Lennox 27W17 Pressure Switch WC SPST Normally Open - 0.85

The Lennox 27W17 pressure switch is a critical safety component designed for use in HVAC furnace and heating systems. This normally open, single-pole single-throw (SPST) pressure switch monitors air pressure differential to ensure proper draft and safe operation of gas-fired heating equipment.

Key Features:

• Pressure setting: 0.85 inches water column (WC)
• SPST normally open contact configuration
• OEM Lennox replacement part (replaces 101256-01)
• Monitors induced draft blower pressure for safe furnace operation
• Prevents burner ignition if proper draft is not established
• Quality-tested for reliable performance and longevity

This pressure switch serves as a safety interlock in the furnace control circuit, closing its contacts when adequate negative pressure is detected from the draft inducer motor. If proper pressure differential is not achieved, the switch remains open and prevents the ignition sequence from proceeding, protecting against potentially dangerous flue gas spillage. Essential for maintaining safe and efficient heating system operation.