Yet Another Fridge Question

[kb1flr]

Hi All,

I have tried in the past to get the Dometic refrigerator working on my 1996 16 ft Casita using primarily AC with no good results. I finally got some free time this weekend to attempt running it on propane. It took a bit of cleaning, but I got the propane working and amazingly my refrigerator started cooling and got down to 32F. I was ecstatic and decided to let it run for a while.

After a few hours, I checked again and to my dismay, while the flame still seemed fine, the unit was warming. My theory is that the jostling from the last trip 3 weeks ago left the ammonia in a good state, but that just sitting, the aamonia was not happy. I took great pains to make sure the unit was as level as possible, so I am a bit at a loss.

Any help would be greatly appreciated.

Rick and Jessica

[Bob Miller]

Sounds like there is some "Stuff" circulating in the cooling circuit and it is collecting at the bottom of the absorber tank at a very small orifice that leads into the boiler. See here:

How 3-Way Fridges Work - Fridge FAQs Portable Fridges Camping Fridges

Your guess that everything got jostled around sounds like it has some merit. This is what sometimes happens when boxes that were run out of level extensively start going south. They will work for one or two cycles during a trip and then clog up again.

So I guess that the technique will have to be "Shake, don't stir".....

[RogerDat]

It may be that "sludge" has built up from precipitate in the ammonia. This can block flow of liquid and thus cooling. That would fit with your idea of jostling making it work but sitting causes a problem. As it runs stuff collects at a choke point.

You might want to Google or search the forum for "burping" an evaporative refrigerator. Essentially it is taking fridge out and laying on sides and back in a specific sequence to cause the blockage material to flow to a location where it does not cause problems. It may also have to do with migrating air bubbles, but on that I don't recall for certain.

Some folks say burping is a temporary fix that only buys some time for an otherwise failing unit others have said it fixed the problem for long enough to be considered a permanent repair. I guess it might depend on the situation causing the problem.