Lennox 26W46 Pressure Switch

The Lennox 26W46 Pressure Switch is a critical safety component designed for two-stage gas furnaces, engineered to monitor the venting pressure and ensure the inducer motor is operating within specified parameters. This specific differential pressure switch features a dual-setpoint configuration of 0.65" WC and 1.15" WC, facilitating the precise monitoring required for both low-fire and high-fire heating cycles. Built to meet OEM Lennox specifications, the 26W46 acts as a fail-safe mechanism, preventing the ignition of the gas valve if the combustion air flow is insufficient or if the vent pipe is obstructed. It replaces multiple legacy part numbers, providing a reliable solution for maintaining HVAC system efficiency and preventing pressure switch lockout codes. When diagnosing furnace diagnostic flashes, this switch ensures the combustion blower is clearing the heat exchanger of flue gases before allowing the sequence of operation to continue.

• Dual-Stage Calibration: Pre-set at 0.65" WC and 1.15" WC to ensure accurate gas furnace pressure switch operation across high and low stages.
• OEM Compatibility: Direct fit for numerous Lennox, Armstrong, and AirEase units, ensuring standard mounting and electrical terminal alignment.
• System Safety: Prevents hazardous operation by verifying proper exhaust venting and combustion air intake.
• Industrial Durability: Constructed with high-grade diaphragms to resist thermal fatigue and environmental debris within the cabinet.

Common Questions

What causes a pressure switch to stay open?
An open switch usually indicates a restricted flue, a failing inducer motor, or moisture buildup in the sensing lines. Verify that the vacuum tubing is clear and the orifice on the collector box is not clogged before replacing the 26W46.

Can I use a single-stage switch to replace this 26W46 model?
No. This is a two-stage pressure switch. Using a single-stage component will prevent the furnace from cycling correctly between heat stages and will likely trigger a control board fault code.

How do I test the 0.65/1.15" WC setpoints?
Use a digital manometer in series with the inducer's vacuum line. Observe the inches of water column at which the switch closes its contacts during both startup and high-fire transition to ensure it matches the 26W46 factory specifications.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.