Refrigerator settings

[dadstoy]

Summer temps up north can be pretty brutal. Last couple of weeks and upcoming couple of weeks the temps were and will be between 100 - 105 degrees. A month ago it was 115.

My Dometic refrig works ok, but I would like it to be colder. The freezer works great.

I'm trying to understand the relationship between adjusting the thermistor position on the fins inside the refrig and the 5 position switch on the control panel.

I understand the thermistor simply reads ohms which changes as the thermistor is moved up or down on the evaporator fins. Higher on the fins means colder. Lower means warmer.

I understand that the 5 position switch on the control panel adjusts the time that the heater is on. Position 1, heater is on less time, position 5, heater is on for a longer period of time. The heater will cycle on and off for a set amount of time depending on the position of this switch. Once the heater switches off, the control board checks the resistence of the thermistor.

Thats all good, but what is the relationship between the two? I've pushed the thermistor as high on the evaporator fin as possible for a colder temp. But setting the 5 position switch to position 5 doesn't necessarily make the refrig colder. Its hard to determine, but I think with my refrig, it gets colder on setting 3 or 4.

So how does a higher or lower setting of the 5 position switch, which determines how long the heater is on before it turns off and reads the thermistor affect the temp of the refrig? I'm confused?

[ITSNO60]

Don't know what model you have but I have been doing a lot of in-depth study of the 8xxx series. I do not see where the temperature control is accomplished through time, my understanding is that it is accomplished thermostatically unless the thermistor fails then it defaults to a timed value of 45 mins on and 14 min off. On older Dometics the default may be always on, I don't know.
Where have you seen that the temperature setting is time controlled? Maybe so on the older fridges?

I am in the process of tinkering with the thermistor now that I have completed all my installation corrections and my Fridge Defend and cooling fan mods. I may go with Fridge Defend's adjustable thermistor kit.

Check out this link, there are free manuals for Dometic, there is even a Dometic training guide. https://myrvworks.com/manuals/

[uncle_bob]

Hi

Never say always but ....

Moving the thermistor *down* makes the fridge section colder. Moving it up makes the fridge area warmer.

Turning the control dial up means burning more propane and making both the fridge and freezer colder.

Bob

[ITSNO60]

Originally Posted by uncle_bob

Hi



Moving the thermistor *down* makes the fridge section colder. Moving it up makes the fridge area warmer.



Bob

That is opposite of what I have found. The fins are colder on the bottom and moving the thermistor up to the warmer part makes the fridge colder.

[dadstoy]

Everything I have read and watched so far describes moving the thermistor up for colder and I have verified that on mine. I have a RM2820 and it is 10 years old.



The following youtube video is the only information that I have found to date that describes the thermistor and the 5 position switch.


https://youtu.be/bY7cy4Kf3VQ


Brian, thanks for the document library link!


Thanks!

[Daquenzer]

The big problem with the refrigerator is circulation. I bought a cheap little fan for the refrigerator that runs on batteries. It does help circulate the cold air. You can get a fan system to hook onto the back. It costs quite a bit more, but probably works better.

And yes moving the number to 5 makes it colder. That’s how it works on mine.

[1StreamDream]

I have the same understanding and observations, thermistor high results in colder, thermistor low results in warmer, but I cannot find anything in my set of docs (published by Dometic) that confirms that relationship.

[uncle_bob]

Hi

Which way is up?

Bob