Refrigerator is freezing our food

Old-Biscuit wrote:
Thermostats on fridges with adjustable temp settings are pre-set at factory for specific temp range and calibrated for those temps based on OEM position of thermistor on fin.
Thermistor just senses the fin temp so when the pre-set temp is reach the thermostat shuts off 'heating'

Auto Temp Control uses the thermistor as the setting for temps.
Moving thermistor UP/Colder (warmer fin) thermostat continues 'heating cycle' until temp is reached .....longer heating cycles
Moving thermistor DOWN/WARMER (colder fin) thermostat continues 'heating cycle' until temp is reached.....shorter heating cycles
Overall affect is 6*F-8*F

It looks like my understanding is sound, The only difference between the fridge types then is that an adjustable fridge has multiple “expected” temperature choices versus the other that has just one. Both can be “adjusted” by moving the thermistor position which changes the interior temperature relative to the thermistor temperature which the control board cannot possibly know. Again, on an adjustable fridge there’s no reason to do that unless the max setting still isn’t cold enough.

In both, if the thermistor falls off they will over cool.

Thermostats on fridges with adjustable temp settings are pre-set at factory for specific temp range and calibrated for those temps based on OEM position of thermistor on fin.
Thermistor just senses the fin temp so when the pre-set temp is reach the thermostat shuts off 'heating'

Auto Temp Control uses the thermistor as the setting for temps.
Moving thermistor UP/Colder (warmer fin) thermostat continues 'heating cycle' until temp is reached .....longer heating cycles
Moving thermistor DOWN/WARMER (colder fin) thermostat continues 'heating cycle' until temp is reached.....shorter heating cycles
Overall affect is 6*F-8*F

Old-Biscuit wrote:
IF fridge uses an 'Auto Temp Control' then sliding thermistor Up/Colder or DOWN/Warmer
Sliding thermistor (UP/DOWN) on the fin can affect overall temp by few degrees IF the fridge model does NOT have adjustable temp settings

Doesn't have same affect on those with adjustable temp settings...those temp settings are pre-set and just use the fin temp as sensor for that pre-set temp

Hey biscuit, how can moving the thermistor not affect either model? The idea behind moving it is that different heights of the fin are at different temperatures due to the phase change of the coolant behind them. Regardless of user adjustable temperature settings, the control board perceives the temperature by reading that thermistor. The only difference between a adjustable model and fixed one should be the target temperature(s), not the sensing method.

I think the confusion happens because on the fixed temperature models, moving the thermistor is simply the only way to do it. Please help me to understand why, if my reasoning is wrong.

Been there - agree with Old Biscuit - likely culprit is failed thermistor. When the thermistor fails the refrigerator will revert to constant cool which will eventually freeze everything.

Thermistor is the temp sensor in the food compartment....that is what the thermostat uses to control fridge temp

Majority of fridge models will go into continuous cooling cycle when the thermistor fails (or falls off fin and hangs down)
Thermistor measures the FIN Temp---W/O that feedback the thermostat doesn't know food compartment is COLD.

Thermistor.....that is issue




IF fridge uses an 'Auto Temp Control' then sliding thermistor Up/Colder or DOWN/Warmer
Sliding thermistor (UP/DOWN) on the fin can affect overall temp by few degrees IF the fridge model does NOT have adjustable temp settings

Doesn't have same affect on those with adjustable temp settings...those temp settings are pre-set and just use the fin temp as sensor for that pre-set temp

If it’s worked fine in the past, it’s possible the thermistor has failed open. It’s thst little thing on the fins mentioned above. They are cheap to buy and plug in replaceable. Something like this, depending upon what model you have. https://www.amazon.com/Norcold-618548-Refrigerator-Thermistor-Assembly/dp/B077YX1JXR/ref=sr_1_9?ie=UTF8&qid=1537112308&sr=8-9&keywords=norcold+n621

Of course first make sure it didn’t somehow get knocked off the fin.

Raven52 wrote:
We have a Norcold 6 cu. ft freezer /fridge. Is 10 years old. The refrigerator was so cold that it blew the top off a can of pop. What could be causing this pls?

There an electrical control where you set the coldness in the refer. Called the eyebrow, it's either above the refer or in the middle of the two doors. You're probably already aware of that, and that lower numbers warm up the refer, higher numbers cool it further. Move that to the middle setting. Mine goes from 1 to 9, I usually keep it at 5.

Once you've set it for mid-range, open the refer (not the freezer) and look at those fins on the back wall. On the far right fin, there's a plastic device that can slide up or down on the fin. Slide it down. That should warm up the refer.

The thing is that it takes hours for settings like that to stabilize in the refer. If you don't have time or patience, you should just open the door to quickly warm it up for testing. Then let it cool down naturally for a couple hours, then measure the temp. Move the plastic slider up a bit to get it cooler if necessary.