Hello fellow Dometic fridge owners,

Here are some hopefully helpful notes on the theory of propane operation in a Dometic Fridge. Understanding how it works helps get the sucker lit. So here goes...

Step 1: Ok so first you turn on the master gas valve on the propane tank. Gas now flows to the fridge. The gas stops at the fridge gas valve. Its positioned like this (-) when OFF.

Step 2: Now you turn the fridge gas valve to the ON position (|) . Gas now flows past the value thru the thermostat and stops. It stops at the ignition button because there is no flame in the fridge combustion chamber. This is a safty feature, gas must be burning in the combustion chamber for the gas to flow. A thermo-couple in the combustion chamber senses the flame and electrically tells the ignition button when its safe to pass gas (no pun intended I think). Ok, so you ask then how does gas ever flow then? Step 4 reveals that little secret, read on...

Step 3: Now we need oxygen to mix with gas so it can burn, so you stroke the air pump to get some oxygen down into the combustion chamber. Remember that chamber is sealed air-tight and its only inlet is 2 /12 feet up a small metal pipe to the van side vent (the air-tight seal is so carbon monoxide goes out the metal exhaust tube, not into the van interior). The higher you go in altitude, the more you have to pump to get oxygen down into the chamber (since the air is thinner).

Step 4: Now all is ready, we have oxygen and almost have gas. Here is where the ignition button comes in. You now press the ignition (or safty override) button. It physically opens allowing gas to flow even though there is no flame into the combustion chamber.

Step 5: Pressing in on the air pump causes a spark in the combustion chamber. If the gas lights you still have to hold in the ignition (safty override) button for a few seconds. This gives the thermo-couple time to sense the flame and tell the ignition (safty override) button its OK to pass gas (yup its that pun again).

Step 6: If the gas did not ignite you probably had too little oxygen. This can happen if you did not pump enough, or you held down the ignition (safty override) button too long. Holding the safty button in too long lets the gas push out the oxygen, or if the too rich gas mix is just right cause a small POP like explosion. In which case you have just pushed out all the oxygen you pumped in. So you go back to step 3 and try again.

One miscelanous note. That little metal tube at the bottom front of the fridge it there to let you drain out moisture out of the combustion chamber. Burning propane in a cold metal box (the combustion chamber) can cause some water to form. The tube lets you drain it out. And since its water the tube gets rusted over time.

Another miscelanous note. The propane feature is NOT maintenance free. Over time the combustion chamber and intake/exhaust tubes will need cleaning, the gas orifice in the chamber will need to be cleaned or replaced and the sight glass will need to be cleaned. Sooooo, sooner or later you will have to pull the fridge and do this.

I hope this helps you understand lighting the propane fridge. Once I understood how mine operated its worked perfectly.

Richard Angelini - 85 Westy