Dometic RM 2353 Three-Way Fridge Not Cooling

[joglen]

Joglen here. Enjoying retirement with wife (4th season) in well maintained 2004 190 Roadtrek. We are 3rd owner beginning 2023. Need advice with old dometic model RM 2353 Three-way fridge please. Most likely original to the van. I have some mechanical skill but not strong in electrical knowledge. On backside of fridge it heats up on both AC power and propane but no cooling on inside coils during the last trip. Very little info online for an old fridge like this. Thanks

 

[Tamw]

Try checking that the rear vent airflow isn’t blocked. Run it overnight with a thermometer inside. If there’s no temp drop or you see yellow residue, the cooling unit is likely done.

 

[RT-NY]

As Tamw says, the yellow reside would indicate that the coils in the back have sprung a leak, which means you would have to replace the coils (which isn't actually that hard to do, though it is not cheap). It is also possible that the coils are blocked inside, and some people recommended "burping" the fridge (just search online) as a possible fix, though I am skeptical of that. You can check if it is blocked by measuring the temperature difference higher up on the coils and below at the bottom of that assembly.

First try ensuring that the fridge is 100% level and putting a thermometer with a remote probe in the freezer. These old fridges can become very, very sensitive to being out of level but still work fine. If it isn't cooling at all then take temperature measurements at various places on the coils in the back and post the temperature readings here.

 

[ChicagoTom]

Ex HVAC, many years ago, but I've worked on all types of cooling units. As others mentioned, greenish, yellow on the coils and I would trash it. Some have replaced that section, but IMO, just replace the fridge. I replaced, like for like RM2354, and mine stays ice cold until around 100 degrees, then I know not to put perishables in the fridge section. (The freezer always stays cold). I remove the clip on this fan and you can just lay it up or down on the shelf. Amazon.com

 

[joglen]

UPDATE All good I discovered the problem and its fixed!!
Went to YouTube and Darren from MyRVworks.com has a short video titled VENT LEAKER or BLOCKAGE that explains very well what RT-NY suggested it could be. Yes - it was blocked. On our last trip the van was parked nose down for 4 days then the fridge suddenly quit. When we got back I leveled up really well and success.
Thank you all.

 

[engnrsrule]

No one has mentioned this but absorption fridges are not effective if the ambient temp is above 90°. I replaced a 2005 Dometic that failed in 2020 with a RM 8505 which worked ok when below 90°. However we have taken to summer trips in the south. I have improved our battery (up to 300ah Lithium) and added 290w of solar. So we just swapped to a compressor fridge which has no trouble in the heat. The RM 8505 is currently for sale if you are interested.

I should add that I did improve the RM 8505 performance through the use of external and internal fans. I had 4 5" computer fans on the exterior top vent set up to exhaust the rear cavity, and 2 small computer fans inside, which wired to the units 12v. Parking in hot weather with the fridge on the shady side helps. See pictures.

 

[RT-NY]

UPDATE All good I discovered the problem and its fixed!!
Went to YouTube and Darren from MyRVworks.com has a short video titled VENT LEAKER or BLOCKAGE that explains very well what RT-NY suggested it could be. Yes - it was blocked. On our last trip the van was parked nose down for 4 days then the fridge suddenly quit. When we got back I leveled up really well and success.
Thank you all.

Glad to hear it. This problem is potentially progressive but managable -- the more these kind of fridges are run out of level, the worse it might get (and front to back out of level is worse than side to side). I always keep a thermometer with a remote probe in the freezer and use just a standard bubble level. I have developed a sense of what works, so most of the time it's all easy. But, if I have no choice but to park out of level for a time but still need to run the fridge, I keep an eye on it. If it stops cooling I can usually just start the engine and move the van forward and back a bit with some slightly sharp stops in order to shake up the fluid in the coils and it will start again. Not ideal, I suppose, but it works for me!

 

[joglen]

Glad to hear it. This problem is potentially progressive but managable -- the more these kind of fridges are run out of level, the worse it might get (and front to back out of level is worse than side to side). I always keep a thermometer with a remote probe in the freezer and use just a standard bubble level. I have developed a sense of what works, so most of the time it's all easy. But, if I have no choice but to park out of level for a time but still need to run the fridge, I keep an eye on it. If it stops cooling I can usually just start the engine and move the van forward and back a bit with some slightly sharp stops in order to shake up the fluid in the coils and it will start again. Not ideal, I suppose, but it works for me!

Good advice regarding the remote thermometer. Funny thing about moving van around with sharp turns and stops is sometimes Ive needed to do this on ours when we fuel up in hot weather (it seems). I pull up to the pump knowing its near empty and can only get a few gallons in it before pump clicks off. I leave gas pump and drive around the gas station like a slightly aggressive driver and it works. Some sort of vapor lock in the fill house or....???
FYI - This well maintained Chevy 3500 Road Trek is our first RV and we paid a fair price for it 3 yrs ago. Been loving it and using it! We hesitate to upgrade because its been so reliable. But at the same time hesitate to sink too much money into this old beast (2004). So your good advice is very much appreciated. Thanks again

 

[joglen]

No one has mentioned this but absorption fridges are not effective if the ambient temp is above 90°. I replaced a 2005 Dometic that failed in 2020 with a RM 8505 which worked ok when below 90°. However we have taken to summer trips in the south. I have improved our battery (up to 300ah Lithium) and added 290w of solar. So we just swapped to a compressor fridge which has no trouble in the heat. The RM 8505 is currently for sale if you are interested.

I should add that I did improve the RM 8505 performance through the use of external and internal fans. I had 4 5" computer fans on the exterior top vent set up to exhaust the rear cavity, and 2 small computer fans inside, which wired to the units 12v. Parking in hot weather with the fridge on the shady side helps. See pictures.

 

[joglen]

Thanks engnrsrule
If you happen to be traveling towards Panama City Beach FL (our home) maybe we can negotiate a deal to unload your RM8505. Just a thought.
We also spend extended time in Satallite beach, FL where son and daughter in law live if your travels take you down that side of FL.
Cheers, JO