This switch is calibrated to close the circuit at 257 PSI and open it at 126 PSI

the HK35AA009 is the current OEM substitute for both the HK25AZ070 and HK25AZ080

and ensure your motor rotation is clockwise (CW) when looking at the discharge side

Integarl Mounting Flange or Strap and Bracket for Duct Mounting

and normally closed (NC) terminals to ensure the circuit closes upon a temperature rise for cooling stages

Lennox 56W21 Limit Switch 318820-201 This switch is calibrated toThe Lennox 56W21 Limit Switch is a critical safety component designed for precise thermal monitoring in high efficiency furnaces and air handlers. This L160 30F limit switch is engineered to open the electrical circuit at 160F on a temperature rise and feature an automatic reset once the plenum cools to 130F. As a veteran grade HVAC replacement part, it is a direct match for the Lennox 46105 002 and is compatible with a wide array of Allied Air brands