Lennox 59W40 Proving Switch 321702-401 the Bard 9043-411 is designed

the Bard 9043-411 is designed for continuous duty cycles in demanding commercial environments

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

helping contractors distinguish between mechanical failure and electrical coil issues

For technicians performing burner repair or preventative maintenance

How do I test a BASO K16RM-96 thermocouple

Lennox 59W40 Proving Switch 321702-401 the Bard 9043-411 is designedThe 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