Carrier HH12HA163 Limit Switch the Johnson Controls FTG13A 600R is the Johnson Controls FTG13A 600R is a robust packing nut assembly designed specifically for direct mount thermal applications in closed tank systems The Emerson Alco 027511 Lens Assembly (Model X12978 1) is a critical service component designed for the upkeep and repair of moisture liquid indicators within commercial refrigeration and HVAC systems this 1 2 inch disc style switch provides reliable circuit interruption in the event of blower failure or restricted return air ensuring the system remains offline if an over temperature condition occurs until a technician can verify heat exchanger integrity and airflow