Coast Resorts Open Roads Forum: Tech Issues: Dometic fridge RM2652 tripping thermal sensor


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rvman69

philpot

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Posted: 06/12/23 07:02pm

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Yeah I knew he was talking about the 120 volt element. I just wanted to make sure. Which after I typed it I was like no way it would matter. You know there is no way every outlet in these camp grounds are wired correctly. Thanks

dougrainer

Carrolton, Texas

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Posted: 06/12/23 07:35pm

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rvman69 wrote:

Ok so I just hook the two leads from the heating element to an extension cord. Does it matter how the leads are hooked up polarity wise? Do I leave the refrigerator off or does it need to be turned on? I will test the baffle with a stiff wire and see if I can get anything out of it and if it rattles. Then I will blow it out with air compressor. Then I will hook it up to extension cord. I will wait until in the morning so I can be around it for several hours after I hook it up. Is there anything I need to really watch for while it is hooked up. Thanks

Polarity does NOT matter. You do NOT have to be around for the 24 hours. Use a cup of water in the lower section and take the temp from the water. Wiring direct bypasses ALL refer controls. Refer can be off or no 12 volt power to it. Doug

rvman69

philpot

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Posted: 06/13/23 07:14am

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So I guess I should be able to determine fairly quickly if the unit is at least circulating. All of the circulating coils should start warming up. Is this correct? If the circulating coils do not start getting warm after a while then it would mean that either the stuff inside has leaked out or there is a clog in the system. If that is the case there would be no reason to leave it on 24 hours. Is my assumptions correct? I guess then it would be time to order a cooling unit. I hope I dont have to but you have to have a fridge.

dougrainer

Carrolton, Texas

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Posted: 06/13/23 07:46am

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rvman69 wrote:

There is NO danger to running on 120 for 24 hours. This is what I do when I suspect a bad cooling unit. Doug

rvman69

philpot

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Posted: 06/13/23 10:32am

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Can it mess up the heating element if it is not operating and getting to hot? Well I might have my answer already. I moved the burner assembly out of the way so I could get to the pipe the baffle is in good. When I stuck a wire up in there it sounded like I got the baffle to rattle some. I could not get anything out of there. Then I hooked the heating element to extension cord. After it had been plugged in about an hour I ran that wire back up in the baffle pipe. Here is what I got to fall out. If it is bad I don't want to mess up the heating element and have to replace it also. Also it looks messed up in that pipe. See pic. Please let me know your thoughts. Thanks
[image]

JBarca

Radnor, Ohio, USA

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Posted: 06/13/23 11:40am

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Curious about Doug's response to your last pics. Here are my thoughts.

Stop poking at the baffle; you have very little rust in the burner tube, and poking at it can damage or, worse, unhook the baffle from the draw rod. There does not look like any evidence of mud daubers' nests.

The yellow in the burner tube and the glob under it doesn't look good. As you heat the boiler tube with the electric element, the metal expands, and any thin crack in a weld or fatigued joint can start to open, allowing the coolant to start to leak. You may be at the start of the cooling unit failure.

Do you smell any ammonia type of scent when the unit is heating?

Doug has seen more of these failures than I have, and he has the 24-hour full-on electric element test he can report better on than I can.

These pics are of an actual 2004 RM2652 undergoing restoration for water damage, and I service the appliances. They may help you understand what is going on behind the burner insulation. This fridge is a working one, not a failed one.

I did tests to see what the boiler area and the cooling coil temps were at to see what normal is supposed to be.

This is the raw cooling coil out in the open.
[image]

Here is the operation test. The fridge is running under its control system, and I recorded readings at the l location until the unit cycled off the electric element.
[image]

Here is location 1, the steel sleeve the electric element is in.
[image]

Here is the first set of data.
[image]

The second test with more data. I had a cup of water in the freezer and a gallon jug in the fridge as a load for the refrigerator to work on. The remote thermometer is inside the fridge
compartment
[image]

Hope this helps

John

John & Cindy

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rvman69

philpot

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Posted: 06/13/23 01:23pm

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John, Thanks for the photos and information. Well I have had it plugged in for 6 hours. All of the lower pipes I can reach 6 thru 12 on your diagram are still cold to the touch. So there is no movement in the cooling unit is this correct? The flue is so hot all I can do is tap it with my finger with out get burned or blistered. I am pretty sure it is not working at all. I got a feeling I am going to be ordering a cooling unit. I know it takes a long time for it to start cooling down inside fridge and freezer but it should start circulating in 6 hours correct? Just as a note after 6 hours the temp in the freezer and fridge did not drop at all. Thanks

enblethen

Moses Lake, WA

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Posted: 06/13/23 01:38pm

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Looks like you had a fire in the tube. Clump of material could be ammonium fire residue.

Bud
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rvman69

philpot

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Posted: 06/13/23 01:52pm

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Well I had the camper plugged in out in my shop since last November after last camping with the fridge on. The propane was on also. So I wonder if the unit had leaked out some. Then when the storm took out our electricity the burner kicked on and caught the tube inside on fire. Wonder if that could have burnt some of that stuff up maybe clogging that tube up some. Then when electricity came back on it got to hot and thermal fuse popped out. Just an idea. Thanks