Our 179 has a Dometic RM8501 refrigerator with a new problem while operating on gas mode.

It works fine on electric and battery power.  It has worked fine on gas until now.

It will ignite and continue burning.

However, it "pops" and "burps", the flame turns off and immediately comes back on.  This happens several times per minute and each stoppage lasts for a second or two.  The flame always comes back on-sometimes with the igniter and sometimes it doesn't stay off long enough for the igniter to work, but still the flame comes back(I guess that the burner is hot enough to re-ignite the gas)

It seemed to be bad propane, so  I changed tanks. Same issue. I turned the tank off, purged the propane lines ans still have the same issue.

I broke it down and cleaned the burner, the igniter, the flame sensor and the orifice as well as blowing out the line from the gas valve to the burner. We still have the same issues. I redid all of the cleaning process, including soaking the orifice in alcohol for 45 minutes-same issue.

I have pulled/pushed/twisted all wiring coming into or out of the electrical boxes on the rear of the refrigerator and no change.

It doesn't seem to be a physical/mechanical problem.

Now, I'm thinking it must be either (1) the gas valve is stopping the gas flow for an instant and then returning to normal OR (2) there is an electronic issue in one of the circuit boards that is causing the issue.

I have called Dometic technical services and they are NO help. They say take it to a qualified service tech(which I may ultimately have to do)

I would appreciate any thoughts or suggestions.

thanks

Travel often and safe

Vann

I should add that I tested the stove burners and the heater-all worked fine.  The tank is 3/4 full and the pressure seems normal for stove burners.

so, I am fairly confident it is NOT a propane problem.

Vann

That doesn't sound like normal operation even for a dometic.  The pops and burps happens several times a minute right?  The pops and burps are a few seconds long right? And these continue for the entire time the fridge is on the gas mode right?  How long have you run the fridge playing that tune?  Have you run the fridge lone enough to tell if it does an adequate job at cooling the fridge while harmonizing?  Does the flame seem to be bright blue and is it of a good size?  The only thing that comes to my mind is that there is a bimetal sensor that should be in the flame that has to check the presents of a flame or it will shut down the gas flow.  There maybe an intermittent problem with that sensor.  Hope this helps you.

Hello Jay

Thanks for the quick response-

yes--the spits/pops/burps do last about 1 second and continue seemingly forever.  I have left it on for 15-20 minutes and it is the same.

I have not tried to actually cool the fridge since this started(except electric, which worked fine).

the flame is strong-deep blue and you can actually hear it.

I know the flame sensor you ask about-it glows orange and i also cleaned it with steel wool and alcohol.

Do you know how to test the sensor or where to find a replacement?

Thanks for your help

Vann

Reading your fridge's symptoms and your remedies the only thing that came to mind could be a faulty flame sensor.  I don't know how to verify its workability or where you can find a replacement. I found this link on youtube which seems to be relevant to your fridge's symptoms  https://www.youtube.com/watch?v=biybQ7qI4Fo6/2-6/9 - https://www.youtube.com/watch?v=biybQ7qI4Fo6/2-6/9  Hope this helps.

thanks for the video. Unfortunately,the video issue is not my problem. His is an igniter that will not stop.

My problem seems to either the flame sensor or something electronic that controls the gas valve.

It seems like the gas is turned off for a half second, the flame burps/spits and goes out. Immediately, the flame returns(good, bright blue) sometimes spontaneously and sometimes one click of the igniter. I know the igniter works.

I cannot find a parts diagram for the RM8501 to find a part number for the flame sensor.  I will try again to talk to Dometic tomorrow.

Thanks for your help

Vann

thanks everyone for your ideas and suggestions.

We are leaving Monday for a short 4 day  trip, so I have put off any further work on the fridge for now.  We will be staying in a US Park Service campground with power, so I will use 120v  for the fridge.

a potentially new development has come up.

We talked to a mobile repair service and a dealer who we have used before.  It sounds like it could be a control board issue.  If so, we will spend several hundred diagnosing and repairing plus the parts cost. could be $5-600 or more-and it's still a 2015 model approaching 9 years old.Plus, we have had a lot of trouble with this unit over the full time that we have owned it(2017)

So we started thinking about removing the microwave and putting in a new , larger(6 cu ft) refrigerator.  Both Dometic and Norcold make a unit that we can make fit into the combined fridge/microwave cabinet. We never use the m/w as we normally boondock anyway. We can pull out the old fridge and adapt the cabinet and let a dealer purchase and install a new model.

So.........

anybody got experience doing this? or with Norcold?

Again, thanks

Vann

You are making a wise decision.  Our dometic lasted 9.5 years, and were told the lifespan on these are 10 years, so unfortunately it seems like yours is near the end of life as well.  It was replaced with the same model.

Question do either of the units you are looking at work on propane as well as shore power?  It seems like a lot of manufacturers are getting away from propane - which is not good - that is all we use - as we normally camp where no electric is available.

thanks for the encouragement JATO.

Yes, anything we put in will definitely operate on propane.  some of the newer models are 3 way and some just 2 way(AC/propane)

We almost always boondock, so propane is a necessity.

Vann

Excellent points. The fridge is the only device that uses a very low flow flame, and is then more likely to be affected by little obstructions such as the gunk in the gas line.

Not a difficult fix. Let me know if you have any questions.

Great info--THANKS!!!

I have talked to Dometic many, many times over this issue. The bottom line is that the part GEBaldwin1 has shown has been superseeded by Dometic.   The parts list for the RM8501 shows a completely different burner unit.  I questioned Dometic and here is the response

"Hi there Vann, thank you for sending in the pictures and information on your unit. I have reviewed everything and have found that your original part has been superseded. The part listed is correct and current however, it may look a tad different but will work and connect properly with your unit. I have provided some pictures below to show the part has been superseded and what the part looks like now.  The correct CURRENT part number is 2412802825.

 

sorry the pictures from Dometic didn't show. I will try to get them to work

Vann

Here is the dometic email with pictures-sorry for all of the double and empty posts

"Hi there Vann, thank you for sending in the pictures and information on your unit. I have reviewed everything and have found that your original part has been superseded. The part listed is correct and current however, it may look a tad different but will work and connect properly with your unit. I have provided some pictures below to show the part has been superseded and what the part looks like now.  The correct CURRENT part number is 2412802825.

 

here are the correct images for my earlier post-I cannot put them in the email from Dometic, but they are in the same order as shown above in the email

https://postimg.cc/Sj7hM0Dh">

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https://postimg.cc/2V0N04s9">

Changing over to a larger fridge, I know there have been some that have done it already, but do you think that the weight will be an issue because of the floor plan of your 179??  I haven't heard any weight concerns from the people that have done that modification.  ?? Good information from Dometic, thanks.

PS the reason my line was clean is, that I bleed my lines after every trip.

JR-regarding the weight question

I did research this prior to making the decision.  The Dometic RM8501 has a listed weight of 62#, and the M/w is 49#. given that we will also be removing several(???)pound of excess wood, the total removed should be around 115-120#.

The new Norcold N4150 has a listed weight of 85# plus whatever wood we have to install. 

so, i think we will still lose about 30 pounds overall with the changeout.

We picked up the new refrig yesterday and we will start tearing out and redoing the cabinet next week.

I will take pictures and post the results later.

Thanks again for all  of the advice and input from fellow podders.

We will probably sell the refrig for parts if anyone needs anything

Travel often and safe

Vann