My fridge worked perfectly on propane until I hit a horrible bump while bringing her home from Idaho.
It works perfectly on 110v. Very cold and I can make ice in the freezer.
I’ve done all of the troubleshooting I can. The trailer is level front to back and side to side. The propane burner lights and stays lit (it does blow out when I’m driving regardless of speed). The flue gets hot and the back and forth tubes on the back of the fridge get warm but not hot. The inside temperature of the fridge does budge—the metal baffles are hot, freezer is hot, and thermometer does not budge. I left it on for 48 hours without success—it indicated the propane was burning.
I removed the covers below the chimney pipe as shown in several videos but couldn’t find the burner. However—it’s hot.
Did I disconnect something when I hit the bump?
Any thoughts? It’s an old Dometic fridge—not original but old. I appreciate any suggestions. Again—I’ve watched the videos and followed their instructions for troubleshooting without luck.
A bit curious and confused. The "cooling system" doesn't know if its electricty or propane that is applying the heat to the soup inside it to make cold.
Ideas.
Something like a chunk of debris got knocked loose and is not allowing the heat from the flame to go up the flue as it should.
Flame is not at full power. Its not a big flame on a good day but a small flame might be something to check.
Are you able or interested in diving in a bit deeper?
My first thought is along the lines of what GCinSC2 said... maybe something was shaken loose (a baffle, a chunk of rust, etc.) in the flue and it's blocking the heat from the flame from fully reaching the "generator" vessel containing the working fluid. So, the flue might even be hotter than normal, but dissipating too much to the atmosphere and the structure rather than where it's supposed to be concentrated.
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The first photo is of the back of the fridge. The silver cylinder pipe in the upper right gets very hot. The rope-shaped things from the middle left going up get warm but not hot,
The second is of behind the removable plate (with white elec diagram on lower right of fridge; where the burner is in the fix-it videos but not on my stove. It has two wires back there).
Third is higher up on the chimney (I think that’s what the vertical round thing in the middle is is—it gets hot). For orientation, this photo has the bigger part of the round tube things you see in picture 1–the horizontal tube that goes behind the plate right at the electrical diagram sticker—taking up the entire left lower half (it’s out of proportion due to the phone camera). The wood is part of the cabinet frame.
Fourth picture is looking straight up from the trailer fridge opening. I think those silver baffle things in the middle upper left are what go into the fridge to exchange heat, right? They look like what’s inside the fridge that gets cold.
Sorry about the non technical terms but everything is a thingamabobby and a doohickey to me.
Pic 1 remove the sheet metal square panel. It’s just a panel to keep air from blowing flame out.
Pic 2 see the screw on top of the small wrap around shield, remove it and keep it with the wrap around shield. Pretty sure it’s different from other sheet metal screws.
To remove the wrap around might require wiggling and pulling carefully to extract this shield.
If anything seems to be resisting it might be the flue resting on it so just push flue up a bit wiggle and pull. At least that’s what I have to do.
Now just look things over. Should see the burner, and spark igniter a bit model specific.
If you see crud and debris remove it even shake flue slightly to shake debris out.
Take any pics of questionable stuff. It’s ok to test run w/o shields but must be replaced for use.
I’ll see if I have a pic of flame on mine and post tomorrow am if you like.
The burner is right there inside the little box in pic-2. Follow the gas line, it is on the end, usually a long rectangular shape maybe 1.5-2". The two wires are your flame sensor wire and your igniter wire, they both attach to hard wire looking things that are in the actual flame.
The burner is right there inside the little box in pic-2. Follow the gas line, it is on the end, usually a long rectangular shape maybe 1.5-2". The two wires are your flame sensor wire and your igniter wire, they both attach to hard wire looking things that are in the actual flame.
edit: I'm a slow typer and Gary beat me to it.
Thanks! I’ll open it up again tomorrow. I’ll keep you in the loop.
Pic 1 remove the sheet metal square panel. It’s just a panel to keep air from blowing flame out.
Pic 2 see the screw on top of the small wrap around shield, remove it and keep it with the wrap around shield. Pretty sure it’s different from other sheet metal screws.
To remove the wrap around might require wiggling and pulling carefully to extract this shield.
If anything seems to be resisting it might be the flue resting on it so just push flue up a bit wiggle and pull. At least that’s what I have to do.
Now just look things over. Should see the burner, and spark igniter a bit model specific.
If you see crud and debris remove it even shake flue slightly to shake debris out.
Take any pics of questionable stuff. It’s ok to test run w/o shields but must be replaced for use.
I’ll see if I have a pic of flame on mine and post tomorrow am if you like.
Gary
Thanks Gary—yes please post pictures. I’ve taken the shield off but wasn’t sure what else to take off. Is the silver cylinder a shield and not the actual chimney?
I’ll take some more stuff off tomorrow and try to get the cylinder off too. . I’d definitely appreciate pictures of yours. I’d love to be able to fix this by myself.
Having your fridge model number may also help, my comments are based on my fridge model, but close for discussion purposes.
This is just a bit fuzzy I clipped it from a short video of my burner running. You can see the burner, igniter and thermocouple glowing red at the tip over the flame.
And here is a general Dometic service manual. See page 20 in particular regarding the baffle and flue info.
If you do not see any debris run the unit and look at the flame. Crud on or in the burner slots needs cleaned out. The gas orifice is VERY small. Any particle in the orifice needs to be cleaned out. Mine uses a 10mm wrench I think to remove the small brass orifice. CAUTION see service manual for cleaning procedure. No picks, metal or high pressure air to clean it.
What a job! It really didn’t want to come off—it has a bent lip securing it in the back and I was afraid I was breaking it! But I got it off and found the flame thrower and thermocoupler. I didn’t see any crud but blew gently on it and started the fridge. The thermocouple is glowing. Flame is blue and pretty steady. I felt around and found the hanging twisted baffle and wiggled it. I’m waiting for results now.
Model is Dometic RM 2333
Pic 1 is just after I started it. (1 & 2 are upside down)
Pic 2 is the thermocouple glowing like yours. How do the flame and thermocouple look to you? Normal? Not?
I can’t delete the last pic. I thought it was the model number but it’s not.
I’ll let it run for a bit
The flame looks nominal. If you don’t get adequate cooling, I suspect that the flue is full of crud.
On my previous trailer, the reefer, a Dometic RM2800, had the same problem. To fix it, I had to pull the reefer into the kitchen and clean the flue. I used a 12 gauge shotgun cleaning kit with threaded rods… Be very careful removing and reinstalling the baffle at the top of the flue.
Be sure to cover everything at the bottom of the flue before brushing as you will be surprised at how much stuff comes out (On mine it was mostly rust flakes and soot with a dusting of spider). Might want to have a vacuum standing by…
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Debris and crud in the chimney as several of us have mentioned.
Propane pressure. this requires a special test rig and manometer to correctly test propane system pressure. 11" Water Column is spec.
Orifice debris.
I have to preface this one as your model fridge and mine are not the same. I have video of my flame and the inner blue flame cones on mine are at least double the height of yours. Take a second look at the difference but mine is not the same model as yours keep that in mind.
The orifice is really quite easy to R&R just be careful.
And look at the pics again, see how red the igniter and flame sense (Thermocouple) are compared to yours?
Yes, yours seems redder. Propane tanks are full. I just got them, and have a gauge which shows full. As I mentioned, it worked perfectly before the bump. Previous owner’s elderly parents used the trailer and he kept everything in very good condition. I used it for a couple of days on propane before the bump.
I’m letting it cool now so I can reach up to see if I can feel the twisted baffle shown in the diagram in the pdf you sent. I found the service manual for mine and it wasn’t as detailed.
How do I get the flue out to clean it and to check the baffle, please?
The flue baffle hangs on a wire from the top, might be hard to impossible to remove with fridge in place. It usually hangs right under the top flue fitting as it exits the boiler tube enclosure.
If you can reach the access door on the boiler/flue enclosure and open it up, pull back the insulation and hit the boiler tube with an IR gun it should be over 300F. The boiler tube and the flue are right next to each other so make sure to hit the boiler tube with the IR gun. My boiler tube runs around 315F when it is heating.
Hello Curiosity
In your fourth photo, I don't see the thermistor. It's a tiny disc switch that is turned on and off by the heat coming from the cooling fins that are shown in that photo. It may well be a clip on arrangement on the end of a single conductor. It may well be there, just not within view of that picture. I'm unsure what its being detached would do in this scenario but it would be worth making sure it is in place. Those cooling fins are how the fridge circuit sheds heat from the coolant system.
I wish you much luck in your searches.
Ladies and Gentlemen, I have been following this thread and trying ideas. But I have determined my 15 year old fridge needs to be replaced. I want a 3 way (12V, 110, propane) and it seems the path of least resistance is to buy the same model dometic RM2662. My first question is if it is reasonable for a non handy dude to order one and try to replace and if I want to take no chance on my lack of skills, do I need to take it to an airstream dealer or can any reputable RV repair shop order in and install a new fridge.
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