The thermostat on my Adler Barbour small vertical evaporator stopped doing
its job last week. It did not turn off the compressor when the box got cold
like it used to.

Today it magically started working again. Why did it do so?

It must have had something to do with the fact that I added some more R134a
refrigerant to the system. The only thing I can think of is that enough
refrigerant had slowly leaked out over a period of four years to the point
where there wasn't enough left in the system to cool the evaporator
sufficiently at the area where the sensor tube from the thermostat attaches
to the evaporator which is at the tail end of the system as seen from the
point where the copper tubing attaches to the evaporator.

Adding refrigerant apparently allowed the box to get sufficiently cold at
the sensor attachment point whereas it was not getting cold enough there
with insufficient refrigerant in the system. BTW, I added perhaps two
ounces. There is now 15 PSI on the suction side fitting. 13Volts, 4.9 amps.
(Solar panels operating at optimal on sunny day) Ambient temperature 70
degrees F.

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

Wilbur Hubbard

"Wilbur Hubbard" wrote in news:49219ae7$0
:

Today it magically started working again. Why did it do so?



The contact arced, cleaned itself as it is designed to do, and contact was
restored as it burned away the corrosion.

On Mon, 17 Nov 2008 16:58:08 +0000, Larry wrote:

"Wilbur Hubbard" wrote in news:49219ae7$0
:

Today it magically started working again. Why did it do so?



The contact arced, cleaned itself as it is designed to do, and contact was
restored as it burned away the corrosion.

Or maybe a mouse was in there - chewing.

--Vic

"Larry" wrote in message
...
"Wilbur Hubbard" wrote in news:49219ae7$0
:

Today it magically started working again. Why did it do so?



The contact arced, cleaned itself as it is designed to do, and contact was
restored as it burned away the corrosion.


Good theory but turning the knob manually to the off position turned the
unit off. So if it were dirty and needed to be arched a few times it would
not have turned off manually would it? BTW, I can see the contacts working,
they are in plain sight when looked at from the back side. They look clean
and coppery.

Wilbur Hubbard

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.

"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