Dometic 3-way maintenance (burner and switch cleaning) how-to

Discussion in 'Refrigerators and Coolers' started by Pozi, Jul 31, 2018.

  1. Pozi

    Pozi Member

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    After making this post is when I finally realized Digger also had a burner assembly how-to. My bad. Didn't mean to step on any toes, Digger. [:D]

    After taking the PUP out a few weeks ago; we had everything up and running on 120V before our departure. I did not test the refrigerator on propane while at home because it worked perfectly the last time we used it. Unfortunately, the refrigerator didn’t work at the camp site; so we had to transfer everything to the cooler.

    As a result, I figured I would create this write-up for doing maintenance on the PUP’s refrigerator. Below is my experience in cleaning the burner and cleaning the 12V/120V switches in a Dometic 3-way. I did not detail removal and reinstallation of the refrigerator.

    This is just my thoughts, but I think what prevents the refrigerator from working properly is that the burner gets lodged full of rust particles from the various pieces of the refrigerator. You’ll see from the photos below that the flue, flue top, baffle, baffle hanger, burner assembly, etc all have surface rust. The rust slowly breaks free, falls onto the burner and prevents a good flame. Keep in mind that the pilot light might work perfectly but unfortunately the flame will not.


    Burner cleaning.

    Keep in mind this is after removing the refrigerator and placing it on a work surface.

    Remove burner assembly located just below the flue. You’ll also need to remove the propane line, ignitor and thermocouple. Ignitor and thermocouple are both held into place by one screw and bracket. Hopefully that removal step is self-explanatory since I didn’t take a photo.
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    You’ll notice the stainless steel orifice located inside. Be sure not to lose it!
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    Using various tools, clean the interior of the burner assembly. There is a lot of gunk that get lodged on the interior. I used a drill bit sized just perfectly to fit inside and carefully drilled the inside just enough to dislodge the buildup. If using this method, take care not to remove any material from the assembly itself. Photo below shows just how much was removed after one cleaning / drilling.
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    Clean the burner itself [sorry, no photos]. I used brake cleaner and compressed air. Just make sure there is no particles anywhere. Also used brake cleaner on the interior of the assembly after the drilling process.
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    Also notice that the end of the hard propane line also has some surface rust. I lightly sanded the surface until clean.
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    Remove the flue top, baffle, baffle hanger and clean all from surface rust. The flue top might have considerable rust. You may elect to spray paint yours. I’d recommend high temperature stove type rattle can paint.
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    I elected to replace the wire/holder for the baffle as the original one was pretty rusted. I simply used stainless steel safety wire shaped to resemble the original. The stainless isn’t prone to rusing.
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    Clean flue. I bunched up a small rag and pushed it through the flue a few times using an extremely long 3/8” socket extension.
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    Reinstall everything that you removed and barring any further problems, you should have a working refrigerator again on propane.
     
    Last edited: Jul 31, 2018
    Sjm9911 likes this.
  2. Pozi

    Pozi Member

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    12V and 120V switch cleaning

    One other maintenance item that I have been recommending lately is also cleaning the 12V and 120V switches. On my other PUP, there was a ‘buzzing’ sound coming from the 120V switch when energized. Upon further investigation, I determined that the switch contacts had become corroded causing an arc thus creating the buzzing sound. Below are steps on cleaning the contacts. You may also elect to simply replace the switches but the repair is super easy.

    I am willing to bet that this maintenance can be completed with the refrigerator still in the PUP but your results may vary.

    I elected to remove the panel via 2 screw securing it to the back of the refrigerator. The screws are located behind the piezo ignitor and 120V dial shown in the photo below. You’ll also need to remove the small hard propane line connected to the burner assembly to gain enough slack. The photo below shows the burner assembly removed since I was cleaning it at the same time.
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    Remove wires from the back of the switch. It’ll be helpful here to take photos or write down what wires go to what terminals. It’s extremely important for the 120V switch but not so much for the 12V as the polarity doesn’t matter according to the owner’s manual.
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    I recommend removing and cleaning each switch individually so it’s easier to manage the wires. To remove the switch, do so by using a flat blade screwdriver and gently push down on the tabs while rotating/prying the switch out. Once one end is popped out you can remove it completely by hand.
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    Using the same screwdriver, GENTLY pry the switch “handle” away from the body. It’ll take a little finesse but it’ll work its way out.
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    Remove metal thingamajig from within switch.
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    Using tool of your choice gentle scrape the metal on metal contacts inside the switch and on the little metal piece previously removed. Notice the corrosion on this switch even though it was working properly. It was only a manner of time before it stopped.
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    Reassemble switch. If you have di-electric grease apply it to the pivot of the metal interior piece and reinstall. Put the switch handle back into place. The 0 (off) side installs directly over the contacts/terminals.

    Repeat process with 120V switch. This switch will have two small metal interior pieces. Note just how much dirt was inside the switch when I took mine apart.
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    I hope this helps some users get one way of their 3-way refrigerators working again.

    Sorry about the extremely large photos. I'll try to change them to thumbnails in the next day or two
     
    Last edited: Jul 31, 2018
  3. Anthony Hitchings

    Anthony Hitchings Member

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    Xlnt - thanks so much, I will do that all before my 2 month trip
     
    Last edited: Mar 6, 2019
  4. Pnut

    Pnut Member

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    Good information. Thanks for the write up.
     
  5. Anthony Hitchings

    Anthony Hitchings Member

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    nice work; my long term plan is to add a relay pair so that the 120V thermostat also controls the 12V frig operation - it looks to be quite easy. But first - I need to do the same cleaning as you described so well above.
     

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