I have an older Norcold 1200-series unit with the cooling unit recently replaced. Always keep it level. I recently installed one of those wireless temp read-outs with remote sensors that go in the freezer and fridge. It seems to be a device whose main purpose is to give me something new to worry about. :)My fridge normally gets to -3F in the freezer and 31F in the fridge on the highest setting. I had an issue this past weekend where the fridge wouldn't get any colder than 41F all weekend. Freezer was 24. I was thinking that my cooling unit was going bad.I did notice that there was ice on the fins inside the fridge. I turned the fridge off and on a couple times to avoid the Norcold 49-hour defrost cycle and the inevitable warming that it causes. My question: Does the ice on the fins somehow insulate it and prevent it from cooling down?When I got home, I let it defrost and when all moisture was gone from the fins, I started it back up again, and it was cooling as it normally did.Any idea what is causing the warmer temperatures when in use? I know that opening the fridge does cause significant warming, but I expected it to cool back down overnight, which didn't happen.Any good way to prevent moisture on the fins? I heard that installing fans might help with this.Thanks for listening :)Wayne

Like you I turn mine off every two days to stop the defrost cycle and move this fan to a different location on the fins to defrost the ice. Yes ice on the fins will lower the cooling slightly as the air is getting to 31+ degree ice instead of 27- degree fins.Was it hotter out than normal when it would not cool as well? Was that side in the sun all day? Are both outside fans working? Does not take much to have the inside temp go up. You can have another thing to to watch by holding both the Mode and Temp buttons down until you get 88 , Then press Mode three times to get a readout of the fins temp. I'm in the process of replacing mine with a home refer.

Thanks for the info. I'll take a look into that fan. The temperature was in the low 90s, but it was the same temp before and after when the fridge was cooling properly.The only difference that I could see was ice on the fins, and wondered if that was causing the issue.

The thermistor measures fin temp which is what thermostat controls too....fin temp is roughly 10*F lower than food section air temp.Ice up fins.......thermistor is reading COLD temp so thermostat is satisfied (false reading)Circulating fan(s) in food section will help keep fins from icing up.

Old-Biscuit wrote:Ice up fins.......thermistor is reading COLD temp so thermostat is satisfied (false reading)I don't think that's the case here. According to the Norcold diagnostic-mode readout, The thermistor temperature was in the high 20s, low 30s when usually its < 20 .. I would think that if the ice was making the thermistor colder, then the thermister temp would be normal.This is why I was thinking that the ice was actually preventing cooling instead of masking the thermistor temp.

ICE is a insulator. It keeps the lower section from cooling DOWN correctly. Frost/thin ice on the fins is normal. The 48 to 54 defrost cycle will NOT cause a hi rise in temp inside the refer. All that defrost cycle does is shut down the refer for 2 hours and that allows the fins to thaw and drain off the ice/moisture. This will not cause the FREEZER to rise in temp. Since you went up to 24 degrees that points to something else. When the CU was replaced, did they replace the rear fan Tstat and the rear fans also? IF the 1200 is more than 5 years old, then the fan tstat and the fans should be replaced if the Refer is going to be pulled. This is a preventative measure and also that is about the life span of the tstat and fans. Doug

Norcold Fridge - Ice on Fins | Good Sam Community

Ivylog
Explorer III
Jun 09, 2015
Like you I turn mine off every two days to stop the defrost cycle and move this fan to a different location on the fins to defrost the ice. Yes ice on the fins will lower the cooling slightly as the air is getting to 31+ degree ice instead of 27- degree fins.
Was it hotter out than normal when it would not cool as well? Was that side in the sun all day? Are both outside fans working? Does not take much to have the inside temp go up. You can have another thing to to watch by holding both the Mode and Temp buttons down until you get 88 , Then press Mode three times to get a readout of the fins temp. I'm in the process of replacing mine with a home refer.
Wishbone51
Explorer
Jun 09, 2015
Thanks for the info. I'll take a look into that fan. The temperature was in the low 90s, but it was the same temp before and after when the fridge was cooling properly.

The only difference that I could see was ice on the fins, and wondered if that was causing the issue.
Old-Biscuit
Explorer III
Jun 09, 2015
The thermistor measures fin temp which is what thermostat controls too....fin temp is roughly 10*F lower than food section air temp.

Ice up fins.......thermistor is reading COLD temp so thermostat is satisfied (false reading)

Circulating fan(s) in food section will help keep fins from icing up.
Wishbone51
Explorer
Jun 09, 2015
Old-Biscuit wrote:
Ice up fins.......thermistor is reading COLD temp so thermostat is satisfied (false reading)

I don't think that's the case here. According to the Norcold diagnostic-mode readout, The thermistor temperature was in the high 20s, low 30s when usually its < 20 .. I would think that if the ice was making the thermistor colder, then the thermister temp would be normal.

This is why I was thinking that the ice was actually preventing cooling instead of masking the thermistor temp.
dougrainer
Nomad
Jun 09, 2015
ICE is a insulator. It keeps the lower section from cooling DOWN correctly. Frost/thin ice on the fins is normal. The 48 to 54 defrost cycle will NOT cause a hi rise in temp inside the refer. All that defrost cycle does is shut down the refer for 2 hours and that allows the fins to thaw and drain off the ice/moisture. This will not cause the FREEZER to rise in temp. Since you went up to 24 degrees that points to something else. When the CU was replaced, did they replace the rear fan Tstat and the rear fans also? IF the 1200 is more than 5 years old, then the fan tstat and the fans should be replaced if the Refer is going to be pulled. This is a preventative measure and also that is about the life span of the tstat and fans. Doug
Trackrig
Explorer II
Jun 09, 2015
Look at one of these fans. It covers the whole width of the cooling fins on the 1200 so it keeps the whole thing defrosted plus it provides a lot of air circulation in the refer.

If you buy one, per someone's advice on the forum, you can run the power wire for it to the rear through the drain tube so you don't have to worry about putting a hole through the back of the refer - worked well. It's best to install it in a warm refer. Since I was in there working, I changed the thermistor at the same time to a new and adjustable one. It's easier to change the thermistor before in stalling the fan.

And as noted above, try to park with the refer out of the strong mid day sun.

Bill
turbojimmy
Explorer
Jun 09, 2015
Old-Biscuit wrote:
The thermistor measures fin temp which is what thermostat controls too....fin temp is roughly 10*F lower than food section air temp.

Ice up fins.......thermistor is reading COLD temp so thermostat is satisfied (false reading)

Circulating fan(s) in food section will help keep fins from icing up.

I did this to my old Norcold after I replaced the cooling unit. Everything stays colder and evenly cold now, and there's limited ice on the fins. I do have to move the fan around sometimes, particularly if people have been opening and closing the door a lot. Ice will start to accumulate where the fan isn't.
wilanddij
Explorer
Jun 10, 2015
I had problems with ice on the refer fins until I found the auto defrost switch and turned it on.
Kit_Carson
Explorer
Jun 10, 2015
wilanddij wrote:
I had problems with ice on the refer fins until I found the auto defrost switch and turned it on.
Where is the switch located?
Ivylog
Explorer III
Jun 10, 2015
The OP has a NoCold 1200... there is not a switch. Smaller rigs (32' & Class C) with smaller refers may have a switch.

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