvise. A propane leak in a confined space is a different order of problem from a warm fridge, and the parts are small, specific and easy to damage.
If you smell gas at any point, shut the bottle off and do not try to light anything.
What we do
Our propane system repair is a test of the whole system rather than a look at the part that failed. Pressure at the regulator, a leak test on the lines, and the burner and orifice cleaned or replaced properly. If the fault turns out to be on the electrical side instead, that is electrical repair.
If your fridge has stopped cooling on gas, ring us on 346 708 4612 and describe what it does. It is usually a cheap fix and it is worth knowing which one before you start replacing anything.