Norcold N811 Problem

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rjay

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May 7, 2024
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Arkansas
I have an older fifth wheel with a Norcold N811 which has always worked well. It works fine on AC power. Couple of weeks ago I was primitive camping and running on propane. The burner came on normally and got the refrigerator cold but would only run a few hours and start flashing the gas check light. I made it through the week but when got home started trying to figure it out. I removed the burner which looked fine but still cleaned it thoroughly , the flame is very good and the igniter tip is cherry red. I replaced the igniter even though probably nothing wrong with the original one.

The problem it has now is running on gas the burner comes on fine and will run for hours and it will get cold but then sometime overnight something fails. The next day the burner will not be on, the auto light flashing 5 times but the gas check light is on solid and not flashing. I have reset the control board by shorting pin 15 to ground and taken all the gas lines and valve off and checked for obstructions and cleaned and switched to the other tank.

Any one seen this before or have any ideas? Thanks
 
Get a manometer and check your gas pressure, preferably at the test port on the solenoid valve of the fridge. If not there, then at least at an outside BBQ grill connection or water heater test port.

Charles
 
The gas check light simply means the burner failed to re-ignite at some point. Since it is intermittent, troubleshooting the "why?" is going to be challenging. Slightly low gas pressure is a possibility, but so is a circuit board ignition glitch (the board sorts internally as a result of heat expansion/contraction) or a poor quality connection where the igniter wire meets the board.
 
What puzzles me is the fact that when I check it the next day, the gas check light is ON and not flashing but the burner is off and the green light is doing the 5 blinks.

The gas check light will blink if I turn the propane off and it fails to re-ignite so I know that part of the control board works. I am leaning towards a control board problem but just trying to eliminate any other cause.
 
Yes, I looked at that manual. Nowhere in there can I find a reason for the gas check light to be on solid when the burner is not on.
 
Have you done as suggested in reply #2 and had the propane pressure checked? There must be some reason for the failure to ignite the propane. Am I understanding correctly that the failure only happens at night? If you correct it in the morning it then works until night?

Low voltage can cause some strange issues as well and failure to light is one of the more common ones so check that as well.
 
Not necessarily at night but it will stay on hours and appear to be working but when I check it the next day it is in this state. No one seems to have an answer why the gas check light is not blinking when the burner is not on.
 
I don't have a manometer to check pressure so I have connected a stand alone bottle through a different regulator directly to the gas valve. I see no difference in the burner flame but when I get a day off I'll let it run all day to test.
 
Not sure about the pressure but I plan to test it with a stand alone bottle and regulator which should eliminate any problem with the RV supply. After talking to dinosaur electronics guy he thinks it is just not getting cold enough in the allotted time so the frig is faulting out and doesn't try to re-ignite so the gas check light is not blinking. He suggested making sure the flue is not obstructed which I had not thought of but will check it.
 
While checking the flue is a good idea, I don't buy that it is getting an error from too slow cooling as no such error exists in any of the refrigerator control circuit boards that I have seen either OEM or from Dinosaur. Have you tried the internal diagnostics on service manual pages 63 & 64? You could read the temperature seen by the thermistor.

Something that you might do is to lift the 2 pin connector for the thermistor from the control circuit board which will then cause it to go into continuous cool mode, which is a feature of both OEM and Dinosaur control circuits for the N811.
 
Last edited:
Did you clean the jet/orafice?

Is there debris on the burner?

Either of those can cause intermittent ignition issues.
 
This is the message I received from the Dinosaur tech:

The light your seeing is a no cooling light saying the cooling unit took too long to hit temp and something is going on because the board saw power to the AC heater, or a flame present for a full four hours and it didn't cool in the last hour. Try cleaning your flue tube.
 
"No cooling" is more likely a sign of a cooling unit deteriorating toward total failure. A pinhole leak or tiny crack will let the hydrogen gas in the coolant leak out first and cooling deteriorates. Then the ammonia itself slowly leaks away.

However, it's possible the gas heater flame isn't fully transferring its heat to the boiler and that would have similar results. Typically the burner chamber has a plate above the flame whose job is to capture the flame btus and heat the boiler. Rust flakes, dirt or insect nests can interfere.
 
I don't think that any of us realized that it is working properly when on 120V power. In that case, I would agree that cleaning the flue and related parts is the next thing to do.
 
it actually cools on propane but at some point the burner goes off and Gets the 5 blink fault. So I'm trying to cover everything involving the gas side
 
I looked at the flue using a mirror Not sure how to go about cleaning that thing I guess have to remove the baffle from the top somehow Mine has the roof vent
 
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