Dual Function Pressure Switch
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The dual function pressure switch is used to interrupt A/C compressor operation in the event of high system discharge pressures.
- The dual function pressure switch is mounted on a schrader-type valve fitting on the compressor manifold and tube assembly.
- It is not necessary to recover the refrigerant when removing the dual function pressure switch.
- A valve depressor, located in the threaded end of the dual function pressure switch, presses on the Schrader-type valve stem. This allows the dual function pressure switch to monitor the compressor discharge pressure.
- When the compressor discharge pressure rises, the switch contacts open, disengaging the A/C compressor. When the compressor discharge pressure drops, the switch contacts close to allow operation of the A/C compressor.
- The dual function pressure switch has a second set of electrical contacts used for high-speed cooling fan control. When the compressor discharge pressure rises, the contacts close and engage the high-speed cooling fan control. When the pressure drops, the contacts open and the high-speed cooling fan control is disengaged.