Norcold fridge problem

Discussion in 'RV Tips & Tricks' started by Gil, Jun 28, 2015.

  1. Gil

    Gil Junior Member

    I have a 2006 Norcold 821LT 2-way RV fridge. The fridge is like new, not used all that much, there’s no signs of leakage on the coils, there’s no smell of ammonia and there’s no signs of overheating inside the fridge or freezer. It works perfectly in AC mode. When I switch to propane, the burner fires properly and instantly, (nice blue flame right in the middle of the burner chimney) and burns for at least a couple hours. If I try and blow out the flame, it instantly re-ignites. There’s no rust on the orifice etc. However, in propane mode with the flame burning, the cooling unit quits heating up (even after it was already warm and flowing in AC mode) and eventually the fridge quits and gives me an "n" error code. (The manual says the “n” code means cooling unit has stopped working; not serviceable; see your RV dealer). I clear the code, fire it up in propane mode and same thing happens again. (i.e. the burner fires up for an hour or 2 but the coils stay cool and the fridge shuts down with the “n” code displayed again). This happens regardless of whether I'm operating on 12 volt DC, or if I'm plugged into 110V. I just put in a new dinosaur circuit box and my thermistor appears to be ok. All my fuses are good and breakers have been tripped. I usually have the fridge temp set to 5, 6 or 7 out of 9, when all of the above is happening. Any idea what I should check next? Could it be a faulty propane valve solenoid with these symptoms? I appreciate any and all advice. Thanks for your help! Gil
     
  2. C Nash

    C Nash Senior Member

    Welcome to the forum Gil. Have you checked the flue for obstruction?
     
  3. Gil

    Gil Junior Member

    Hi Mr. Nash, thanks for the advice! I haven't checked the flue for obstruction, but that was my next play. Do I check the flue by removing the roof exhaust cover and look down into the flue or from the burner chimney looking up with a mirror?? How do you suggest I check the flue for obstruction, and if there is, how do I clear the blockage? Gil
     
  4. C Nash

    C Nash Senior Member

  5. C Nash

    C Nash Senior Member

  6. Gil

    Gil Junior Member

    Thanks for these links Mr. Nash. I read them and continue to learn more about my fridge. Last night I took apart the burner assembly and inspected it. It looked clean and perfect. I blew it out with compressed air just to be sure. The orifice was good, no plugging at all, no rust. I used a small LED light and mirror to inspect the inlet of the chimney [FONT=&quot]flue where the burner flame is drawn. The flue and baffle looked clean and unobstructed. I could move the spiral flue baffle up and down about a 1/4 to 1/2 inch to confirm that it was not lodged/plugged. I directed compressed air into the flue as best as possible to blow any debris out if there was some. There didn't seem to be any problems. I didn't remove the flue baffle through the top of the flue chimney as that would require that I take the fridge out of the camper. (I don't think I can [/FONT]remove the flue baffle from the top of the chimney flue though the roof vent as it appears to be congested coming at it that way).
    [FONT=&quot]
    I put everything back together and (in propane mode), confirmed that I still have a nice blue flame being drawn right in the middle of the flue pipe. There doesn't appear to be any issues with the flame. The flame was being properly drawn with a slight draft into the chimney flue and burned for at least an hour and a half (as I went to bed and did not confirm when it actually went out); After burning for at least an hour and a half, the heat shield area around the flue inlet was fairly hot; however, none of the cooling unit coils were warm and of course the fridge was not cooling. When I checked it this morning, I had the usual "n" code display on the fridge and the burner flame had quit. The fridge was not cool and the cooling unit coils were not warm. I cleared the error code, and started the fridge again in propane mode. It started instantly and stayed on. The flame was perfect as usual.

    This is a repeat of what happens every time. In propane mode, the flame burns properly for at least a couple hours but the cooling unit coils don't get warm and of course I get no cooling in the fridge or freezer. The burner eventually shuts down and I get the "n" error code. When I clear the code and start the fridge up in propane mode, the flame lights right up and stays lit but I get no cooling going on. When I change to 120 AC mode, the [/FONT]
    cooling unit coils get warm quite quickly, the freezer starts freezing within about an hour and the fridge gets cool as it should indicating that the cooling unit is working properly, so I assume the thermistor is working properly as well. I'm baffled by this problem. My 12 volt batteries are not the issue as they are new and I have 12.5 volts DC coming into the circuit box. As I mentioned before, the flame will burn for at least a couple hours before shutting down, but even after a couple hours of burning, the cooing coils are not hot (except for about 6 inches of HORIZONTAL tubing just below the burner...the section of tubing that returns fluid to the bottom of the chimney flue to be reheated again). All indications seem to point to a plugged chimney flue, yet I see no signs of plugging, the burner flame is strong, burning properly and being drawn with a proper draft into the center of the chimney flue. Is there some kind of electronics that control the action of the spiral flue baffle? Is it possible that the flue baffle could be stuck in a "closed" mode and therefore not allowing burner heat to properly flow up the chimney flue to heat the boiler unit portion of the cooling unit?? Thanks for your on-going advice. I really appreciate your help! Gil
     
  7. C Nash

    C Nash Senior Member

  8. Gil

    Gil Junior Member

    [FONT=&quot]Hello fellow RVers![/FONT]
    [FONT=&quot] [/FONT]
    [FONT=&quot]Special thanks to Mr. Nash for your advice. I finally got to the bottom of my issue. It turns out that there was light oil in my propane lines that was causing enough blockage that propane pressure was enough to fire a light flame in the burner but insufficient enough to properly heat the boiler unit. I blew out the oil from the main metal propane line under the RV with an air compressor. I also disconnected the propane supply line to the fridge as well as where that line connects to main metal propane line under the RV and back-blew air pressure down to clear more oil from the line, since there was a low point loop in the copper line where oil was collecting. I reconnected everything, check for leaks and fired up the fridge. I had a reading of 8.5 “inches of water” on my pressure gauge and a nice hot flame from the burner. My fridge immediately started to cool in propane mode. Problem solved! [/FONT]
     
  9. C Nash

    C Nash Senior Member

    This for the follow up Gil. This will help others
     

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