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Old 05-27-2002, 10:15 AM
Arthur Dalton Arthur Dalton is offline
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Join Date: Aug 1999
Location: Florida / N.H.
Posts: 8,784
Another note on the subject:

Be aware that the low fan is set to engage when there is a "High Thermal Load."
What this means is that if you have high ambient temp/humidity,
the high side pressures get to the point of cut-in pressure and the fans added air across the condensor helps drop this high pressure. The thing to know here is that if the system is not being Taxed/Burdened, than the a/c will run fine WITHOUT the low fan being called for.... so don't expect low aux fan if the ambient temp/humidity [ read LOAD here] are low..
this circuit is a safty valve for extreme conditions.
Some newer models use fan regardless of high side pressure,
but yours is not one of this design. [ I like this better]

The correct way to test the switch is with gauges on the high side for pressure readings and a continuity test for cut-in/cut-out specs. at the sw. connector.
This will eliminate the false diagnoses I mentioned earlier.

I might also mention that the confusion of calling this switch a temp one may come from the part sometimes being refered to
as a temp a/c switch as to not confuse it with the freon /compressor high pressure cut-out sw. when ordering.
But in reality, it is a pressure switch with bar ci/co, not
Centigrade temp...
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