Fridge: Okay on AC power, no-go on LP

[samclem]

I'm about to start troubleshooting the fridge on our Casita (a Dometic "Americana" RM 2453, AC and propane only). It works fine when hooked up to shore power, but doesn't get cold at all on propane. It would light with the built-in ignitor, but wouldn't stay lit after releasing the "start button" valve unless I "fooled" the thermocouple by adding heat using a butane lighter for 30 seconds. Then it stays lit, but won't cool.

With the LP going, there seems to be quite a bit of heat coming out of the top "flue" vent, more than when it is on AC. But, still the fridge isn't cool at all.

My next steps:
- Assume maybe the gas isn't putting out enough heat after all. I'll rig up a manometer and check my pressure and also clean the orifice fort he fridge. The LP water heater seems to heat fine and the stove burner flames look okay, but I suppose the pressure might still be low.

Is there a common problem that I'm overlooking, or something else I should try first? I haven't taken apart the portion of the fridge under the shroud where the AC and LP apply heat to the refrigerant fluid.

Thanks.

Mark.

[rdickens]

Similar ..... ?

Dometic RM2410.2RX

http://www.fiberglassrv.com/forums/s...ad.php?t=79369

Ray

[Raz]

On my 2193 when the gas lights but the fridge doesn't get cold it's time to clean the burner.

[mszabo]

Take the gas tube apart and clean everthing. You may have a spider nest in the orfice and it's not letting the gas through. Remember it's low pressure.

[stevebaz]

When this happens to me I have to get into the burner and clean up the inside of the burner and the orfice that feeds the burner. There are some little tiny ass spiders that spin the finest webs in there and while the burner may light there just isn't the proper flame. If the regulator is old dont waste time fooling with it just replace it. When I got my old trailer there was tar like residue in the coper tube that needed to be flushed out. Any of that stuff goes down the line the fridge will have issues.

[Gerry]

After all said it sounds that your fridge works so the refrigerant is still entact and if there was good heat in the chimney the burner is working also.
Is there a seperate Thermostate for AC and Propane on back of fridge?

[patrick crawford]

the fridge is the only gas appliance that does not have a built in propane regulator...it relies on the pressure provided by the regulator at the tanks.

the orifice in the gas line at the burner tube is tiny and can become blocked partially or totally.

i would expect that perhaps one of these may be the source of your issues.

the first is remedied with a new regulator (you can test with a nanometer if you have one and know how to use it).

the other requires cleaning the orifice. consult your owners manual for info on how to accomplish this. do not try to clean that tiny hole with anything except air and alcohol (denatured). the synthetic ruby is very fragile.

p@

[Joe Romas]

P@.

Thanks for saving me all the typing. (that's my usual reply almost exact to the wording)

Mark
What year is your Casita? Cleaning the jet and fire tube are yearly maintenance items.

Joe

[dmad1]

Not exactly related but 30 yrs. ago I bought a very used Class C shell. It belonged to a clothing salesman and he had removed everything including the refrig. and put in hangers for his merchandise. He had kept the refrig. and gave it to me. Installed it and it lit up just fine. Went into the house for a couple of minutes and when I returned, flames were coming out the vents on the side of the camper. After shutting off the propane and a good watering down, I found a very small split in the copper tubing that I had over looked. Should have let the thing burn to the ground. It was nothing but trouble.

[samclem]

Well, the fridge is cooling on propane now.

I did two things (cleaned out the burner tube and cleaned the orifice), so I can't say which did the trick. No really obvious problems (webs, spiders, tons of gunk, etc). It doesn't appear to be cooling as rapidly as it was on AC power, but the freezer is cold, I'll see if water freezes tonight.

Joe,
It is a 1999 Casita, but I bought it a few months ago, so don't know when the refrigerator maintenance was last done. The trailer is in good shape, though.

Thanks for the assistance and patience.

Mark

[Jann Todd]

Originally Posted by samclem

Well, the fridge is cooling on propane now.

I did two things (cleaned out the burner tube and cleaned the orifice), so I can't say which did the trick. No really obvious problems (webs, spiders, tons of gunk, etc). It doesn't appear to be cooling as rapidly as it was on AC power, but the freezer is cold, I'll see if water freezes tonight.

Joe,
It is a 1999 Casita, but I bought it a few months ago, so don't know when the refrigerator maintenance was last done. The trailer is in good shape, though.

Thanks for the assistance and patience.

Mark

These fridges don't get cold as fast on propane as on electric. We always chill the fridge for several hours before loading in food when leaving on a trip. It helps with the stress of cooling down the fridge. It also saves a lot of propane doing this. You are lucky. We had one that didn't work on propane and had to replace the fridge. The dealer paid for half of the cost so we know it was a bad fridge.

[Raz]

Don't forget the chimney. Build up there can flake off and land on the burner.

[Jennifer Minogue]

We found that the vent cover didn't allow enough heat to escape so if we remove the vent cover it works better. Adding a fan is even more effective. Ours is a retrofit on a Captain trailer, not installed by the manufacturer of the trailer.

[stevebaz]

These fridges have installation instructions and if you follow the instructions they will work much better than just sticking them into a cut out. There are certain clearances that have to be maintained for the air to properly draw through the cooling coils/fins. Make sure the air-box is sealed to the outside vents you don't want to be breathing exhaust inside the trailer.

I pulled the cook-top out of my Scamp and the taped together ducting for the fridge had failed and had to be redone. That alone helped my fridge work much better.

With these fridges every little thing counts.

[samclem]

Originally Posted by stevebaz

With these fridges every little thing counts.

Originally Posted by Jennifer Minogue

Adding a fan is even more effective.

I'll have to work on fine-tuning it. On propane and "max" cooling, the freezer got down only to 30 deg F and the main compartment was at 50 deg F. It was just 78 deg outside and the fridge was on the shaded side of the trailer, so this probably isn't going to cut it once the weather turns hot.

My next steps (in a couple of weeks):
1) Check the actual gas pressure with a water tube manometer.
2) Check to assure the flue isn't obstructed.

On my Casita, the vent grill over the upper section of the trailer is riveted and caulked in place, so it will involve drilling out of rivets or removal of the fridge from the inside (?) to do a thorough inspection of the flue. But the unit works fine on AC power, and that's the main thing right now.

[Byron Kinnaman]

Many propane appliance problems are solved by cleaning out the cob webs. Spiders cause a lot of problems.

[Joe Romas]

Originally Posted by samclem

On my Casita, the vent grill over the upper section of the trailer is riveted and caulked in place, so it will involve drilling out of rivets or removal of the fridge from the inside (?) to do a thorough inspection of the flue. But the unit works fine on AC power, and that's the main thing right now.

Before I updated to the newer plastic grill on my 1999 Casita I replaced those rivets with #8 x 3/4" SS sheet metal screws!

Once removed you will be surprised how small the opening is compared to the grill
the newer plastic grill is smaller overall but requires opening the hole in the side of the Casita.

Joe

[rdickens]

From the class I took, the most common causes of poor RV fridge cooling are a partially blocked flue/chimney and unlevel operation.

Since it is/was cooling OK(?) on 110v, I was guessing that the unit was
fairly level and that there was acceptable airflow up the flue/chimney.
That seemed to leave insufficient heat from propane combustion as
the source of the cooling problem.

There seem to be quite a few tutorials, related to RV refrigerator
troubleshooting, out on YouTube. This was just the first hit that my
initial search came up with:

https://youtu.be/FCqiVqZx5k4

Good luck!

Ray

[ZachO]

Back last summer when I was going through a bunch of crap with my fridge, I remember looking a lot of tutorials and reading a lot of threads. At most, I saw mention of cleaning the chimney, but no photos, no videos, no instructions. If someone knows of good instructions I'd love to see them. Someone mentioned finding some sort of pipe cleaner or something. But I remember not easily seeing how to remove it.

Do you clean it in place or remove it? What did you use? What has worked for people who have cleaned theirs?

I cleaned the orifice and burner, banged on the chimney to get stuff out, took out the fridge and ran it on AC then flipped it over, put in a baffle etc. That stuff sort of helped but not really. Finally, I installed a fan in the top vent, and that helped. But it still just keeps my fridge in the "safe" zone when the temps get into the high 80s.

[Raz]

To service I remove the fridge and put it on the front bed. There, everything is easy to get to. Cleaning the flue involves removing the baffle (C). On my 2193 there is a screw holding the Tee (A). I don't remember what kind of brush I used, could be an old tooth brush or a small brass brush. As I recall, surrounding the flue tube are the two heating elements and the refrigeration tubing so don't tap on the outside. There are manuals for various refrigerators in the Document Center.