refrigerator "pop pop pop"

[siguccs]

I recently purchased a used motorhome with a Norcold refrigerator model 1201LRIM. It has been modified under the recall, and does keep things cold.

Inside the coach, however, you can periodically hear "pop" or a series of several pops, like little backfires from the refrigerator when it's running on propane. It doesn't seem to be associated with startup or anything else. It's just random and can stop completely for hours at a time. One thing I do know is that it isn't the spark ignitor - which admittedly can sound about the same. The previous owner says this has been happening for a long time.

If you look at the burner from the outside, the "pops" are associated with a small and fleeting blue flame coming out the mixture holes. I took out the burner assembly and cleaned out the rust with compressed air, being super careful to not touch the orifice. I tried reducing the air intake by slightly covering some of the holes. I also tried reducing the propane flow with the manual cut-off valve next to the 12V solenoid. None of this had noticeable effect on the random backfires.

Anybody have any suggestions as to how to repair this? btw, Norcold says this is "not normal", but maybe that's the safe answer they give everyone!

[jwmII]

Remove the tin shield around the flame. Be sure the fridge is off and the burner has cooled. Cover the burner so particles , dirt, rust, etc, cannot enter the slots on the burner cover. Get on the roof and remove the fridge vent cover. It will be necessary for you to remove the baffle in the boiler tube. It is on a wire anchored at the top of the boiler tube. Unhook it and just pull it out. Don't forget to put it back when cleaning is done.. Ideally a 10 gage shot gun cleaning brush just fits the boiler tube. A 12 gage will do. run the brush down in the boiler tube and clean the rust flakes out of the boiler tube. The cover below hopefully keeping any junk from entering the burner. Once done with this go back and go back over all the stuff you cleaned previously. DONOT put anything thru the gas orifice to clean it up. Instead soak in denatured alcohol then blow everything clean and dry with compressed air. If you do not have access to compressed air go to an electronics or computer store (RADIO SHACK) and get a can of clean instrument air. Since you are the second owner and the first owner had the problem chances are good that this has been building up to the present problem and this will hopefully clear it up.

[mchero]

Good Job! Congrats.
We aquired our new to us rig last spring. It had a Norvold 4 door that was gassed out! I installed new Amish unit & it's back to 100%. Icemaker went this spring. Found exact replacement at Lowes for $99

[siguccs]

follow up:

I replaced the burner with a new-style orifice and burner with 7 slots instead of 8. The popping is gone, and I believe the 7 slots mean it will run cooler.

Thanks for your help.

[ejmorgan]

My 10 year old Norcold N621L was making an intermittent bumping or burping noise while running on propane. I observed the "blue burner flame" flicker whenever the noise was heard. Cleaning the burner orifice did NOT help. Replacing the burner orifice assembly with a NEW one solved the problem.

Ed

[Rvpapa]

Pretty good chance the chimney tube needs cleaning.
Art.

[MitchF150]

Mine does something similar when it's cold outside and the fridge cycles off/on while on propane.

I think it's the metal flue/tubes expanding after the burner turns on after it's been off for a little while.

My fridge will maintain a set temp by cycling the flame off/on. This is really only noticeable in the middle of the night when there are no other sounds. I can even hear the igniter turn on and about 10 seconds later, the little popping sounds for about a minute or so.

Good luck!

Mitch

[downtheroad]

"I tried reducing the air intake by slightly covering some of the holes. I also tried reducing the propane flow with the manual cut-off valve next to the 12V solenoid."

I wouldn't be doing any of this...put it back to normal and clean out the burner tube..Probably some debris in there...like a wasp nest or more likely a spider web.