Date:         Sun, 9 Oct 1994 10:57:55 -0700 (PDT)
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         Wes Neuenschwander <wesn@eskimo.com>
Subject:      Re: Fridges, more rambling...

On Sun, 9 Oct 1994, David Schwarze wrote:

> Date: Sun, 9 Oct 94 02:11:53 CDT
> From: David Schwarze <schwarze@io.nosc.mil>
> To: Multiple recipients of list <vanagon@lenti.med.umn.edu>
> Subject: Fridges, more rambling...
> 
> pup outta there, but finally got it removed.  Once home, I hook it up to a
> battery and wait anxiously.  Nothing!  Start looking closely at the innards
> and I discover that it is NOT the type with a compressor, but has the heating
> element.  Arrrrgh!  Oh well, maybe it will still work alright.  Check the
> current with an ammeter and it is drawing 5.2 amps, just like it is supposed
> to.  Decided to let it run awhile and see what happens.  A half hour later
> the cooling finns inside the fridge start to feel a little cool.  I put a
> gallon of water inside and leave it for 6 hours with a thermometer inside.
> The thermometer reads 55 on the bottom of the fridge, water still warm, light
> frost on the end of the cooling fins.  I'll check back in the morning, and
> dammit that water better be at 33 degrees!
> 	Are all of the fridges in Westys the same way?  Or is this one
> messed up somehow?  Would a small fan inside help?  Would a small fan
> *outside* help?  I'd really like to use this fridge in my camper, but if
> it can't chill drinks, well...
> 
> -David
> 
> 
To the best of my knowledge, pretty much ALL RV fridges are of the 
"absorption" or 'non-compression' type.  These offer a couple of 
advantages, primarily that they can use propane as an energy source.  The 
principle of operation is pretty simple:  they use a chemical absorbant 
to sort of "suck" the refrigerant gas through the system vs using a 
compressor to push/suck the gas.  The heater is used to drive the 
refrigerant gas back out of the absorbant, restarting the cycle over 
again.  The problem is these tend to be pretty wimpy systems and they 
have a major startup lag as well (the heater had to come up to temp and 
drive off most of the gas before any cooling happens).  Of the three 
heater options typically available, the 12V system is by far the worst, 
both in lag and in power.  The 120V and propane (in my experience) are 
about equal and much better than the 12V.  However, absorption systems 
tend to deteriorate with age and it's likely that the unit you salvaged 
will be unable to perform like new, no matter what heat source you use.  
I'd try the 120V connection, giving it at least 12 hours.  You should be 
able to pull it down to 35-40F with an outside air temp of 70F with the 
thermostat set at Minimum (BTW, the thermostat typically only affects the 
propane and 120V modes;  12V mode just runs at max all the time - it 
needs to!)

--------------------------------------------
Wes Neuenschwander
Seattle, WA

(wesn@eskimo.com)