Maintenance & Restoration

Grant Jones · 09-01-2015, 09:39 AM

I have a Dometic AM24, which is an old original refrigerator. The PO said the unit did not work on propane, only electric. Knowing how the refrigeration works in these, that made me very suspicious of a couple of items on the propane side. I tried to light it. It would stay lit for a very short time, then go out. This is how a weak thermocouple behaves. I chased around to the RV shops and found a replacement thermocouple ($20). Physically replacing it took an afternoon, but that did the trick. Several other people have pointed out, these refrigerators are very slow compared to the household ones. The "dish of water test" is a good one and will give you an idea of performance.

The Minimalist · 09-01-2015, 05:15 PM

"dish of water test"? Elaborate please.

Grant Jones · 09-01-2015, 05:50 PM

Place a shallow Tupperware dish (or an ice cube tray) in the freezer compartment. From a warm-started refrigerator I would say in about 3 hours you should see it half frozen...in 6 completely frozen. Then you know things are working. To speed up the process, some people put frozen cold packs in there. I just leave my running even when i am going down the road (which is frowned upon!).

The Minimalist · 09-01-2015, 06:06 PM

OK. The RM2193 in the Little Joe doesn't have a freezer compartment, but if the ambient temp isn't above 90 degrees F you can turn the whole thing into a freezer compartment.

For efficiency I look for a delta of at least 40 degrees F below ambient. Except when it's 90 plus I run about 50-53 degrees below ambient.

I run the road with mine on propane, with proper precautions at filling stations of course.

I am getting ready to make a foam dam that will fit inside the door at the bottom, so when I open the door all my cold air doesn't dump. I'll keep the colder things down there and not loose all the cold when I reach inside for an IPA.

tractors1 · 09-01-2015, 06:58 PM

Quote:

Originally Posted by The Minimalist

OK. The RM2193 in the Little Joe doesn't have a freezer compartment, but if the ambient temp isn't above 90 degrees F you can turn the whole thing into a freezer compartment.

For efficiency I look for a delta of at least 40 degrees F below ambient. Except when it's 90 plus I run about 50-53 degrees below ambient.

I run the road with mine on propane, with proper precautions at filling stations of course.

I am getting ready to make a foam dam that will fit inside the door at the bottom, so when I open the door all my cold air doesn't dump. I'll keep the colder things down there and not loose all the cold when I reach inside for an IPA.

In the last week there were posts on escapeforum.org for a product that uses vertical vinyl strips across fridge as a partition you could reach through to get stuff out of the fridge without losing all the cold. Old method from produce warehousing so fork lifts could drive thru, adapted to small fridge use. Pretty cheap (<$30) as I recall.

greenghost45 · 09-01-2015, 07:21 PM

One of the advantages of the compressor portable fridge that we used on our sailboat was that it was a chest style with top opening lid; very little loss of cold when you opened it. You can improve the efficiency of a front opening fridge by keeping it full, even if you have to add stuff such as extra juice boxes, beer etc. Simply put, the less empty space and air in the fridge, the less cold you lose when you open it, and less warm air replaces the cold air. Also, filling the fridge with pre-chilled juice boxes from home will help the cause.

Byron Kinnaman · 09-01-2015, 07:53 PM

Quote:

Originally Posted by Glenn Baglo

Unless, of course, it uses 12V for the control circuit.

Agreed. Those control units are pretty hungry from my understanding. Don't have one, no battery required for my propane fridge.

steelypip · 09-02-2015, 08:16 AM

Another thing about old vs new fridges: If it's the usual ammonia absorption type, the refrigeration technology hasn't changed since about 1960.

This is not to say that there haven't been some improvements since then, most noticeably in the fridge's response to being off-level in propane mode, but there's not a lot to choose between the cooling capacity of a 1985 or 1990 fridge and a current model. They haven't gotten more efficient, but they have gotten more complex. I happen to like very much that my RM2201 is completely manual and uses no 12V power at all unless I want it to.