Dometic RM2453 Ignition System: DSI vs Pilot Light Truth Revealed

The Quick Answer

Your 2001 Dometic RM 2453 refrigerator uses a standard single-stage gas valve with thermostat control, which is mechanically controlled rather than electronically controlled, which is why you're not seeing any wires going to the gas valve. The fact that your pilot light is burning very low and weak, getting blown out by wind, and only moving the gauge needle to dead center indicates you're only getting the pilot flame and the main burner isn't lighting at all. Common causes include a blocked or misaligned burner orifice, a dirty burner assembly, or insufficient gas pressure reaching the valve due to blockages in the gas line or flue system.

The valve operation works through a thermostat-controlled system that's built into the gas control valve assembly. When the cooling unit calls for more cooling, the thermostat signals for gas flow to create the main burner flame. Your thermocouple reading of over 20 millivolts is marginal - proper operation typically requires 25-35 millivolts minimum and confirms the pilot flame is hot enough to keep the safety valve open, but the weak flame you're describing suggests the main burner stage simply isn't engaging due to restricted gas flow or burner contamination.

What's Causing This

Common causes of your weak pilot flame and lack of main burner operation are typically related to restricted gas flow through the burner system. In these older Dometic absorption refrigerators, the gas travels through a small orifice that can easily become blocked with debris, spider webs, or corrosion buildup over the years. Since your camper is from 2001, it's likely been sitting unused for periods, which allows insects and debris to accumulate in the burner assembly.

The burner orifice on your RM 2453 is a precision-drilled hole that's designed to deliver a specific gas flow rate. Even a partial blockage can dramatically reduce the flame intensity. When you light the pilot and see it burning weakly, you're getting just enough gas to maintain combustion, but not enough to create the proper flame pattern that would heat the absorption unit effectively. The fact that it works fine on AC power confirms that your cooling unit itself is in good condition, which is excellent news.

Another common culprit in these older units is a blocked or restricted flue system. The flue baffle, which is located behind the burner assembly, can accumulate soot, debris, or even bird nests over time. This creates a back-pressure situation that prevents proper combustion air flow and can cause the flame to burn poorly. The flue baffle is designed to create proper draft and heat transfer, so any obstruction there will affect burner performance significantly.

Gas line restrictions are also possible, particularly in the small-diameter tubing that feeds the burner assembly. Over time, moisture can cause corrosion inside the gas lines, or debris from the propane tank can work its way down to the refrigerator. However, given that your thermocouple is generating good voltage, it's more likely that the restriction is right at the burner assembly itself rather than upstream in the gas supply system.

Tools You'll Need

For this repair, you'll need a basic set of hand tools and some specialized cleaning supplies. Start with a standard screwdriver set, particularly Phillips head screwdrivers for removing the lower access panel and burner assembly mounting screws. You'll also need appropriate wrenches for the gas line connections (see manufacturer specifications for exact sizes) and a small adjustable wrench for various fittings.

For cleaning the orifice and burner components, get a set of small wire brushes, including a brass brush specifically for gas components. Avoid steel brushes on the orifice as they can damage the precision opening. You'll also want compressed air in a can for blowing out debris, and a small dental pick or orifice cleaning wire set for carefully clearing the gas orifice without enlarging it.

SAFETY WARNING: Always shut off the propane supply at the tank before beginning any work on gas appliances. Allow the refrigerator to cool completely before starting repairs. Work in a well-ventilated area and never use open flames or smoking materials near gas components. Have a propane leak detection solution or soapy water mixture ready for testing all connections after reassembly. A multimeter will help you verify your thermocouple voltage both before and after the repair. Finally, have some high-temperature anti-seize compound available for reassembling threaded connections that will be exposed to heat.

Step-by-Step Fix

Begin by ensuring your propane supply is completely shut off at the tank and that the refrigerator has been off for at least an hour to cool down. Remove the lower outside access panel to expose the burner assembly. Note that full access to gas lines and burner removal may require accessing the refrigerator from behind, which could involve removing the refrigerator from its compartment depending on your installation. You'll see the gas valve, thermocouple, and burner tube arrangement. Take a photo of the setup before disassembly so you can reference the correct positioning later.

Disconnect the thermocouple from the gas valve by unscrewing the compression nut with the appropriate wrench size (see manufacturer specifications). Be gentle here, as overtightening during reassembly can damage the thermocouple. Next, disconnect the gas supply line to the burner assembly. There should be a union fitting that allows you to separate the burner tube from the main gas line. Again, take care not to over-torque these fittings.

With the gas connections loose, you can now remove the burner assembly itself. This typically involves removing two or three screws that hold the burner bracket to the refrigerator chassis. Once removed, you'll be able to access the burner orifice, which is usually a small brass fitting threaded into the burner tube. Remove this orifice carefully with the appropriate wrench, noting its orientation.

Clean the orifice using your dental pick or orifice cleaning wire, working from both directions to ensure the hole is completely clear. The opening should be perfectly round and smooth. Blow compressed air through it to remove any loosened debris. While you have the orifice out, this is also an excellent time to clean the entire burner tube with a bottle brush and compressed air.

Now address the flue system by removing the flue baffle, which is typically held in place by a couple of screws behind the burner assembly. Clean any soot or debris from the baffle and the flue tube. Check for any obstructions in the flue that extends up through the refrigerator compartment. A flashlight and small mirror can help you inspect the full length of the flue for blockages.

Inspect the burner assembly itself for any corrosion or damage. The burner should have evenly spaced holes along its length, and these should all be clear of obstructions. Use your small wire brush to clean around these holes, being careful not to damage them. Pay particular attention to the area where the pilot light flame impinges on the burner tube, as this area can accumulate debris over time.

Reassemble everything in reverse order, being careful to position the burner assembly exactly as it was originally. The alignment between the pilot flame and the main burner is critical for proper operation. Thread the orifice back into the burner tube with a small amount of high-temperature anti-seize compound, torquing to manufacturer specifications. Reconnect the gas line and thermocouple, ensuring all fittings are torqued to manufacturer specifications.

Before testing, spray all gas connections with your leak detection solution to verify there are no leaks. **CRITICAL SAFETY STEP:** Never skip this leak testing procedure as gas leaks can be extremely dangerous.

During leak testing - any gas leak can create a dangerous situation. Open the propane supply and test the system by lighting the pilot light. You should immediately notice a much stronger, bluer flame that's less susceptible to wind. The gauge needle should move well past center when the main burner lights, and you should hear the characteristic whoosh of the larger flame engaging.

When to Call a Pro

If you're uncomfortable working with gas connections or if the cleaning procedure doesn't resolve the weak flame issue, contact a certified RV technician. Also call a professional if you discover damaged gas lines, a faulty gas valve, or if you smell gas at any point during the repair process.

While this repair is well within the capabilities of most RV owners, there are several situations where professional help is warranted. If you discover that the gas valve itself is malfunctioning or leaking, this is not a DIY repair. Gas valves contain safety mechanisms that require proper testing equipment and expertise to service correctly. Similarly, if you find that the cooling unit itself has failed or is leaking ammonia, this requires professional refrigeration service.

Call a professional if you're uncomfortable working with gas appliances or if you don't have experience with propane systems. Gas leaks can be extremely dangerous, and improper repairs can create safety hazards. If you detect any gas odor during your work or if connections continue to leak after multiple attempts to seal them, shut off the gas supply immediately and consult a certified RV technician.

Another situation requiring professional help is if the flue system shows signs of significant corrosion or damage. The flue is critical for safe operation, as it carries combustion gases away from the RV interior. Any cracks, holes, or severe corrosion in the flue system must be properly repaired or replaced by someone with the appropriate expertise and parts access.

If your repair efforts don't resolve the weak flame issue, there may be more complex problems with the gas control valve or the cooling unit's internal components. Professional technicians have specialized gauges and diagnostic equipment that can pinpoint issues like incorrect gas pressures or failing thermostatic controls that aren't readily apparent to the home mechanic. In these cases, the diagnostic fee is usually worth it to avoid throwing parts at the problem unsuccessfully.