Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

Low Pressure Sensor / Switch: Description and Operation






The dual pressure switch prevents damage to the compressor in case of system loss and over of refrigerant charge. It is installed to the liquid line of the receiver outlet. This combines the high pressure switch with low pressure switch.

The high pressure switch cuts off the electrical power supply to the magnetic clutch when refrigerant pressure rises above the setting.

The low pressure cut-out switch senses low refrigerant conditions thus preventing damage to the compressor.