39 year old Dometic Refrigerator

[BobbyW]

Well I fired up the 39 year old 2 way Dometic Refrigerator tonight for the first time in who knows how long. I have had the Globetrotter since December 2000 and had never tried it. It sat for many years when I had found it. The PO had never used it. Good thing....

Since it is freestanding while the interior is in rehab, I decided to look it over and see if it worked. Checking the power cord, I could see it was totally dried out and fell apart in my hands. The wires were all melted together. If it had been powered up, it would have easliy shorted....or worse. Replaced it with a new wire and plug.

It works, at least on AC. Temperature in the fridge part went down to 38 . I had put an ice tray in the tiny freezer and it made ice cubes. It took about 4 hours. Pretty amazing

Propane is next, after a good cleaning.

[eubank]

Originally posted by BobbyW
Well I fired up the 39 year old 2 way Dometic Refrigerator tonight ... (snip, snip) ... It works, at least on AC. .. (snip, snip) ... Propane is next, after a good cleaning.

Well, maybe there's hope after all! We've run our 67 fridge many times on propane (it gets cold!), but have never tried it on electricity. The cord looked ok (last time I looked). Maybe it's worth a try!

Lynn

[ScrapIrony-2]

Got our '68 Overlander last month...the propane cooling works very well (my damp hand stuck to the freezer compartment floor), but the electrical part does not. When I removed the access panel, the plug-in receptacle behind the fridge tested + for power(110AC). The power wire runs from the plug to a rectangular black box, and thence to the switch(yes, I did turn it on). I'm guessing that the black box is the culprit, and am wondering if this is a find-able part...also wondering what the box IS...will use propane for now, and be glad that that part works, but would really like to be able to pre-chill off a landline the night before leaving. Does anyone out there have a similar encounter, or expertise with this poser?........tracy's husband(mike)

[TomW]

Originally Posted by ScrapIrony-2

... I'm guessing that the black box is the culprit, and am wondering if this is a find-able part...also wondering what the box IS...Does anyone out there have a similar encounter, or expertise with this poser?

Mike,
Most RV refrigerators cool with ammonia absorption refrigeration. It is a neat process (at least to a thermodynamicist ), but you do not need to understand it to solve your problem. The only thing you need to concern yourself with is supplying a heat source to power the process.

Offhand, I would say you and I have the same refrigerator. When you run the unit on LP, the heat source is a flame controlled by a thermostat. When the thermostat commands 'cool', more gas is supplied to the flame making it bigger. When the thermostat indicates 'cool enough', the extra gas is cut off leaving just a pilot. So, you have either a pilot, or a more robust flame i.e. cooling is either ON or OFF.

When you run the unit on shore power, the heat source comes from a 230 watt heating element controlled by a totally separate thermostat. When cooling is desired, the heater is ON. The heater is OFF when no cooling is desired. Again, there are no degrees of ON or OFF.

The heating element package looks somewhat like a fat cigar, and is not repairable. In fact there is no reason to pull it out unless you plan to replace it as there are no electrical junctions on which to hang a meter. I assume what you are calling the "black box" is the enclosure on which one of your two thermostat knobs is mounted. You should see your power wires going in to the box, and the heating element wires leaving the box. Gain access to the inside of the box, turn the thermost down to its lowest setting, and see if the wires leading to the element have 120 VAC. If they do, the element is bad, if they do not, it sounds like the thermostat is bad.

If you have long, skinny arms, you may be able to replace the heating element without removing the refrigerator. I doubt you will be able to service the thermostat in place simply because the non-detachable probe is mounted out of reach.

I currently have my Dometic sitting on the shop floor while I finish the new floor covering (do you realize that these units comfortably hold two cases of ...beverage? ) Let me know if I can supply a picture or something to help your effort.

Tom

[wayner1239]

Ever wonder why the old reefers last so long and the newer ones go out in just a few years? The Dometic that came in my unit lasted about 9 years before it started smelling like ammonia. The fact that the old ones last almost forever tells me that the new ones are not made as well.
Wayne

[ScrapIrony-2]

Tom,
Thanks for the excellent lesson. I had planned on taking on the fridge thing today, but woke up to overcast skies and snow falling...a little cooler than I prefer for a work environment, and it's hard to tell if the fridge is working or the outside temp is working... I will aim for the weekend.......mike

"A nice thing about living in a small town is that when you don't know what you're doing, someone else does..." UNK

[Safari Tim]

Can anyone explain exactly how to clean the burners in the fridge? I have new Dometic I put in a couple of years ago and I know your supposed to clean the burners once a year, but I don't have any idea what that really means.

[TomW]

Originally Posted by Safari Tim

Can anyone explain exactly how to clean the burners in the fridge? I have new Dometic I put in a couple of years ago and I know your supposed to clean the burners once a year, but I don't have any idea what that really means.

Tim,

The one burner in the fridge has a course mesh screen over it to keep chunks from falling in and clogging the jet. Just vacuum it. If nothing else, its a good time to check flame color.

I think what you might have heard deals more with cleaning the flue on a regular basis. In my Overlander, it goes like this: On the countertop on top of the fridge, there is skinny cabinet suitable for not much more than drying dish cloths. But there is also a an access plug to get to the top of the flue.

Remove the plug, and you will see the top of the flue loosely covered with a round metal plate. Pull up on that, and you will find the top connects to a twisted piece of flat stock. I believe it is a baffle there to help the heat of the burner be absorbed by the fidge's working parts. If your flame is too yellow, soot can build up on the baffle. Since soot is unburned solids, the concern is that a large accumulation has the possibility of catching on fire, like a chimney fire.

Although the baffle should be checked on a regular basis, the flame should be checked even more often. Too much yellow in the flame (too much air) will cause soot, whereas too little air will make the flame noisy.

Hope this helps,
Tom

[26.982 amu]

I couldn't resist crowing about this--I am amazed! I finally got around to working on the OEM Dometic refrig in my '72 Ambassador. I plan to mostly boondock, so the propane system is all that I worked on (cleaning). The quaint flint striker lacked a flint, so I broke open a spent butane lighter, retrieved the flint, and installed it in the striker--works perfectly!

I still can't get over how that tiny little flame produces 38-degree cooling and freezing temps for ice cubes! I hope everything else in this tin bucket works as well!

[lewster]

Tim,

Tom did a pretty good job of explaining the workings of the cooling unit.
Good job, Tom!

There are several other things that you should check/clean while you have the burner tube apart. Run a brush thru the tube to clean it thoroughly. Remove the burner orifice and look thru it. Blow some compressed air (ONLY!) thru it to remove any possible obstructions and do clean the baffle (the spiral piece at the end of the wire that Tom mentioned). A light sanding or stiff wire brush will do nicely. Vacuum the residue annd re-assemble. Your flame should be a nice bright blue. If not, the gas/air mix should be adjusted at the air inlet.

That should keep it running fine for another year. BTW, the black box on the
current models control the direct spark ignition of the gas burner (you don't have this) and the opening/closing of the gas valve. I would suspect that a vintage unit would have a thermocouple in the path of the burner to do this task.

Let me know if I can offer any more help. You also might try the Dometic web site for any pertinant docs.

[C Johnson]

Originally Posted by wayner1239

Ever wonder why the old reefers last so long and the newer ones go out in just a few years? The Dometic that came in my unit lasted about 9 years before it started smelling like ammonia. The fact that the old ones last almost forever tells me that the new ones are not made as well.
Wayne

Well yes at first I did, now I am just happy my 40 yr. old dometic still works !
34* last trip and ice cubes too.

[53flyingcloud]

Originally Posted by C Johnson

Well yes at first I did, now I am just happy my 40 yr. old dometic still works !
34* last trip and ice cubes too.

Got you beaten by a long shot..The "original" frig in the 64GT still cools down a six pack quicker than anything~
Your welcome to sample the beer anytime...lol
ciao
53FC

[SafeHarbor]

The original fridges in my '75 Argosy and '79 Excella are still running, too. On both of them, I had to replace the electrical heating element soon after purchasing the trailer. I've found that pplmotorhomes in TX is a good source of them.

Lamar

[jazzman]

LEW,I was told to remove my 68 dometic and turn upside down to fix the vapor lock. I removed the wood panel and the floor bolts and 1 large wood screw, but I can't get the unit to move. Is ther any attachment on the oven side? Please help. I also want to use the electric side only, can I remove the gas lines completely?

[26.982 amu]

Originally Posted by Vince Brach

I couldn't resist crowing about this--I am amazed! I finally got around to working on the OEM Dometic refrig in my '72 Ambassador. I plan to mostly boondock, so the propane system is all that I worked on (cleaning). The quaint flint striker lacked a flint, so I broke open a spent butane lighter, retrieved the flint, and installed it in the striker--works perfectly!

I still can't get over how that tiny little flame produces 38-degree cooling and freezing temps for ice cubes! I hope everything else in this tin bucket works as well!

Well, I'm eating my words now. I checked my fridge after a week--NOT RUNNING. The burner is still burning, but there is no cooling going on. The bubble level is right in the circle, too. What could be wrong?

[65glbtrotter]

Originally Posted by lewster

Tim,

Remove the burner orifice and look thru it. Blow some compressed air (ONLY!) thru it to remove any possible obstructions.

My fridge in my '65 Globetrotter quite getting cold last year and it ended up being the orifice was a little plugged, flame still there just not enough to heat it up. So that is what I would look into.

[lewster]

Originally Posted by jazzman

LEW,I was told to remove my 68 dometic and turn upside down to fix the vapor lock. I removed the wood panel and the floor bolts and 1 large wood screw, but I can't get the unit to move. Is ther any attachment on the oven side? Please help. I also want to use the electric side only, can I remove the gas lines completely?

You've got a PM

[26.982 amu]

I'm trying real hard to avoid exasperation with my Dometic refer. The freezer freezes, but the food compartment simply won't cool. The exchanger on the inside gets ice on the right where the pipe comes in (as you look at it) but the fins are hardly cool at all.

Outside, the pipes on the back of the unit are quite hot to the touch and the propane flame is sky blue and vigorous. What on earth could be the problem?

[TomW]

Remember that your Dometic has no forced air like your home's fridge does. Off-hand, based on your presentation, I would suspect the door gasket or another thermal leak.

But have you left a thermometer in the food compartment overnight to get straight scoop?

Tom

[26.982 amu]

I put a little muffin fan in it, blowing on the cooling fins, to see if that would aid the cooling process. NO DIFFERENCE after 24 hr--outside temp 80F, inside 60F.

It may be that the old door seals are leaking cool air, but I put bicycle grease on them all the way around for a "temporary fix" and the result was NO DIFFERENT.

My unit seeems to lack a topside opening for a flue cleaning brush. What I have is a buret brush--basically a test tube brush with a meter-long wire handle. Is there some way to run this up through the flue from underneath?