Dometic refrigerator not cooling properly

[Ragman]

We have a Dometic "New Dimensions" Model NDR 1292, side by side refrigerator/freezer. It was manufactured about 2000-2001.

Recently, on a few occasions, we have experienced cooling problems where the refrigerator temperature would fluctuate anywhere from 32 degrees up to 48 degrees. It doesn't seem to matter what setting we have the "cooling" on, it still happens. It makes no difference whether running on electric or gas.

On this trip, we have been stationary for the past three months. A little over a week ago we noticed that the temp was 58 degrees and remained there for about three days; then went back down to around 40. Again, three days ago, it went back up to 58 for a couple days. Now it is running at around 46.

Our friends, who have been camping with us, have the identical refrigerator and they do not experience this problem.

Anyone have any idea what could be wrong? And how to correct the problem. I would appreciate hearing from you.

Happy Trails,

Larry

[clyon51]

We had similar symtoms on our new to us Dometic RM 3862. We found out we were not closing the doors until they "snapped" shut. We must have been thinking those door seals were magnatized I guess

Anyway, I'm sure this isn't your problem. It sounds like the thermostat could be getting bad. I suppose it could be the cooling unit, which would not be good. Sorry I couldn't offer anything specific.

[Wanabee FTer]

Here is a link to a great blog about RV refridgerators, it may help you diagnose the problem. Understanding Your RV Refrigerator

[GaryKD]

Hi Ragman,
I have the same refer as you do. Your description eliminates fuses and thermistor as the problem. A blown fuse would be a constant problem. A bad thermistor almost always results in too much cooling. However, a poorly positioned thermistor could lead to erratic cooling. The OP also just about eliminates air circulation behind the refer and in the chimney. My comments will focus to inside the fridge. Consider the following:
1. It takes about 1 hour for the refer to recover from opening the door for 1 minute.
2. Do you have fan(s) inside the refer to circulate air?
3. Does the temp go up for the days after the recently purchased groceries are loaded in it?
4. The temp is almost totally dependent on air circulation inside the refer. Is the high temp coincident with the refer being full of food?
5. There is a plastic slider on a cooling fin (in the rear of the refer) that has the thermistor attached to it. Determine where the thermistor is located in the slider. Make sure the thermistor is on the designated cooling fin (far right fin). The thermistor works best if located around where the designating label might be on the side or rear wall of the unit. Move the slider up to lower the temp. However, under no circumstances should the thermistor loose contact with the cooling fin. This will cause the erratic temps you are describing.

If you want to check the thermistor:
1. On the outside back of the refer there is a circuit board.
2. After removing the cover remove the two thermistor leads from the circuit board.
3. At room temp (70-75 F) there should be about 3K ohms across the leads.
4. Place the thermistor in ice water for 5 minutes. There should be about 9K ohms across the leads. A high (high like 50K ohms) reading indicates a bad thermistor. However, this would lead to over cooling.

Set on #4, my unit will hold 32F in the fridge when about 1/4 full. When full it will hold 38F.

[Ragman]

Thanks to all. Gary, really appreciate the information you have given us. This is our fourth motorhome since 1971 and pretty familiar with the problems with R V refrigerators.Was not familiar with how to check the thermostat. I have always performed my own maintenance, but very slow when figuring out electrical problems. I will give it a try, thanks again
Larry

[Ragman]

Just check the refrigerator and it was 40°. It and has been on electricity since yesterday around 3:30 PM when we arrived. But I don't think it's a gas problem. We will be here for two weeks , will just wait and see what happens. Might have to put a call into the RV Dr. if we can't figure it out. Thanks again to all.
Larry

[PhilipMorris]

I am having the same problem with my one year old Side by side. The local RV shop imtake it to says it was not installed properly and had too much space behind it pt draw and cool properly. They fixed that problem and it still cools erratically. Cooling best afer it is plugged in for a few days but starts to heat up as we travel down the road. I don't remember seeing a thermistor slide on mine so I will check as that could be the problem.

Thanks for the info.
Philip Morris

["007"]

Find a 12v fan or 110v fan when parked in camp ground and aim it up through your vent area in rear of fridge.
Check your box temps after a few hours of use, may find your temps have dropped.
Many have install extra fans because of the heat this summer.
The vent area up through the roof vent should be clear to get the heat out of there for the fridge to work efficiently.
If you do a search in this forum there are many threads on better cooling of your fridge cooling units.

Welcome to irv2 Phillip.

[westie0506]

Originally Posted by Wanabee FTer

Here is a link to a great blog about RV refridgerators, it may help you diagnose the problem. Understanding Your RV Refrigerator

Link is not working - need refrigerator help! Thanks

[Wanabee FTer]

Originally Posted by westie0506

Link is not working - need refrigerator help! Thanks

Sorry about the dead link, looks like he removed the free info and is now selling books

What kind of trouble are you having?

[Jack1234]

You might want to look at popping one of these cube fans in your fridge ....will help to circulate air and keep your cooling fins free of frost build-up. You may also want to consider an aux, fan for the back of the fridge.

Good luck

[westie0506]

We had a door issue - the flap on the left side is not moving up to seal right door properly - manually pulled it in place and the temperature starting dropping to within range immediately. Whew!! Disaster averted....

[GFDOUCET]

Can anyone tell me what the degrees on the refrigerator should be? I know 55-60 can't be right with the setting on as cool as could be!

[flaggship1]

Originally Posted by Rushmore2011

Can anyone tell me what the degrees on the refrigerator should be? I know 55-60 can't be right with the setting on as cool as could be!

Above 32 so as not to freeze your veggies and fruit - 35-38 degrees is recommended.