Norcold - Automatic Electric/Propane Issues

Harvester · 06-14-2021, 10:39 AM

I have a 2020 Minnie Winnie 22R with a Norcold Polar series refrigerator. Not sure of the exact model (N7 or N8), but it uses electric and propane - and has an automatic mode.

First thing to mention, is that the refrigerator does have the ability to get cold. In fact, under certain conditions will start freezing things if we leave it on the 5-star setting. The issue I'm having is when the refrigerator switches from electric to propane, and then back. When we do longer distance road trips, we're usually staying at a place for one or maybe two nights, then move on. Were also stopping at rest stops along the way and turning on the generator. Generally, before we take one of these trips, we'll turn on the fridge using electric for 2-3 days before going. By the time we're loading things up, the Norcold seems to be doing exactly what it's supposed to do.

We've had the RV for just over a year, and I've periodically noticed that sometimes the temperatures would seem barely cold at all during the course of a journey. Then after a day or so, it would get much colder. So I bought a temperature/humidity sensor (SensorPush), which by the way works very good, to start collecting data on the cooling. It creates graphs on your mobile device to show what's happening over time down to one minute granularity.

From these observations, I noticed extreme variations when going from electric to propane. This could be exacerbated by outside warmer outside temps, but not always. So as an example, the fridge temperature at our departure would be right at 39 degrees. Then we arrive at our first campsite, it's showing 50 degrees. Then plug-in, and overnight drops back to 38-39. The most telling example was at Big Bend National Park with no hookups. It was 5400 feet elevation at the campsite, and we turned on the generator for about one hour. The fridge then spent the next 12 hours going all the way up to 61 degrees on propane, and then in the middle of the night drops all the way back down to 37 degrees. I thought at first I was brushing up against the elevation limits of the fridge (5500 feet), but similar things happen at lower elevations. It then occurred to me, to avoid using the auto switchover, and force it to use propane only. It seems to behave a bit better by doing that. At least when we pull over to a rest stop and turn on the generator, it doesn't mess with fridge's cooling operation.

My question to the community, is whether this is normal behavior for the Norcold. I called Winnebago support, and they seem to think this is not normal, and needs to be looked at. That said, the support person appeared to be rushed, and not sure he was thinking everything through. So before I head to an RV shop, I wanted to see if anyone else has had similar experiences.

Thanks.

**creativepart** · 06-14-2021, 10:54 AM

What happens when you turn it off of Auto and just manually select LP when you're traveling or don't have shore power and then select AC when you have shore power?

Does it run correctly if you do this?

Morich · 06-14-2021, 11:13 AM

This sounds like a time when we might be easily confusing things due to timing and what we see may not always be spot on.
So I would want to do some testing on the controls. One that is semi-easy to test is the thermistor that acts as the thermostat for the frig.
A search for "Norcold thermistor testing" will likely get lots of info on exactly how to do it.
Just step one of several things that might be going wrong like the board or loose wiring but this is one where we can get actual numbers to guide us. And it is true that a goofy thermistor WILL make the temperature swing way off.

Harvester · 06-14-2021, 11:21 AM

I haven't done extensive testing of leaving it on LP, but my initial results would seem to indicate to just leaving it in that mode may be preferred. So in my case, I would plug into electric (in the storage facility) about 2-3 days before a trip as usual. Then for the remainder of the trip just use LP.

From my way of thinking, this is not optimal as you're always using LP. It would be better to use the automatic switchover to conserve propane. If this is a problem and there is a fix, I would want to explore that.

Morich · 06-14-2021, 01:24 PM

As a thing that seems to come up often, maybe a look at the back side of the frig to see if there is anything like wasp/mud dauber nests in any spot that might tend to make airflow not reliable, may help???

These frigs work by heat flowing up and around the liquid used and if it get blocked it might tend to be borderline on operation?
It doesn't really sound like it is working nearly as well as I would expect, though. We go with just running it on AC a day before we load and go and it gets plenty cold in that amount of time, so if you are needing several days, that is an indication things are not right!
The flakey, come and go aspect makes things hard to sort, for sure!

Harvester · 06-14-2021, 01:49 PM

Quote:

Originally Posted by Morich

As a thing that seems to come up often, maybe a look at the back side of the frig to see if there is anything like wasp/mud dauber nests in any spot that might tend to make airflow not reliable, may help???

These frigs work by heat flowing up and around the liquid used and if it get blocked it might tend to be borderline on operation?
It doesn't really sound like it is working nearly as well as I would expect, though. We go with just running it on AC a day before we load and go and it gets plenty cold in that amount of time, so if you are needing several days, that is an indication things are not right!
The flakey, come and go aspect makes things hard to sort, for sure!

Yes, I actually make regular inspections on that outside access behind the fridge. The RV storage facility does have wasps flying around from time-to-time, so I keep an eye on that.

I did watch some videos on the thermistor test, and that is a possibility. However, the specific behavior I'm seeing isn't quite like what these people are experiencing.

Morich · 06-14-2021, 04:28 PM

Quote:

Originally Posted by Harvester

Yes, I actually make regular inspections on that outside access behind the fridge. The RV storage facility does have wasps flying around from time-to-time, so I keep an eye on that.

I did watch some videos on the thermistor test, and that is a possibility. However, the specific behavior I'm seeing isn't quite like what these people are experiencing.

YUP! Seems like something else but thought to try an easy way out.
Can you spot any easy way to add course scree over any vents. I found I couldn't work fast enough to keep them cleaned out and went for screen on furnace, water heater, and frig.

Harvester · 06-14-2021, 04:45 PM

Quote:

Originally Posted by Morich

YUP! Seems like something else but thought to try an easy way out.
Can you spot any easy way to add course scree over any vents. I found I couldn't work fast enough to keep them cleaned out and went for screen on furnace, water heater, and frig.

I've got those screens (from Bouge RV) on my heater and hot water vents - which are very nice. I also got the screens for the fridge vents, but had to modify them with small metal shears to fit my particular vent opening. The screens from Amazon were a bit too large, and needed rounded corners. However, I ended up removing the fridge vent screens, as I was concerned about airflow and heat build-up. I've had these fridge issues for some time now, and wanted to eliminate that possibility. Once I get this figured out, I'm ready to tie-wrap them back on.

KGs2108DS · 06-27-2021, 04:27 PM

Our Dometic 3 way fridge works GREAT on LP - freezing unit 6-10 degrees F and fridg 38ish! You should not have to turn the generator on periodically during travel, and the on-board 12VDC battery is continually kept charged while driving, so not sure why you’re using the generator. It astonishes me how little battery juice and LP for that matter the fridge uses! Also, we’ve used it way above the altitude you refer to, up to 10600” with no problem whatsoever. I start it 48 hr prior to departure and pack it 16hr prior to departure, and it dose the rest. Last summer 10 days all over Colorado and apple pie with ice cream every evening - what great times! When boondocking we use honda 3300i for about an hour in the pm to recharge on-board 12VDC, and again about an hour in the AM. HOWEVER, i recently ran the fridge ONLY on LP for 48+ hours, and still maintained temp and batt only about 1/2 depleted.

Harvester · 06-27-2021, 04:59 PM

Quote:

Originally Posted by KGs2108DS

You should not have to turn the generator on periodically during travel, and the on-board 12VDC battery is continually kept charged while driving, so not sure why you’re using the generator.

We turn the generator on typically when we stop for lunch. That way we can use the microwave and run the air conditioner. The issue is not about the electrical supply, but about the actual switching between propane and electric when the Norcold fridge is in automatic "A" mode. When we leave a campsite and are driving, it switches to propane. When we start the generator up, it switches back to electric. When we turn the generator off, it switches back to propane, and so on. However, nice to know that you had good refrigeration at that high of an altitude. I'm also planning to visit Colorado, and was actually concerned about that.

A little bit of an update here:

I finally took the RV to a local repair shop. In short order, they witnessed this problem of switching from propane and electric. After a couple days over there, they reported to me that the Norcold is simply not turning on after the switchover. It sounds like it is trying, and sometimes after about 2-6 hours it finally kicks in. They see a lot of these refrigerators, and it's a first for them. One possibility may be the control board, and the other is something else which they haven't mentioned yet. The two technicians are debating the best course of action, as one of these possible solutions will require pulling the fridge out and end up costing 3 hours of labor (i.e. it will be sort of pricey).

Harvester · 06-27-2021, 05:15 PM

Quote:

Originally Posted by creativepart

What happens when you turn it off of Auto and just manually select LP when you're traveling or don't have shore power and then select AC when you have shore power?

Does it run correctly if you do this?

If I manually select LP and leave it in that mode, the fridge seems to work fine. However, it appears that it takes time (sometimes hours) for it to start working. If I leave it in that mode, it'll just keep running. Same story when I go to electric. As noted in my recent post, a couple of RV technicians are working on this now, and seeing the problem first hand. Once the solution is found, I'll be sure to post it here.

Harvester · 07-01-2021, 11:37 AM

After several days at an RV tech/repair shop, they identified the problem. It turned out to be a power supply control board. They mentioned that these were symptoms that they'd not seen before, but verified that when switching from propane to electric, there was no current going to the heating element. After some time, maybe 2-12 hours it would just randomly start working.

At one point they thought it might be a malfunctioning thyristor. This would have required full removal of the refrigerator to replace that component. In any case, it turned out to be the control board - and much less expensive.