It's very possible the start relay is bad. Not a likely
problem, as it does run for a few seconds or moments. Sounds
more like the compressor berrings are worn out, and the
internal friction is too great for the motor.

If the problem were dirty condensor, the compressor would be
too hot to touch. You ruled out several of the other
possibilities.

There are hard start kits made for compressors, but might
not be worth the bother. An appliance shop may be able to
fit it with a hard start kit. And, it may keep doing the
same problem.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"terry" wrote in message
...
Some advice please.

Smallish floor mounted dehumidifier on casters, about size
of a small
filing cabinet.

The colour and style of the overall unit suggest it was the
sort of
thing sold by say Sears some 20+ years ago. (We also have a
newer one
that is very similar but different colour and details).

Problem. Compressor runs but after a few minutes cuts out.

Problem has been tracked down to the compressor itself.
It's a
typical fridge type sealed compressor. The compressor is
marked as
follows;

"aose a" , "115 v 60 Hz", also "A5160A 144CG25". The
compressor is
also labelled "Thermally protected".

After checking and bypassing all other parts of the circuit
(the
humidistat, drip pan float switch and some sort of 'cut-out'
clipped
to the output end of the cooling coils are all OK) it is
found the
compressor runs but shuts down after several minutes without
getting
particularly warm!

On the side of the compressor, plugged into two of the three
pins
projecting from the sealed unit, is a typical compressor
starter
relay marked [FSP] "920235" and "960A042-172" and "P4S".

Adjacent to the starter relay under the same cover and in
series with
the hot lead from supply to the starter relay is a round
bi-metal
device which the mounting clip presses against the outer
surface of
the compressor. It is marked Klixon and "MR26ALK-3164" and
"T.150-IK45
[FSP] 950234".
We presumed this circular device to be a bi-metal thermal
protection
switch. However when it is temporarily by-passed the whole
unit runs,
the cooling coils start to form frost but the compressor
still cuts
out after a few minutes.

Is there another thermal protection circuit inside the
sealed unit????
And if so there is presumably no way for a DIYer to fix it,
nor would
it be worthwhile/safe to attempt. Correct?

We were going to chuck this unit but decided to give it
another try
before doing so. Any knowledgeable advice would be most
welcome.TIA.

BTW the unit is marked R12 (refrigerant) so if we dispose of
it we
will call the Environment/Recycling people to determine
where to take
it.

Although in one middle - eastern country where we were for
several
years have seen car AC systems 'serviced' by letting the
refrigerant
blow off and then recharging the whole thing!