Help with non working 12v fridge

[austinado16]

Hi all,
I'm new here.  Just bought an '87 Starcraft Nova and am going through it and putting it back into shape.

Now that I've got the 12v electrics working, I tried to test the 2 way Dometic fridge today (on 12v).  After about 15min, the heat chamber was definately warm to the touch, but the evaporator inside was not cooling off at all (as measured with an infrared temp gun).

The camper isn't completely level, so I'm guessing that could be part of the problem, but I thought I'd at least see some change in temp in the coils inside the fridge.  Am I wrong?

I don't have propane in the new tank yet, so can't test it that way.  

Can the evaporators break and leak out all the amonia?

Any help would be greatly appreciated.

[mike4947]

Yes they can and they can also crystalize which means the working fluid has crystalized and blocked up a fluid chanel and prevented the fluid from circulating. On that old a fridge the error of out of level is only 1 DEGREE before you start getting crystals forming. So before you do any more testing level the trailer. Any crystals formed can not be redissolved, so it is a progressive problem.
Also it takes from 4-6 hours to actually "get cold" and 3 way or rare 12 volt /propane fridges are only designed to use 12 volt in transit as it only provides apx 1/2 the BTU's of 120 volt or propane and will drain a battery in just a few hours.

[austinado16]

Thanks Mike.  Wow, 1 degree.  I'll level it, get the propane on board and see what happens then.

One thing I noticed when running my fingers along that main evap tube inside the fridge is that in the back corner where the tube makes a 90, the tube is split length-wise, top and bottom, right at that 90 degree bend.  So, if that tube isn't an outer casing of some sort, and not the actual amonia gas "container" I'd say the evaporator (and probably the fridge in general) is ruined.

Are they repairable or is it not worth messing with on a fridge this old?

Will a "modern" one fit the existing hole and the vent panel/access panel on the exterior?

Any modern fridge's better than others if I do have to replace the whole thing?

[mike4947]

Could very well be done for. As for rebuilding or buying a rebuilt cooling unit. On our small fridges the cost is at least 80% of a new unit and seeing as how the new one comes with usually a 3 year warranty and the rebuild a 90 day warranty there's not much question of which way to go.

As for replacement measure the size after pulling the old fridge and look up what size requirements both Norcold and Dometic have for their current offerings. We've found that a lot of times with a little "pruning" of the face wood we could put in the next sized larger unit than was originally installed.
 
If you only camp with hookups a cheaper alternative is a dorm style fridge. They make ones capable of installing in the volume of the original fridge at a fraction of the cost of a three way absorption fridge.

[cruising usa]

Check out this site http://www.rvcool.com/ they might be able to help.  Lots of good info on how they work.
Good Luck

[Old Goat]

I have never used the 12 volt option on our Dometic fridge in our 01 Niagara. WE don't dry camp so there is no need to use the propane either. I fire it up now and then just to make sure it works just in case we ever do need it. If the fridge ever goes bad I will replace it with a small 110V dorm fridge that will fit in the same opening. There are several different makes that are very good and much cheaper than a new three way.....

[tknick]

the dorm fridges also cool a lot better and a lot faster.  the three way fridges are not designed to cool things down quickly (like drinks or leftovers from dinner).  they are primarily designed to keep cold things cold.  the 120v dorm fridge's compressor can actively cool things.  if you don't dry camp, the dorm fridge is the cheaper and better alternative.  if you dry camp then you don't have much choice.

travis