We are new to the camping / RV world so please excuse any rookie statements I make. We love the camper but are learning there are a number of maintenance issues. Our Dometic runs well on shore power. The bottom of the tube heats up and there's a noticable difference in temp between the top and bottom of the tube.On LP, however, it lights with no problem and stays lit with a nice blue flame. However, the entire tube heats to the point of being very hot to the touch; no thermo difference between top and bottom.The fridge does not cool at all when on LP. I've inspected the board and it looks good - no obvious overheating or bad connections. I've inspected the flume from the bottom. The baffle is present and I do not detect any soot or debris in the tube.I appreciate any suggestions as to what to do next. I am mechanically inclined so not afraid to get into it deeper.

The boiler is heated from the outside with the electric heater inside a tube welded to the side. The propane flame heats inside the boiler. The normal operating temperature of the boiler should not exceed 350 degrees on either one. Unfortunately, the mfgs don't have a limit control as standard. https://www.rvrepairclub.com/article/how-absorption-refrigeration-works/

welcome. theres some good guys on here who will chime in on your problem. and if you need pro help call a rv tech in your area, they come to you, your rv won,t sit at the dealers lot for a month before they even look at it. also the rv tech will answer question you might have. mkost are very helpful.

Cooling Unit 'Perk Tube' is he boiler section where HEAT is transfered and boils the ammonia into hot vaporElectric element transfers that heat via conduction....element get hots, heats the element sleeve which is welded to perk tube and heats the ammonia inside \\Propane Flame generates heat which is absorbed by the flue baffle which then transfers the heat via radiationFlame should just reach up inside bottom opening of flue At top of flue should be a FLUE CAP/TOPIt slows the heat rising up from flame so baffle has opportunity to absorb the heat generated.W/O FLUE CAP heat rises/escapes to quickly...therfore less is absorbed and trransfered to boil the ammonia

You did good research. I doubt 1 out of 10,000 RV'ers would even know to inspect the Baffle to be there. IF they even knew they had one. The critical point since you seem to have done almost everything. EXCEPT-The LP pressure. THAT is critical to LP operation on a refer. Low LP pressure will still yield a blue flame. Also, Did you pull the baffle and did you clean out the flue tube the baffle is in? ANY rust or blockage around that spiral baffle will hinder flue temp operation. You need to state how old the RV/Refer is. Is it possible the baffle has rusted/corroded and is not as long as it needs to be? Doug

Thanks so much everyone! Especially love the diagram on how the unit works. Excellent information. The camper is a 2013 Vista. The Mfg date on the Dometic RM2551 is 2011.I have not pulled out the unit and inspected from the top down which is my next task. I did try to push the baffle upwards to see if there was any resistance which it wouldn't move.The flame does not reach the inside of the flue. It is a small blue flame that is about 1/4 to 1/2 inch high.

Dometic RM2551 fridge won't operate on propane | Good Sam Community

kjmaggart
Explorer
Sep 15, 2019
Ok; my flame doesn't look like that. It looks like the small, bright flames in the picture but doesn't create a plume of blue flame. Next thing is to check the pressure and make sure we are getting the propane necessary.

Thanks for an informative pic!
Old-Biscuit
Explorer III
Sep 15, 2019
Flame should be strong BLUE and reach just inside the flue

Remove burner assembly
Clean burner tube/slots
Clean orifice (soak in alcohol...then air dry
(***NO POKING anything thru OR High Pressure Air)

If flame still small.....
LP System Pressure S/B 11"WC with at least 50% of other propane appliances in service
Test port on fridge gas valve for connecting Manometer
kjmaggart
Explorer
Sep 15, 2019
Thanks so much everyone! Especially love the diagram on how the unit works. Excellent information. The camper is a 2013 Vista. The Mfg date on the Dometic RM2551 is 2011.

I have not pulled out the unit and inspected from the top down which is my next task. I did try to push the baffle upwards to see if there was any resistance which it wouldn't move.

The flame does not reach the inside of the flue. It is a small blue flame that is about 1/4 to 1/2 inch high.
dougrainer
Nomad
Sep 15, 2019
You did good research. I doubt 1 out of 10,000 RV'ers would even know to inspect the Baffle to be there. IF they even knew they had one. The critical point since you seem to have done almost everything. EXCEPT-The LP pressure. THAT is critical to LP operation on a refer. Low LP pressure will still yield a blue flame. Also, Did you pull the baffle and did you clean out the flue tube the baffle is in? ANY rust or blockage around that spiral baffle will hinder flue temp operation. You need to state how old the RV/Refer is. Is it possible the baffle has rusted/corroded and is not as long as it needs to be? Doug
Old-Biscuit
Explorer III
Sep 14, 2019
Cooling Unit 'Perk Tube' is he boiler section where HEAT is transfered and boils the ammonia into hot vapor

Electric element transfers that heat via conduction....element get hots, heats the element sleeve which is welded to perk tube and heats the ammonia inside \\

Propane Flame generates heat which is absorbed by the flue baffle which then transfers the heat via radiation

Flame should just reach up inside bottom opening of flue
At top of flue should be a FLUE CAP/TOP
It slows the heat rising up from flame so baffle has opportunity to absorb the heat generated.
W/O FLUE CAP heat rises/escapes to quickly...therfore less is absorbed and trransfered to boil the ammonia
midnightsadie
Explorer II
Sep 14, 2019
welcome. theres some good guys on here who will chime in on your problem. and if you need pro help call a rv tech in your area, they come to you, your rv won,t sit at the dealers lot for a month before they even look at it. also the rv tech will answer question you might have. mkost are very helpful.
DFord
Explorer
Sep 14, 2019
The boiler is heated from the outside with the electric heater inside a tube welded to the side. The propane flame heats inside the boiler. The normal operating temperature of the boiler should not exceed 350 degrees on either one. Unfortunately, the mfgs don't have a limit control as standard.

https://www.rvrepairclub.com/article/how-absorption-refrigeration-works/

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Dometic RM2551 fridge won't operate on propane

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