Dometic RM2551 too cold...

[ryancousins]

I checked the thermistor. My fridge was around 5 degrees F but may have gone up to around 12-15 degrees since I had the door open. At that point my meter read about 8.5 K Ohms. I then pinched the thermistor w my fingers for 30 seconds or so and then it read around 5 K Ohms. I?m not sure if these are appropriate amounts as I?ve seen different charts and figures for what they should be for dometic fridges. I tried moving the thermistor around to different spots with no luck. Obviously the thermistor is functioning but perhaps it?s out of range? Otherwise what else should I look at?

 

[Henry J Fate]

Here is the service manual.

http://techsupport.pdxrvwholesale.com/wp-content/uploads/2017/09/Dometic-Diagnostic-Service-Manual-RM2551.pdf

It could be a board problem. The thermistor seems to be in the correct range. I am guessing that the fridge is not shutting down. An easy way of monitoring a cycling fridge is on propane. Usually you can hear it or see it on or off. Usually you would need a meter to monitor the 110 volt heater. If the fridge stays on or continues the same problem in both modes, then it will either be the thermistor or the board.

 

[Gary RV_Wizard]

Absorption fridges lack internal air circulation, so have notoriously uneven temperatures.  Have you measured in different spots?  And are you measuring with a thermometer immersed in a cup or glass of water?  You can't get consistent and valid readings in the air - the water helps stabilize readings.

 

[ryancousins]

I have two different thermometers in the fridge in different places and they both tend to agree with one a other but I could try moving them around. I don?t have the thermistor in water; I?ll do that. I used the fridge recently and everything inside froze solid after one day, regardless of its location on the shelves or in the door. So even if there is a lot of variation in temp, even the warmest temp is way below freezing.

I did try moving the thermistor last night. It?s in between the fins, rubbing up against them. It?s at 11 degrees F, now. But now sure how to find a colder spot than directly touching the fins.

 

[Henry J Fate]

Definately check the thermistor as described in the service manual. Also check to see if the unit ever cycles off.

 

[Rene T]

Gary wanted you to put the thermometer in a cup of water.

 

[ryancousins]

Oh, thermometer. Didn?t read carefully. Got it!

 

[Drewd]

Just snip the tip and you can install an adjustable thermistor.  https://www.snip-the-tip.com/cgi-bin/articca.cgi