Lennox 17W11 Defrost Thermostat 319847-401 and LB-74940A

and LB-74940A

this assembly utilizes automatic ball checks to prevent accidental media discharge in the event of glass breakage

Key Benefits Precise Flow Control: Specifically calibrated for 7

Does the 10-617-05 require specific mounting orientation

Direct Cross-Reference: Purpose-built to replace the Ranco 3030-601

Lennox 17W11 Defrost Thermostat 319847-401 and LB-74940AThe Lennox 17W11 Defrost Thermostat is a critical OEM replacement part designed to regulate the defrost cycle in high efficiency heat pump systems. Engineered for precise temperature monitoring, this Lennox L60 31F sensor prevents seasonal ice accumulation on the outdoor evaporator coil, ensuring consistent heat transfer and protecting the HVAC compressor from liquid slugging. As an SPST switch, it operates on a fixed temperature differential,