Norcold 811FRT fridge intermittently works

RI

Rikopus

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Joined
Feb 16, 2016
Posts
10
Hello
Norcold 811xxx (on a 2016 5th wheel) fridge works occasionally on 110 and/or propane! Replaced thermistor and power board. Cooling fan working. Fridge worked great from 2016 - 2023. Started acting up late last year. Changed out the power board on July 8. Fridge worked fine for 8 days -7 in freezer, 35 in fridge, then temps started to go up, up, up.

July 20, 2024 it started working again after I unplugged it, waited 30 seconds and plugged it back in, plus moved the temp setting on the fridge door back and forth. (I'm trying anything now). Temps dropped down in freezer from 44 to 17 and fridge from 60 to 48. We had to leave, so I don't know if it still works or not. But, this is my typical "go to" work around when it stops cooling.

I'm stumped.
 
First of all, you can download a copy of the Norcold 811 Service Manual to use in your troubleshooting. While seven years of operation is a bit short, it sounds to me as though you may have a partial blockage of the refrigerant path in the cooling unit that accounts for the intermittent failures. The -7 in freezer, 35 in fridge are pretty normal temperatures if it is set toward the maximum cooling side. As a test you could disconnect the thermistor from the main circuit board which will trigger a continuous cool mode and monitor the temperature in the chill box area as that is where the temperature control is sensed. Also, examine the rear of the refrigerator for any yellow material or ammonia odor as those are indications of a refrigerant leak.
 
Thank you, Kirk

I checked for ammonia odor/yellow material and there is none.

I will try out your suggestion regarding the thermistor.

I really appreciate your feedback.

R
 
The yellow and the ammonia smell as indications of leakage but the blockage would not show outside the piping. The most common cause of a blockage would be crystallization of the chemicals in the refrigerant. That is usually caused by operating the refrigerator too far off level. It should be within 3° side to side and 6° front to back of the refrigerator.
 
Thanks again, Kirk
As far as I know, my 5er has always been level. However, I certainly could be wrong in that I put my trust in the Lippert auto leveling system and don't verify "levelness" every time I set-up. I will certainly double check for level the next time I'm at our seasonal campsite.

R
 
When your RV is level enough that you don't notice the difference it is most likely within the limits of the refrigerator requirements. While 7 years is a bit early to have a cooling unit failure, it has been known to happen. Good luck!
 
Thanks for the Good Luck wishes, Kirk. Not fun, but certainly not the end of the world.

Take care!
 
Kirk said:
The yellow and the ammonia smell as indications of leakage but the blockage would not show outside the piping. The most common cause of a blockage would be crystallization of the chemicals in the refrigerant. That is usually caused by operating the refrigerator too far off level. It should be within 3° side to side and 6° front to back of the refrigerator.
Click to expand...
We are having similar issues to those of the OP with our Norcold N10LX. Both on propane and AC, temperature of the frig has varied rather widely. On our first day out, the frig cooled to 44F, then rose to 52. I can't remember all the fluctuations, but it hasn't been stable. An RV repairman looked at it and couldn't find problems other than a thermistor that wasn't turning on the fan which exhausts heat from the propane flame. He bypassed that, so the fan runs full time, but I don't think that fixes the main problem. He thought that if it keeps acting up, it likely shows blockage as you described. It has been doing better, but the temp doesn't seem completely stable. It has been varying between about 38 and 42 for two days--then it went to 48--and back down to 39!

Questions: Does blockage as you described ever cure itself? It seems like crystals could be redissolved in a sealed system, but then I'm not sure how crystallization occurs in the system. As far as the angles, 6 degrees is a 10% grade and we've travelled on hills that steep--up to 17% on the Gaspe Peninsula. In fact, there is a very short grade of about 20% or more getting into our storage unit. I wonder if acceleration and deceleration during driving wouldn't have the same effect as tilting on the frig?

I have seen someone claim that the propane should be off while on the road, i.e. frig would be off on travel days! I believe most RVers have their frigs running on propane while travelling.
 
Last edited:
Traveling on grades isn't an issue for the fridge - you have to be stopped for hours at the off-angle to have a noticeable negative effect.

The thermister (which is inside the fridge) doesn't turn anything on or off - it just signals the interior temperature to the control circuit board. It has nothing to do with fans. The vent fan has it own thermostat which directly reacts to exterior temperature and activate the fan, typically at about 130 F.

There are a couple kinds of "blockage" that affect cooling. Kirk was referring to a chemical blockage inside the cooling unit. It won't ever dissolve on its own, but sometimes it can be dislodged and move to a different point in the unit. Maybe a less harmful spot, or maybe worse. The other type of blockage inhibits air flow around the cooling unit. It's not just the propane heat that has to be removed - the cooling unit condensor has to shed heat as part of the cooling process. The area behind the fridge acts as a chimney to do this and is assisted by a fan if temps are extreme. If air cannot steadily flow from bottom to top and out the upper vent, cooling can be erratic or non-existent. Sometimes the factory installation is faulty and that "chimney" is blocked by wiring or the spaces at the side & top of the fridge are not sealed off. Another possibility is a bird or animal nest got built in there.

Is the fridge in a slideout by any chance? If so, the upper vent is on the sidewall rather than the roof and venting is less effective than via the roof. Problems such as you describe are more common.
 
Gary RV_Wizard said:
Traveling on grades isn't an issue for the fridge - you have to be stopped for hours at the off-angle to have a noticeable negative effect.

The thermister (which is inside the fridge) doesn't turn anything on or off - it just signals the interior temperature to the control circuit board. It has nothing to do with fans. The vent fan has it own thermostat which directly reacts to exterior temperature and activate the fan, typically at about 130 F.

There are a couple kinds of "blockage" that affect cooling. Kirk was referring to a chemical blockage inside the cooling unit. It won't ever dissolve on its own, but sometimes it can be dislodged and move to a different point in the unit. Maybe a less harmful spot, or maybe worse. The other type of blockage inhibits air flow around the cooling unit. It's not just the propane heat that has to be removed - the cooling unit condensor has to shed heat as part of the cooling process. The area behind the fridge acts as a chimney to do this and is assisted by a fan if temps are extreme. If air cannot steadily flow from bottom to top and out the upper vent, cooling can be erratic or non-existent. Sometimes the factory installation is faulty and that "chimney" is blocked by wiring or the spaces at the side & top of the fridge are not sealed off. Another possibility is a bird or animal nest got built in there.

Is the fridge in a slideout by any chance? If so, the upper vent is on the sidewall rather than the roof and venting is less effective than via the roof. Problems such as you describe are more common.
Click to expand...
Thanks for the help. Perhaps it was a thermostat rather than a thermistor bypassed; it was external, accessed through a cover on the roof where the frig heat vents. He measured 300 F on the "chimney" for the gas flame and the fan was not turning. He also inspected for foreign materials and such.

He moved the thermistor inside the frig higher on the vanes, which I believe is supposed to do the same as lowering the thermostat setting. At some point, the frig was approaching freezing, so I set the frig to a lower number and I'm still trying to fine tune it. It seems to hold in a 3-4 degree range, then vary upwards by 6 or so degrees briefly. Blue ice containers in the freezer are measuring 0 degrees.

My current thinking is that the blockage got a little better. You didn't mean that there is any way to help it, right? Although it worries us, it is keeping food in a safe range. Some milk and broccoli went bad from the earlier excursions over 50. If it gets that bad again, we'll buy ice--or even make it. We're in Utah and headed for Colorado, then the northern Rockies. I think it would be difficult to find a frig in stock and have it installed while we're on our trip

We don't have slideouts, thankfully. I just saw a photo of someone on a freeway with theirs slid out!!!
 
Hello. OP here. I wish there was something extraordinary and uplifting I could add to this thread. But nothing has changed. Fridge is still working whenever it feels like it. I have a Webcam that I use remotely to check the freezer and fridge temps via a digital thermometer. When we are not at our seasonal site, I watch the temps rise and drop over the days we are away from the camper. But! so far, when we arrive at our site, I unplug the fridge, wait a bit, plug it back in and so far, the temps drop and the fridge and freezer works fine for 3 or 4 days. If I notice the temps rising (freezer above 0 or fridge above 40) I unplug and replug and I'm back in business.

R
 
I think you are seeing the defrost cycles. The fridge controller will periodically let the temperatures rise several degrees. Unplugging resets the defrost interval timer, so you get another 24 hours or so of uninterrupted cooling. Quite a few owners complain that the defrost cycle gets warm enough to put food at risk. Nor is it clear what the "defrost" achieves, since these absorption fridges aren't actually self-defrosting like a residential type fridge.
 
I probably didn't word this correctly. We've been home (away from our camper) for 5 days now. We leave the refrigerator plugged in. As of today, I'm seeing freezer temps of 22 degrees and the fridge at 48.
 
Higher or lower on the vanes is a common misconception. The exact center of the vane is the coldest part. Putting the thermistor exactly in the middle will result in a higher refrigerator temp.

If you want colder refrigerator temps move the thermistor further from the center. Up or down, it doesn't matter. I use down just to be consistent.

The same it true, to a limited extent, regarding the vane the thermistor is attached to. Moving it further away (right or left) from the center will lower the refrigerator temp.

Maybe an adjustable thermistor makes more sense? They're usually not on the vanes.
 
Kirk said:
How long do those temperature increases last? Do temperatures return to what they should be in time if left alone?
Click to expand...
Hello Kirk
2ND question first: Temperatures rarely (maybe once) do not return to what they should be if left alone. Right now, 8:00am the temps read freezer 17 fridge 46. We've been away from the trailer for 6 days now. 1st question: Temp increases last the whole time we are away. Temps will fluctuate up and down, but )except for one instance), never settle down to the point where we can show up and transfer cold food from our cooler into the fridge. I go through the unplug, wait, replug, and wait about 8 hours, watching the temps drop to operating levels.
 
Sorry to be slow in responding, but I have been under the weather. The way that an RV refrigerator works is that the refrigerant passes through the freezer first and then whatever cooling capacity is left is used as it enter the chill box area. I still believe that you have a failing cooling unit.
 
Hope you are feeling better, Kirk. I agree with you. A failing cooling unit is the culprit.

Thanks for your input and also thanks to everyone else who responded.

Much obliged!
 
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