Lennox 15M45 Rollout Switch

As a veteran tech, you know that a tripped rollout switch isn’t the problem—it’s the symptom. The Lennox 15M45 Rollout Switch is a critical safety component designed to break the circuit when it detects flame rollout or excessive heat buildup near the burner box. This genuine OEM replacement is calibrated to actuate at 200°F, featuring a manual reset button that forces a physical inspection before the system can be fired back up. This switch is a direct, identical replacement for the Lennox 15M4501 and is commonly found in G26 and G32 series furnaces, as well as various Allied, Armstrong, and Ducane units. With its SPST (Single Pole Single Throw), normally closed configuration, it provides a dependable 24V signal interrupt to the integrated furnace control if combustion gases aren't drafting properly through the heat exchanger. When you're dealing with "Rollout Switch Open" codes or 8-flash diagnostics on a Lennox board, this high-quality HVAC safety switch ensures the equipment stays down until you've cleared the flue or addressed the heat exchanger integrity.

• Direct OEM Compatibility: Engineered specifically for Lennox heating equipment; replaces part numbers 15M4501, 26H7601, and 26H76.
• Precise Thermal Response: Fixed 200 degree F trip point (typically +/- 12°F) ensures shutoff before high-limit conditions cause cabinet damage.
• Manual Safety Lockout: The manual reset rollout switch design prevents the furnace from auto-cycling, protecting the heat exchanger from repeated thermal stress.
• Standardized Electrical Hookup: Features standard 1/4" spade terminals for a quick, secure connection in high-vibration burner environments.
• Green ID Color Code: Simplifies field identification for technicians matching specifications on multi-switch manifolds.

What causes this rollout switch to trip repeatedly?
Usually, a trip indicates poor drafting, a blocked flue, or a compromised heat exchanger. If the inducer isn't pulling enough or the secondary heat exchanger is restricted, the flames will "roll out" toward the switch. Always check gas pressure and venting before assuming the switch is faulty.

Can I test the 15M45 switch with a multimeter?
Yes. With the power off and wires disconnected, check for continuity across the terminals. If the reset button is pressed in but you have no continuity, the internal bimetal disc has failed and the unit needs replacement.

Is the 15M45 interchangeable with the 15M4501 model?
Yes, they are technically identical. The 15M45 is the current professional service part number and maintains the exact same 200°F thermal profile and SPST configuration.

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.