Maintenance- Cleaning a Norcold Burner
After Mark Polk’s great post on getting the most from your RV refrigerator, I though I would get my hands dirty a bit, and give some fairly simple hands on instructions on cleaning the burner of a mid to late 1990’s Norcold. While often the burner can be cleaned with either compressed air or a vacuum, if maintenance has been put off, sometimes you need to take the burner out for a good cleaning. Symptoms of needing a burner cleaning include poor/no performance on LP gas, and failure of the flame to ignite and stay burning.
A few safety tips before we begin- even though this is a reasonably simple procedure, you are working with the LP gas system, and proper safety precautions need to be taken- among them turn the LP supply off, disconnect the power to the refrigerator, don’t smoke while working….in other words, don’t blow yourself up (and if you do, don’t blame me or RV.Net!)
Ready? Let’s go…
The model I am using is a Norcold 662, but the procedure will be the same for many other models. Most Norcold models built since the early 1980’s use a “horizontal” burner. Norcold did change the design a few years ago- while the burner looks the same, the orifice assembly was changed to a new design- the main difference being that the new designs use a flare connection instead of a ferrule/ copper gasket.
Before you can clean the burner, you need to get to it- first, I remove the condensation drain cup, next, remove the sheet metal cover which hides the burner assembly. Now you can see the burner as well as is possible. Looking at this burner, we can see that it is producing a very “lazy” flame, not the hard blue flame that is needed (on most Norcold models, you can hear a slight roar when the flame is burning correctly).
Now would be the time to try blowing the burner out with compressed air, or vacuuming it out with a shop vacuum. If that restores the good flame- great! put it all back together, and enjoy the beverage of your choice!
But… if that doesn’t fix it, we will need to remove the burner and orifice and give them a good cleaning. Making certain the LP and power (both 12 and 120 volt) are turned off, we will remove the nut attaching the LP tuning to the burner. Note that the tubing is soft aluminum and the nut is brass, so you need to watch carefully when loosening the nut to make sure the nut breaks loose from the tubing and you do not twist the tubing (voice of experience speaking). You may need a short spray of your favorite lubricant to help it break loose.
Once the nut is loose, you can pull the tubing back a bit allowing access to remove the burner. The burner is held in by a single phillips head machine screw- once you have that removed, the burner will pull straight out.
Sometimes when the tubing is pulled out, the copper gasket and orifice will stay on the tubing, many times it will stay in the burner- in the left hand photo, you can see the gasket and orifice still in the burner. This copper gasket is very important and is a replacement item- you must install a new one on this type of Norcold burner when you disassemble it like this.
The good news is that an orifice and gasket are only about $5, cheap enough that I never even clean the orifice on these models, I just replace it. Newer Norcold models use a flair fitting and brass orifice so the gasket is not used.
14 years is not too bad for a steel burner in a hostile environment, and at around $30, it just makes sense to go ahead and put in new.
If you have access to compressed air, now would be a good time to blow out the flue tube- the tube that the flame goes in to. Just be careful to cover the open end of the LP tubing so you do not blow dirt in to it.
Reassembly is just the reverse of disassembly- replace the burner, put the new gasket and orifice on the end of the tubing, and tighten the nut on the tubing in to the burner. I usually put a very small dab of anti-seize compund on the tubing under where the brass nut rests, simply to make disassembly easier the next time- but only use enough for a thin coating on the tubing and keep it away from the ferrule. We can now turn the LP and power back on, turn the refrigerator to LP operation, and leak test the connection using an approved leak testing solution (yes, soapy water can work, but the soap must not contain ammonia, which makes brass brittle- leak solution is cheap and easily available.
After testing, we can shut the refrigerator off and check the spark gap between the igniter and burner- it should be 3/16″ and centered above the burner.
A comparison of the “bad flame” versus the “good flame” shows the difference- on the left is the “lazy” bad burning flame, on the right is the “hard blue” flame- and with the small amount of LP that is used in a Gas Electric refrigerator, a small problem with the flame can mean a huge difference in cooling power.
Now simply replace the sheet metal, and you are good for another year.
This job is not at all hard, though it does involve working with the LP system- if you have any doubts- have a qualified service center do the job, but if you are handy and a “DIY” kind of person- I hope this gives enough information to help you get the job done.
Questions, comments? See this thread on the RV.Net forums.