ActronAir Low Pressure Switch R22 800L/12S protects the R22 refrigerant circuit on Classic Series residential split ducted systems by cutting power to the compressor when suction pressure drops below the low-pressure set point, preventing compressor damage from operating in a low-refrigerant or restricted-flow condition. A failed closed low pressure switch removes protection from refrigerant loss events; a failed open switch prevents the system from starting even with a correctly charged circuit. Isolate power and recover refrigerant before replacing any refrigerant circuit pressure switches.