RV absorption type refrigerators rely on a sealed "cooling unit" to do
their job. There is the refer box, the heat sources (LP, 110V/12V
electric) the controls and the "cooling unit"
The cooling unit is a sealed, high pressure vessel containing water,
amonia and several chemical elements. Using one of the heat sources the
controls heat the contents of the cooling unit to a boil. Once boiled
the gas circulates through the freezer heat exchanger on to the lower
box heat exchanger and back to the collector. As the contents reliquify
they take heat out of the box thus cooling the interior. Cooling units
are not field repairable. They can be overhauled by a qualified shop but
must be handled carefully. The most common visible signs of a bad
cooling unit are a strong amonia smell in the box or a sulfur deposit on
the outside of the cooling unit.
The older cooling units, which are identifiable by the square chimney
enclosure are more sensitive to operating off level. The chimney can be
seen by opening the outside service access and looking to the right side
of the back of the refer. If the chimney is square then it is an older
design. When the basic design of the cooling unit was changed to improve
it's usability the chimney enclosure was changed to a round design.
Older style refers when left sitting in one place, especially unused
tended to "lock up" due to seperation of the contents components.
Operating off level causes a similar situation where the cooling stopped
circulating and "locked up" The first step in the Dometic service manual
for these situations was to "burp" the unit. This is done by removing
the unit from its enclosure and turning it up side down. When doing this
listen for a gurgling sound. It may be necessary to turn the unit over a
second time to get results. No gurgle, no fix. Need new refer.
I burped the refer in our 75 Argosy when we first got it. It would sort
of cool but not really well. Once burped it worked well for the
remaining two years we owned it. Of course removing a refer from an
Airstream/Argosy is much easier said than done. I had to remove 16
screws to get ours out because it was part of the cabinet structure.
Most older refer installs are similar.
Charlie
>
>Non operative refrigerators seems to be the ubiquitous discussion lately but
>ours in the 62 Globe Trotter came up inoperative this spring. I talked to
>the local RV repair who suggested banging on the fins and pipes, which did
>make it freeze, however it seems to need additional banging each time to
>make it function.
>
>I'm wondering if I need to replace a part somewhere? Any ideas will be
>greatly appreciated. GAS
>