Description
The Lennox 12L46 is an OEM-grade pressure switch engineered to deliver reliable draft-proving protection in Lennox furnace and air handler applications. Designed to monitor negative pressure created by the inducer blower, this switch confirms safe combustion venting conditions before allowing the ignition sequence to proceed — a critical safety function in modern gas furnaces.
Key Features
- Set point: .40″ water column (“wc) — factory-calibrated for precise pressure sensing
- SPST (Single-Pole, Single-Throw) switching action for straightforward open/close circuit control
- Dual 1/4″ barb connections for easy hose attachment to the inducer housing or collector box
- Direct OEM replacement for compatible Lennox furnace models
- Helps prevent furnace operation under unsafe venting or blocked flue conditions
- Durable construction built to withstand the thermal and pressure cycling demands of residential HVAC systems
How It Works
The pressure switch is connected via rubber tubing to the inducer blower housing. When the inducer motor starts and generates the correct negative pressure (at or beyond the .40″ w.c. set point), the switch closes, signaling the control board to continue the ignition sequence. If adequate pressure is not detected — indicating a venting problem, blocked condensate line, or failed inducer — the switch remains open and safely locks out the furnace.
Application
- Designed for use in Lennox gas furnaces requiring a .40″ w.c. pressure switch
- Suitable for residential heating systems
- Replaces worn, cracked, or failed OEM pressure switches
Specifications
- Brand: Lennox
- SKU / Part Number: 12L46
- Set Point: .40″ w.c.
- Switch Type: SPST
- Connection Type: Dual 1/4″ barb
Reviews
There are no reviews yet.