"Wayne.B" wrote in message
...
On Mon, 17 Nov 2008 11:24:55 -0500, "Wilbur Hubbard"
wrote:

So, the lesson is before you buy a new thermostat check your system
pressure
to make sure there is optimal refrigerant in it.

You can buy an IR gun type thermometer for a very reasonable price at
NAPA which is useful for checking all kinds of things. To properly
check refrigerant level you really need a full set of gauges to see
what the high pressure side is doing while you observe the sight glass
on start up.


There's no sight glass on my Adler Barbour Cold Machine. Just two ports with
Schrader type valves. One for suction side at the compressor and another for
return side. I added an adapter from NAPA to the suction side to fit the
standard R134a auto air conditioner fill. Interdynamics sells a 10.25 oz can
of Refrigerant at K-Mart that has the hose and trigger built in and it can
be used a little at a time without all leaking away. It must have a Schrader
valve built in unlike the standard cans where the adapter pierces a metal
seal.

In lieu of a pressure gauge one can use an amp meter. The amperage load
should be around 4.5-5.0 amps at 13 volt. Less than that and the refrigerant
is low, more than that and it's too high.

Wilbur Hubbard