Dometic refrigerator not cold enough

[Tomjp]

Recently my Dometic RM2551 has not been able to get colder than about 50 degrees with the freezer at about 8. I have fiddled with the thermistor sliding it all the way up and no help.
Has anyone had experience installing the Dinosaur Electronics THERMADJUSTERDOMETIC Dometic Variable Thermistor Adjuster?

[Turbulence]

Have you tried running it on propane? We had the same issue running on electric when it was hot. I tried extra fans and other things - but nothing worked except for running it on propane - which works perfectly even when it's 90+ outside.

Thanks,
Scotty

[GCinSC2]

Dual or single door?

If dual might be interesting to do the classic dollar bill door seal test.

Do you have an IR temp gun? If so read the temp just above the heating element area of the chimney. I see 95+ deg F when I check mine.

No IR temp gun, good item for the truck door pocket.

Gary

[Tomjp]

It has been extremely hot so maybe that’s the issue. And I mostly run it on electric so perhaps I can try propane.
And it’s just one door. I don’t sense any leaks around the door but of course we’re talking just a bare hand test!
Thanks for the suggestions.
I doubt I’ll do the adjustable thermistor gadget but I may put in a new thermistor cable.

[Mollysdad]

You should have an outside vent. Open that door and see if something is blocking the airflow. I once had a wasp nest the size of a football. Also try a small electric fan outside in that space. Push the air up. There should be an outlet behind the fridge (for the fridge)

[GCinSC2]

If you’re handy with a multimeter the thermistor can easily be tested. Dometic published a temp vs resistance chart.

[vwii]

Our rig was supposed to come with fans behind the fridge but didn't. We added two fans with a temperature sensor switch, and improved refrigerator performance significantly. Even in Phoenix 100+ degree temperatures we can get 40 or so fridge temps. Works better with electric (rather than propane) and definitely works better if the trailer is level.

[Josephine517]

We added circulating fan inside the refrigerator, added exhaust fans outside We run on propane when temperatures are above 80 degrees. Upper 80 degree temperatures the only way for us to keep refrigerator in the food safe zone is ice in a quart size freezer bag placed in the refrigerator section. Our last trip every day was above 85 with the 5 days in the mid 90s. Our refrigerator stayed close to 32 degrees during the day and below freezing at night. Our ice lasted the 10 days of our trip and only a small portion was melted. Also the ice is a huge help for quicker refrigerator recovery when opening the refrigerator. Our travel home outside temperature got to 101 with 104 inside the trailer, the refrigerator held a steady 36 degrees. A small bag of ice is a low cost old school solution but works amazingly well and removes the worry.

[GetawA-S]

Tomjp,
The first fridge on our 2019 22 Sport (Bambi) was so bad the dealer replaced it. (The trailer was essentially new, but Dometic blew us off as second owners.)
We had some performance issues early on with our 2020 23 FB FC; the addition of a 6" vent van (with a cool, spaceship looking blue LED on it for some reason) right inside the upper access door has pretty much eliminated any problems. The temperature control on the A-S supplied 3" wafer fan installed lower down had failed. I wired the new fan in parallel and cut out the temperature control. The little bit of fan noise is less irritating than having the backside fan cutting in and out.
IR thermometer is a great tool, also for battery checks.
We also have a dual transmitter thermometer (freezer and fridge, it appears from your posts you already have one) that we use to track performance.
We try not to overstuff the fridge (Oh, look Honey, there's a farmers' market!) and the male partner is not allowed to rummage for stuff (beer is always in the same place).
Good luck!

[lemley]

This does not cover your specific model but it has the basics on troubleshooting.

https://rvrefrigeratorrepair.com/wp-content/uploads/2016/07/Dometic-Service-RM2612.pdf

Bottom line is that absorption fridges struggle in high heat. I’m in the process of adding fan assist to the top of the chimney on mine.

[CruizinDux]

if you search "refer not cooling" you'll have reading material for a lifetime.

However here are three recent threads (and one very old one) that hopefully will be educational. Understanding the working process and components of an absorption refer was an eye opener for me.

https://www.airforums.com/forums/f42...cb-230593.html

https://www.airforums.com/forums/f42...ml#post2604435

https://www.airforums.com/forums/f42...it-232279.html

and not to be forgotten ...
https://www.airforums.com/forums/f42...lly-11811.html


Please understand that TT set ups are different so opinions while applicable to one are not necessarily applicable to others. Key is the venting. Some like mine have to horizontal vents (upper and lower) and some have a lower and roof).

What IMO also needs to be understood early on is that AS often (IMO) does not follow Dometic specs re the installation re vent locations relative to the cooling fins and insulation on top and the sides.

Aside from the wasp possibility's, it all boils (so to speak) down to heat in the burner tube (propane ~ check flame and orifice or Ele ~ Check element), air flow over the tubes and exhausting from the exterior refer compartment, the flow of ammonia and water (??) thru the tubes (not crystalized and {maybe partially} blocked from overheating) and condensing fins.


As GCinSC2 mentioned the thermister is easy to check with a meter. You can search for the chart. I'll post if I can find it. (See attached Dometic-Thermistor-R-Value-Refrigerator) The thermister should be in the upper fight corner at the top of the fins for the coldest setting.

Second are the fan(s) running assuming you have one. If not is the switch on? Maybe the refer stat went south and the fans are not coming on. You can jump the stat with a paper clip to see if it's getting power.
Third is the Refer level as can be (Front to back) ( it and the TT often not the same)

Third, is could be the board, but that's no where near being in my lane to comment other that say Dino Board.



Note differences in Propane vs ele.


Is the freezer close to 0 while the refer is in the 40's and above?

How packed is the refer. allow for vertical airflow within?

Lastly here are a couple of utube diagnostics vid's

https://www.youtube.com/watch?v=IT_5HGe4q-k

https://www.youtube.com/watch?v=2aE_4SuljE4

Bottom line there are no quick answers, only an evaluation process and possible replacement of things that effect the units ability to keep the beer cold.

Good luck

[1970 Safari]

Just got back from the Grand Canyon, both North and South and my Fridge worked the best ever in the high temps (80 - 90 degrees). I had 17 lbs of ice in the freezer and 7lbs in the refrigerator. First time I ever tried it and the temps were 32 at nite (0f course it had cooled off outside also) and 40 or so daytime on the hottest days.

We do not carry a lot of frozen stuff so the ice filling the freezer really did work, even partially froze the wifes water bottles for the first time.

I do run 2 fans in the vent and a small "double fan" (computer fan set up) in the refrigerator compartment. I have been thinking about lithium and 12 volt compressor fridge but I might be changing my mind..... A LOT less cost to buy ice......

[lemley]

In the topic of ice assist…. I’ve found it useful when camping in hot weather to pack frozen water bottles. Lately I’ve been putting four in the reefer to give it a boost after packing and four in the freezer for a boost during the trip. They work quite well to drop temps quickly and also provide a cold refreshing drink later.

[CruizinDux]

Originally Posted by lemley

This does not cover your specific model but it has the basics on troubleshooting.

https://rvrefrigeratorrepair.com/wp-...ice-RM2612.pdf

Bottom line is that absorption fridges struggle in high heat. I’m in the process of adding fan assist to the top of the chimney on mine.

Hey Bob, a huge thanks for this link. I've talked and corresponded directly with dometic and have never seen nor been offered this service document! I googled for my 2451 and viola'. What a 👍 resource.
Thanks!

[Foiled Again]

Hi. Just figured out a 2 month ordeal with my RM3762RBX refrigerator - 2012 25' Eddie Bauer. The cooling unit definitely hemmoraged ammonia and had to be.replaced, but the new Amish unit barely worked and was replaced under warranty after many tests. The replacement got the freezer cool, and did nothing for the refrigerator. The techs tried a new thermistor and a new control card. No Joy.
They spent 2 hours trouble shooting everything with Dometic, who recommended "hard wire everything" Only things that had not been tested were the light in the refrigerator and the switches in the freezer - on/off, gas/electric and temp 1 2 3 4 5.

And the techs (attaboy to Toy Doctor in Dade City, FL) bypassed the thermistor, control card, and freezer switches and COLD COLD COLD. 11 years of fulltiming - I guess the switch or its wiring failed. A new one Monday and I should be.back to normal.

Ironically this will probably turn out to be the least expensive part. I will post on a new thread, simply because these switches in one form or another are going to be on all Dometic 2 way refrigerators.

We may all eventually convert to compressor refrigerators eventually... but a switch replacement could buy another 5-10 years and the compressor ones are back ordered 2 years right now.

[CruizinDux]

F/A , that is great news. I'm not sure if you're talking about 3 separate switches, or board switches that are part of the new dino board. I'll watch for the new thread.

[Foiled Again]

Originally Posted by CruizinDux

F/A , that is great news. I'm not sure if you're talking about 3 separate switches, or board switches that are part of the new dino board. I'll watch for the new thread.

The three ganged together middle top of my freezer.

[CruizinDux]

Very interesting, thanks. Who would have thunk it!

[starkruzr]

Originally Posted by Mollysdad

You should have an outside vent. Open that door and see if something is blocking the airflow. I once had a wasp nest the size of a football. Also try a small electric fan outside in that space. Push the air up. There should be an outlet behind the fridge (for the fridge)

A cute thing I found out when I went looking for this was that the faceplate for this socket had a fake socket below the real one. Literally plastic molding that looks like a socket but blocked holes for conductors.

[Ky76Argosy]

8 degrees freezer sounds plenty cool, am I missing something?