"Sam Goldwasser" bravely wrote to "All" (19 Nov 04 08:08:25)
--- on the heady topic of " AC defrost"

SG From: Sam Goldwasser

SG "NSM" writes:

"H. R. Bob Hofmann" wrote in message
om...

| Maybe it is a sensor to shut the airconditioner down in case the
| temperature gets too cold and there is danger of too much frost/ice on
| the cooling coils, or maybe a shutoff if the compressor temperature
| gets too high. You don't say where this sensor is located, as far as
| I can tell.

From "clips onto the cold end return" I assume it's on the input to the
compressor.

SG I expect it is a sensor to shut down the compressor if ice forms since
SG that's a runaway situation - once the ice is present, more ice will
SG form until the evaporator is a solid block of ice and no cooling of
SG the room takes place.


Yes, I think it is there to keep ice from building up on the room
radiator fins. This is Canada after all, and though the days are very
warm in the fall, the nights get cold. I wrote the sensor clips onto
the radiator return line but I was mistaken, it is the pipe that
brings the cold coolant into the room radiator. Sorry for the mixup.

What I still don't know is if the defrost interrupter contact is used
in normal operation or if it is simply a fail-safe device in case of
an abnormal event like the main thermostat getting stuck? It is too
cold to test right now and I don't know if I should go looking for the
part if it isn't really needed.

A*s*i*m*o*v

.... If all else fails, hurl it across the room a few times!