Originally Posted by edglenn
I just purchased a 1969 Overlander (still need to tow it home).
The owner "didn't know" if the fridge worked, so that probably means it doesn't.
I'm sure I can get it working, but I'd like to research this particular model fridge.
Where can I find literature for this unit?
Is this Ammonia based?
What parts typically wear out, and what needs to be cleaned/serviced?
Will this run on 12 VDC, or only 120 VAC?
I haven't checked the propane system for leaks yet.
How cold do these fridges get?
There's a glass level on the face of the fridge, which means it needs to be level to work properly. Does this mean the fridge won't operate while the trailer is in motion?
p.s. I just joined this site. Very nice!
*IF* it's the original fridge, it's ammonia-based and designed to work on propane or 120V, and has no 12V
at all. Check the model number to see if it's the original or a replacement that could either have a 12V
control system or (less likely) be a 3-way unit.
Older ammonia-absorption fridges are sensitive to being level. When in operation during towing, the motion of the RV is enough to keep bubbles from collecting in the wrong place, but when parked they should be leveled.
When they're operating well, these old RV fridges usually will freeze things really well, but sometimes the refrigerator compartment will only maintain a "cool" environment on its own. The freezer gets the refrigerant first, and when outside temps are high there sometimes isn't enough capacity remaining to chill the refrigerator side. There are several tricks that are helpful with this, such as switching cold packs (plastic soda bottles with frozen water, e.g.) between the freezer and refrigerator compartments and keeping the refrigerator relatively full, since lots of the chilled air in the compartment escapes when you open the door, but the mass of cold food and beverages stays and helps the refrigerator "catch up" more quickly after you close the door.
The main thing to remember is that they're slow to come down to temperature, so you should start your refrigerator cooling a day or two before you plan to leave on a trip.
Newer ammonia-absorption RV fridges are a little more efficient (better insulation, better controls, etc.) but not enough to make it worth replacing a working older unit, especially at the prices new units command.
As to parts that wear out, the original fridges on our older trailers are very simple. There's a mechanical ignitor, a gas burner, and an electrical heating element. Gas burners get dirty, the "flint" in spark ignitors wears out, electrical heating elements burn out and gas flues sometimes have spider or mud-wasp nests built in them. All these things are easily corrected, if not always easily detected. The real killer for absorption fridges is a breach of the ammonia system. If that's rusted out or otherwise has a hole in it, you'll need either another cooling unit (expensive) or a whole new fridge (even more expensive). My impression is that you can find the replacement cooling units for $400ish, and people have had mixed results with replacing them. New RV fridges are $1200+