Lennox 74W77 Limit Switch 320788-702 Common indicators include the compressor

Common indicators include the compressor humming but failing to cycle

Tight Leakage Rating: Engineered to meet stringent shutoff requirements

including humidifiers and electronic air cleaners

technicians should replace this element when the pressure differential exceeds 10 psi or during annual maintenance cycles

This 1-speed assembly is optimized for heat-only applications

Lennox 74W77 Limit Switch 320788-702 Common indicators include the compressorThe Lennox 74W77 Limit Switch is a critical OEM safety component engineered for precise thermal regulation within Lennox furnaces and air handlers. This L155 30F limit switch is calibrated to open at 155F and automatically reset when the temperature drops by 30F, preventing heat exchanger damage and ensuring safe operational cycles. Designed as a direct Lennox 74W77 replacement, this high limit control utilizes a bimetal sensing element to monitor