"Don Young" wrote in message
webinternetservicesprovideinc...


Follow up.

Well it is NOT the compressor internal or external thermal
cut-out/
protection; I should have realized earlier there IS another
element in
the circuit!

Most of the controls, humidistat, drip pan float switch,
etc. are in
the live lead to the compressor circuitry. However there is
one item
which appears to be some sort of temperature sensor which
is/was wired
into the neutral side of only the compressor!

It is circular, sealed, has no means of adjustment and was
clipped
onto the exiting end of the cooling coils.

CY: Sounds a lot like a freeze stat.

The printing on it is very faint but appears to be "37T32
29531 59-20"
Also "F?20009-052 and 201?M?73" But that last group of 8
characters is
very indistinct indeed.

After removing it the rest of the unit operates fully, it
starts
normally and frost quickly forms on the cooling coils. So
the
immediate conclusion was that this 'cold control' switch is
maybe
faulty or operating too soon at too high a temperature?

CY: Perhaps. Since the freeze stat trips too soon......

So a question might be; is this gadget supposed to open the
compressor
ctcuit to allow, say, the coils to periodically defrost
and/or is it
opening at much too high a temperature.

CY: If it's what I think, it's to prevent the evaporator
coil from turning into a block of ice. The coil only needs
to be in the thirties or forties to condense water out of
the air.

If opening at too high a temperature maybe it should be
reinstalled
and located differently so as to not operate so soon?

Any further advice most welcome.

CY: Might be the unit is low freon, and getting cold too
fast, or the freeze stat is too sensetive. I'd be tempted to
try a couple wraps of electrical tape around the tube, and
then put the freeze stat back on. Maybe that will slow it
down.

Also the knob is broken off the humidistat but that can be
repaired.
Adjusting the humidistat (basicall a micro-witch with a
sensor) shows
that it is working.

Further advice welcomed.

I have not read this entire thread but it seems to me that
your unit might
be low on refrigerant. I don't think the coil temperature
should be below
freezing (frosting). If the coil is frosting at the inlet
(small pipe) end
and is a lot warmer at the other end, it is almost surely
low on
refrigerant.

CY: It's normal to frost a bit where the cap tube goes into
the evaporator. But, most or all of the evaporator (cold
coil) should be cold.

Don Young