Dometic RM2852 not cooling but has flame...

HERE is Service Manual

Check out pg. 13 paragraph E

Be careful rattling the baffle. Before I knew it was in there, I rammed a bottle brush up the flu pipe and pushed the baffle up, that caused big problems. I had to unbolt the fridge and slide it forward to get to the top of the flu pipe to reset the baffle in the correct spot in the flu.

Anyways, I have an old rm2820 that I have to coax every trip to get it to run. The flu pipe is notorious for dropping rust in the burner tube. Get compressed air, and blow out the burner tube (I keep a straw in the fridge hatch to blow it out.) I bet bouncing down the rough road dislodged a lot of rust. I even had a rust flake drop on the igniter and short it out, took a while to figure that one out.

Anyways, the burner tube is where the flame comes out. Observe the size of the flame (I look at the Blue part that comes out of the slots in the burner tube.) Mine burns normally about 3/16 of an inch high, any lower and rust is likely blocking the slots. Blown it out, and see if the flame gets larger, if so in a few hours you should get some cooling.

A last thing to check is the orifice, it's the brass nozzle where the propane is blown into the burner tube. Soak this in rubbing alcohol, and blow out with compressed air (do not stick anything in the orifice as you could enlarge it.)

The baffle, burner tube, and orifice all work together to get the correct amount of heat. I'd try blow out burner tube first.

Good luck.

Look in the flame compartment for debris.
Then use a flexible wire, like an old coat hanger. Stick it up in the stack tube that is right above the burner flame area. There is a baffle 3-5 inches up in it. Rattle it as there could be debris blocking the stack tube.

I just ordered a new one for mine that quit after 4 years. I got it from RV Cooling Unit Warehouse cause it's over built , guaranteed 5 years and really reasonable. And using their videos you can change it out yourself.