Frig will not cool on gas - works okay on AC electric

[TankerIP]

My RM2452 Dometic Americana has stopped keeping cold when using gas. It seems to work fine in AC power, I am in the process of trying to figure out what the problem might be and how to fix it.

I used compressed air hose to blow out around the combustion area. I switched gas bottles. i was getting enough gas to burn in the stove range and the furnace. The frig burner flame appeared okay, i.e, blue and about the right height.

I think I need to check the flue, but there is not enough room in the compartment to pull out the baffle wire for inspection.

I suppose I need to pull the frig out of its compartment, but I don't really know how to do it. Any help or advice would be greatly appreciated. I expect I will shut the gas off and uncouple the gas supply to the frig burner.

How heavy is the refrigerator? If I remove the two bolts at the bottom in the outside compartment, is that all I need to slide the frig out into the interior of the trailer? Some sites talk about getting something like a long bottle brush to clean the flue. Is this available at Home Depot?

Anything else that I am missing?

[IanPoulin]

Understanding it could be a number of things, I had this issue last summer on my dometic fridge. The principle check dometic had me undertake was to check the thermostat (thermistor check) by placing it into a glass of ice water for 10-15 minutes; then taking a resistance reading. Once it was shown the thermistor was working in spec range, it was deduced to be the lower circuit board. I forget now, but believe it to be about a $200 part, and one for which an electronics n00b such as myself was able to replace on my own, with success, that day.

Dometic has service manuals online in PDF format, which walk you through each and every step to check and validate each step, if you are so handily inclined.

good luck!

[HowieE]

Before you do anything else check to see if the burner is lighting.
You can remove the shroud at the base of the chimney and see the burner.

While looking at the burner have someone try to light the frig. If it does not light at all i would check the fuse on the control board. If it lights but goes out I would consider the thermocouple and take a small wrench and loosen it at the gas valve and retighten to make sure there is a good contact. You may have to replace the thermocouple.

If it had just been working you should be able to solve the problem without removing the unit.

[TankerIP]

I have not had any trouble with the burner. It lights and continues to burn. The canister that surrounds the flue remains hot (but maybe not hot enough) for days without allowing the the frig to cool enough (like it does on AC)

I removed the shroud around the burner and it appears to have a good flame.

[HowieE]

Well if it works on AC and has a flame when on gas that proves the controls and the sealed cooling system.

Possible problems may be a clogged chimney or reduced flame. Is the flame blue or yellow? Should be blue. Is the surface of the burner show any signs of dirt, rust flakes, on the surface reducing gas flow.

There is no easy way to check the chimney with out removing the frig or removing the vent cap on the roof.

[TankerIP]

So Ian,....Did you contact Dometic directly? Will they help you diagnose problems even if the unit is out of warranty?

[TG Twinkie]

Sounds like you are not getting good heat transfer. Something must be blocking the chimney.

[TankerIP]

Originally Posted by TG Twinkie

Sounds like you are not getting good heat transfer. Something must be blocking the chimney.

That's what I suspect. And so back to my question, how to remove the refrigerator in order to inspect the flue. It looks like it will have to come out completely in order for me to have access to inspect, and clean the flue.

[CRH]

Mine did not cool good on gas when I got it. The flame looked good. However, I was not getting enough gas. I adjusted the propane regular and solved the problem. Fortunately, mine has a gauge in the gas line right where it looks to the fridge.

[HowieE]

Yes, before removing the frig test the gas line for pressure. It should be 11 in. If it is low your regulator on the tank may have failed.

[IanPoulin]

Originally Posted by TankerIP

So Ian,....Did you contact Dometic directly? Will they help you diagnose problems even if the unit is out of warranty?

TankerIP --

I phoned them directly and although I was out of warrantee, their service help desk was willing to provide the information I needed to check the thermistor and ultimately replace the computer board.

[TankerIP]

I have decided to try one of those "mobile RV repair" businesses. It seems I don't really know what I am doing, or don't understand how the frig works. I could have a pressure problem, or a thermostat/thermocouple problem.

I can't find a manometer, and I feel like I need to check the gas pressure. Home Depot no longer carries manometers...Amazon will deliver one next week...I need it now.

I tried to check the voltage on the thermocouple while the flame was on. It showed 0.0 mV (assuming I was checking correctly). If I wanted to replace the thermocouple I would have to pull the frig out since switches, thermostats, and connections go to the top of the frig -- a location that's inside the cabin.

I hate to give up, these things should be easy. But without diagnostic tools and understanding how this frig works, I might get in trouble.

[boblind]

Pull the fuel selector knob out and make sure the stem is rotating when you turn the knob. If it isn't try using a needle nose plier to make sure it's on gas.

[SeeMore]

TankerIP - I hope this helps answer your direct question.

The refrigerator is mounted with 6 screws usually. The two in the rear you see from the exterior hatch and four inside. The four inside are two at the bottom and two at the top. Some pieces of the plastic flashing need to be popped off to access them. On most models, the access is achieved by removing the covers at the hinges locations. Simply pry up the edge carefully; a thin insert works sufficiently. On others, both the hinge cover and cross piece need the removed.

Once everything is disconnected from the electrical and gas lines, the refrigerator slides into the interior space. I built a temporary table, four 2x4 legs and a rectangular surface (24"x30") of 3/8 plywood screwed vertically into the legs, at the height of the bottom of the refrigerator and placed it in the hallway. Once this is done, it is a one man job to push the refrigerator inside a few inches from outside, then go inside and pull it the rest of the way onto the 'table.'

The baffle is simply removed from the top of the flue: it is similar to a straight coat hanger wire with a 3" twisted piece of metal connected at the end. Clean it and the flue. I use a stiff wire with a small piece of scotch pad affixed with green flower wire to resemble a bowtie. The 'bowtie' need only be as wide as the flue because you aren't going to scrub the tube, just lightly brush the surface. Run it down the flue and up again. The problem, if flue related, is most likely a cobweb or other small obstruction like a flake of corrosion that causes the rising heat of the flame to flow improperly.

[AtomicNo13]

I second the regulator issue. I discovered last summer that a newly replaced regulator was defective and providing far less gas than what it should have. After replacement, my fridge cools like never before!
I can literally freeze Popsicles in the fridge if I desire!

[Foiled Again]

Yo! Everyone - this is a 2002 22footer. Does your model have the little refrigerator that fits under the kitchen counter? If so the "chimney" if I remember correctly is a vent on the side of the Airstream - and two words

MUD DAUBERS

They will clog up anything in a New York Minute.

Get a big can of insect fogger, take the plastic vent cover off, grab the fogger and deploy it near the nest and run like crazy... Oops that's summer time version. They should all be dormant now, so just get your shop vac and suck out the daubers and nest and you could be good to go. If you don't see a nest the mobile guy would be my next choice.

Good luck and may the charge be low. Paula

[TankerIP]

I had a mobile RV repair tech come by. He observed the flame I had. He removed the gas orifice, blew it out with compressed air. Pulled the bafffle out of the chimeny and said that was all clean. He measured the pressure at the frig and found it to be 11 inches. Then he adjusted the regulator up to 13 or 14 inches. This made a great difference. The frig started to cool just fine.

I paid $140 for the service.

But on my trip I notice one thing I never had a problem with: the gas will not stay lit while I go down the road. I used to be able to travel long distances and the frig would continue to operate. Not the case now. I guess the flame is getting blown out at highway speeds. Not sure if there is something to do about that.



I think I will order a manometer on the internet. Just to have around and to be able to periodically monitor the system pressure myself.

[idroba]

Your service guy has raised the pressure too high, if he has set it to 13 to 14 inches of water. That may push more propane through a restricted opening, and make the refrigerator work, but it can also cause flame lifting from the burner tube, causing it to blow out when traveling far more easily. In addition, you may have other issues with the water heater and the stove.

The pressure needs to be set at 10 to 11 inches of water, and the real problem located, which I suspect is a partly clogged burner, or orifice. Just blowing the orifice out with compressed air probably will not clear it if it is clogged. It may need a soak in alcohol, or even replacement.