Econoline E350 1 Ton V8-5.4L Prop SOHC VIN Z (1998)
Refrigerant Pressure Sensor / Switch: Description and Operation
A/C Pressure Switch
A/C Cycling Switch
The A/C cycling switch is mounted on a Schrader valve-type fitting on the top of the suction accumulator/drier.
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A valve depressor, located inside the threaded end of the A/C cycling switch, presses in on the Schrader valve stem.
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This allows the suction pressure inside the suction accumulator/drier to control the operation of the A/C cycling switch.
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The electrical switch contacts open when the suction pressure drops to 152-193 kPa (22-28 psi).
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The contacts close when the suction pressure rises to 276-324 kPa (40-47 psi).
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When the A/C cycling switch contacts close, the A/C clutch field coil is energized.
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When the A/C cycling switch contacts open, the A/C clutch field coil is deenergized and compressor operation stops.
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The A/C cycling switch will control the A/C evaporator core pressure at a point where the plate/fin surface temperature will be maintained slightly
above freezing.
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This prevents icing of the A/C evaporator core and blockage of airflow.
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It is not necessary to discharge the refrigerant system to remove the A/C cycling switch.
