Dometic 3-way fridge not cooling on gas

[CalgaryEscape]

Hi: I have a small Dometic fridge - model RM 4223. It cools well on 120 and 12V, but barely cools on gas. Tried cleaning the gas tip with a pipe cleaner and alcohol, but that didn't really do the trick. Flame doesn't get bigger. Any suggestions? Should I suspect the Thermister? Anything else? (BTW, took it into a local shop, and the RV repairman declared it dead and claimed it wouldn't cool at all . . . basically, either a liar or incompetent. Figured I'd do better tackling it myself.) Open to any and all suggestions.

[Raz]

If the flame stays on, the thermalcouple is fine. When my fridge fails to cool, it's time for a good cleaning. Look in the document center in the left hand column and find the manual for your fridge. I'm guessing it will be there. There should be instructions. When I clean mine it has to be removed to gain acess to the chimney. If cleaning doesn't improve performance it might be time to replace the regulator but try cleaning first.

[gordon2]

First.. see this site which says in part,

UNDER NO CIRCUMSTANCES should you insert any object - drill bits, broaches, paper clips, needles, etc. - into the orifice opening. Because these orifices are made primarily of brass or aluminum, (some older refrigerators had orifices made of rubies!) they are fairly soft, and the opening could easily be distorted.

Next, when is the last time you had the propane system checked? Because the fridge flame is so small it is sensitive to out-of-spec propane systems.
There are an almost endless number of resources on the internet on how to troubleshoot an absorption fridge. I would look some of them over, starting with the one I linked to above.

Originally Posted by CalgaryEscape

... basically, either a liar or incompetent. ..

He could be both. Kinda sounds like he might be.

[CalgaryEscape]

These are super-helpful ideas, folks. I have the fridge out already, so I'll start with a thorough cleaning. But the tip about checking the propane pressure makes a lot of sense to me. I suspect that may make the difference.

Shoulda tackled it myself in the first place.

[ZachO]

I know if I had run a pipe cleaner through my burner jet, there's a nearly 100% chance it would need to be replaced.

Is this a new-to-you trailer? Or do you know when it last worked on gas?

[CalgaryEscape]

I'm going to have to get that jet out and visually inspect it. I think I was pretty careful when I tried to clean it, but I'm not 100 % confident that I haven't caused some harm.

I bought the trailer late last year, and I don't think the fridge was working very well on gas then. The previous owner had put a small battery-operated fan inside to circulate the air, which was probably reasonably close to useless. I believe the problem existed when I bought it.

The chimney is clean . . . too clean. Suggests to me that the flame was never really hot enough.

[gordon2]

Originally Posted by CalgaryEscape

...The previous owner had put a small battery-operated fan inside to circulate the air, which was probably reasonably close to useless.....

I actually find it works pretty well (as long as the fridge is working properly). Stock the fridge so that there is room for the air to circulate over the cooling surface.. the fan makes the internal temperature more consistent and helps to prevent warm areas. But of course it wont help presently in your case when using propane.

[thrifty bill]

Originally Posted by CalgaryEscape

RV repairman declared it dead and claimed it wouldn't cool at all . . . basically, either a liar or incompetent.

I vote incompetent. There are a lot more incompetent people out there than liars. Some people get into the service business despite lacking diagnostic skills. I call them "parts swappers". Finding someone who is really good is challenging.

Addressing the original refrigerator on my old Trillium is "on the list." Right now, I am wrapped up doing a whole house remodel/rebuild. That will take me the rest of this year.....

[ZachO]

Yeah the interior fans work great, but they can't make up for a non-functioning cooling unit. They work well assuming the fridge itself is working well.

There are all sorts of things to check here. I have no idea whether Aliners have a reputation for poor fridge installs, but often trailer manufacturers don't do a good job of following the fridge instructions for install.

But assuming they did a good job, things to check, off the top of my head:

propane pressure at the fridge (read the manual. there are narrow specs for what it needs to be)
flame color (if it's not completely blue, you need to clean things)

Then it quickly gets into how well the chimney effect is happening, which has to do with the install. If you need to help airflow, there are all kinds of threads on this forum and others on how to baffle, add fans, insulate, and modify the box built around your fridge.

[Nicolas]

Just tuned into this discussion and:

I agree that the propane system should be checked out. Everything from mud wasps to spiders, etc can do a number on propane feed or as in my case a mysterious failure in a hose.

I just stated in a post yesterday on welding but the same applies here, search out a good local person for each job you do. And I agree with the fact that this is a tough thing to do but ask around in your area. I also tend to shy away from places that don’t have a regular business, are too well-to-do and have well-to-do customers [not always a true tell but ...] and don’t offer to help try to solve your problem.

All the best in solving the propane issue. It’s an important part of the experience especially when you are away from civilization and you want to conserve battery power.

[Joe Romas]

The refrigerator jet at least on my Dometic, has a red jewel with a tiny hole in it, no way would a pipe cleaner even fit and as noted already NOTHING is to be stuck into the jet. To clean the nozzle your supposed to use "wood alcohol" but I don't think you'll find such a alcohol in the US. I use carburetor cleaner in a spray can and have not had a problen in the 14 years we've had our 1999 Casita SD. The manual says should be cleaned yearly. Regulators do go bad too and the fact that your other propane appliances work fine does not rule out the regulator. That's because the stove, water heater and furnace all have their own regulator that further lowers the pressure but the refrigerator does not and totally relies on proper pressure from the main regulator.

[Raz]

Originally Posted by CalgaryEscape

I'm going to have to get that jet out and visually inspect it. I think I was pretty careful when I tried to clean it, but I'm not 100 % confident that I haven't caused some harm.

I bought the trailer late last year, and I don't think the fridge was working very well on gas then. The previous owner had put a small battery-operated fan inside to circulate the air, which was probably reasonably close to useless. I believe the problem existed when I bought it.

The chimney is clean . . . too clean. Suggests to me that the flame was never really hot enough.

When I clean my fridge I check the orifice with a microscope and only once did I find anything, a small speck of dirt. I soak it in alcohol anyway. The chimney and diverter (that twisted piece of metal hanging from a wire) some times have carbon build up which I clean with a brush. The part that I suspect causes the poor performance is the grate. Both carbon build up and carbon fallen from the chimney clog it up. That I clean with a brass brush. When done it's hard to see a difference in flame size but the improved performance is evident. Be aware, these fridges are slow to cool. It could take a day.

[ZachO]

The chimney is a really important part to clean. He said his was really clean, so I left that off.

I bought a cheap shotgun cleaning kit, and the wire brush it came with is a perfect size for my fridge chimney, which definitely has needed cleaning a couple times in the last few years.

My burner jet ruby had a tiny crack in it last summer, which I also noticed with a magnifying glass. Didn't really notice if it heated better after replacing it.

[ThomasBalmer]

My fridge didn't cool well on gas, and I tried reversing the numbers. I was turning it to 7, thinking that was coldest, but it cooled more on 1 (and I haven't used it since the fall, so I may have it backwards) try using the other end of the scale. By the way, it uses a tiny flame, not much more than a pilot light.

[Glenn Baglo]

Originally Posted by ThomasBalmer

My fridge didn't cool well on gas

What brand? What model fridge?

[thrifty bill]

Originally Posted by Joe Romas

The refrigerator jet at least on my Dometic, has a red jewel with a tiny hole in it, no way would a pipe cleaner even fit and as noted already NOTHING is to be stuck into the jet. To clean the nozzle your supposed to use "wood alcohol" but I don't think you'll find such a alcohol in the US.

You can buy "wood alcohol" in several places in the USA including Amazon. Chemical name is methanol. Its the alcohol you can't drink.

Whether it should be used at home is another story.

From a MSDS for Methanol:

"Toxic in contact with skin. Toxic if swallowed. Toxic if inhaled."

We used it in the industry I worked in, there are many things more toxic. At the same time, bringing chemicals into the home adds risk and typically the lack of PPE, training, and proper storage can make it a really bad idea. Also highly flammable.


https://www.amazon.com/Duda-Diesel-B...6-f96e7b0f409c

[john hackert]

I had a similar situation to yours and I found cleaning the burner by soaking it in lighter fluid made all the difference. There may be a filter on the gas regulator at the tank that is clogged too I had to start it with a match while my wife held the gas starter down in the trailer. In mine you have to push the control down until it starts in the trailer. I presume you are getting a spark from your piezo starter but they wear out but a match always works . Its certainly worth fixing as the cooling from gas is a lot better than you will ever get from 12 volts. My unit is 30 years old and it will freeze ice and fish .

[patrick crawford]

after 10 years or so of trying to make dometic's "box of promises" behave like a fridge i finally pulled it out and tossed it. replaced it with a 12v/120vac unit with a danfoss compressor. it's still a small fridge (but it does have a freezer) and i carry a solar powered cooler in the bed of the truck for "overflow". finally i get to go camping and have cold food.

p@

[Jim Park]

I was having a similar problem and the RV dealer replaced the regulator on the front of the Boler and I've had no problems since.

[greenghost45]

Originally Posted by CalgaryEscape

Hi: I have a small Dometic fridge - model RM 4223. It cools well on 120 and 12V, but barely cools on gas. Tried cleaning the gas tip with a pipe cleaner and alcohol, but that didn't really do the trick. Flame doesn't get bigger. Any suggestions? Should I suspect the Thermister? Anything else? (BTW, took it into a local shop, and the RV repairman declared it dead and claimed it wouldn't cool at all . . . basically, either a liar or incompetent. Figured I'd do better tackling it myself.) Open to any and all suggestions.

NEVER clean propane or gas orifices with wires, pipe cleaners etc. You should use compressed air, preferably high pressure of 100 psi. If you don't have access to an air compressor, you could try one of the cans of compressed air used for cleaning computers, but that may not not have enough pressure. With suitable compressed air, you don't need alcohol, lighter fluid or anything else to clean the gas orifices in your fridge.