Adjusting thermistor on an Norcold N3150

You are correct there about them being more problematic today than in the past.

If I have problems with this it well be history in my MH. I'll be pulling it out and putting in a Nova Kool with a couple of more batteries and some solar. I have a couple of portable Dometic cooler/freezers with the Danfoss compressor and they work like a champ. In the same space that the Norold takes up I can put in a Nova Kool that is 1.5 cu ft bigger. In fact it takes up a little less space. Than I can also close off the outside vents which helps with the mud dabbers making nests in my fridge compartment.

But that is for another thread.

Control parameters for thermostat are based on specific fin ...... moving thermistor on an adjustable temp control will not affect thermostats parameters.


RV fridges are more problem today then years ago.
More bells/whistles. More expectations to be like a compressor fridge, thinner tubing due to costs, lack of RV Mfg. following fridge mfg. installation requirements, installations in slideouts, installations angled, baffles/no baffles, fans/no fans etc. etc.

Absorption fridges CAN freeze & maintain food just like a compressor fridge WHEN properly installed.

Old-Biscuit,

Thanks for all your help.

I still do have a question for you.

If the thermistor tells the controller to be 10* above the temperature of the fin it seems to me that moving the thermistor to a fin that does not have any frost forming on it would cause the fridge to run lower. A fin with no frost is going to be warmer than one with frost on it. Or am I just off the mark here.

I have RVing for over 40 years but this is the first time I've had every had any problems with a fridge.

Auto defrost mode.........that will cause temp fluctuations on food compartment

Opening/closing door a lot doesn't help..........all the cold air gets pulled out when you open and a whole bunch of warm (moist) air gets induced when you close door and UNLIKE compressor fridges that's a lot of EXTRA cooling demand on absorption fridges....they just can't remove that extra warmed as quickly so that will also cause temp fluctuations.


Having to use highest temp setting in a hot/humid area is not unusual either.

Think you have 'jumped the shark' :B

Old-Biscuit wrote:
IIRC the thermistor should be on 10th fin from right

That moving of thermistor on Dometics is for those models that have a factory pre-set thermostat ......non-adjustable.

With adjustable temp controls thermistor are 'fixed' position on specific fin to give feed back on fin temp (fin temp 10*f lower than compartment temp)4


What fin is your thermistor on?

It is on fin 11 from right.

Fans running in outside compartment?

Yes, the fan cycles off and on.

Freezer temp is a bit high (5* to 8* ------ S/B 0* to 5*) That shows cooling unit is NOT performing as well as it should.

I was just out checking the temps and the freezer is running 2* and fridge is 35*. This is with the controller turned up to the max setting of 5

Food section fins frosting up.........door seals or warm air coming back up drain hose.
Maybe install a circulating fan in food compartment.

I just bought a fan and it is running in the fridge at this time.

Check for any obstructions that would disrupt draft.
And if Winnebago didn't follow Norcold's installation CLEARANCES & use of baffles then air flow across back is not correct.

It is a side vent unit so pretty hard to see if any thing is blocked but I do feel heat at the top vent and it blows pretty strong when the fan is on.

RV IS Level...correct?

Yes, I'm a stickler on having the RV level. I use a round bubble level and I have a spot in the RV that is level but I always check it in the bottom of the freezer box also.


Installation Manual

I have already downloaded the manuals for it

The frost is because I have been opening it and closing it a lot messing with it right now. This morning the unit went into its cycle and the frost is gone now. The unit has a set up that the temperature control automatically melts the frost on the fins. This is per the manual.

We were also in Memphis when this happened which was very warm and humid. Also as we were driving down there it was about 98 to 99* out and heading east put the side of the coach with the fridge in the direct sun, then the campground sites were situated so the same side was right in the direct sun.

We are heading for the PNW in a couple of weeks so I'll see how it operates then. It should be cooler then also and the fried will be on the north side of the coach most of the way and out of the sun. We well be gone for about a month so I should have a good indication how it operates over a long period of time. When it is sitting in my parking space at home (where we are hot and humid also) it seems to run just great and usually about 3 to 4* in the freezer and 36 in the fridge on setting 3 on the control panel.


I think maybe I'm over reacting. I have a portable Dometic cooler/freezer that we are taking with us and it well be operating in freezer mode so I'm going to take some blue ice packs and freeze them in it over night and if needed I can use them in the fridge. The Dometic has the Danfoss 12VDC compressor in it and boy does that thing work great.

Thanks so much for your help.

Ford's Rv, Benton, Ky... fixed our fridge troubles... GREAT peoples...

try this just for fun,, put a bungee cord across the door just a little tension, let sit 5 hours bet the temp drops.

IIRC the thermistor should be on 10th fin from right

That moving of thermistor on Dometics is for those models that have a factory pre-set thermostat ......non-adjustable.

With adjustable temp controls thermistor are 'fixed' position on specific fin to give feed back on fin temp (fin temp 10*f lower than compartment temp)4


What fin is your thermistor on?

Fans running in outside compartment?

Freezer temp is a bit high (5* to 8* ------ S/B 0* to 5*) That shows cooling unit is NOT performing as well as it should.

Food section fins frosting up.........door seals or warm air coming back up drain hose.
Maybe install a circulating fan in food compartment.

Check for any obstructions that would disrupt draft.
And if Winnebago didn't follow Norcold's installation CLEARANCES & use of baffles then air flow across back is not correct.

RV IS Level...correct?


Installation Manual