Lennox 59W40 Proving Switch 321702-401 The sensing element utilizes a

The sensing element utilizes a high-durability pressure-actuated bellows to manage a broad operating pressure range of 50 to 500 psi

When you're troubleshooting a call where the Heil furnace blower motor won't engage or is staying energized way past the cycle

helping contractors distinguish between mechanical failure and electrical coil issues

The Sterling 11J38R06891-003 Ignitor is a heavy-duty OEM replacement spark igniter engineered specifically for technical compatibility with gas-fired unit heaters

For technicians performing burner repair or preventative maintenance

Lennox 59W40 Proving Switch 321702-401 The sensing element utilizes aThe Lennox 59W40 Blower Proving Switch is a critical safety component designed for specific Lennox furnace models and air handling units. This negative pressure switch is calibrated to a precise . 15" WC setpoint, ensuring the inducer motor or blower assembly is generating sufficient draft before allowing the ignition sequence to proceed. As a genuine Lennox replacement part, the 59W40 ensures seamless integration with the existing control board