Lennox 98M86 Rollout Switch

The Lennox 98M86 Rollout Switch is a critical furnace safety limit designed to monitor burner temperatures and prevent hazardous flame rollout conditions. This thermal rollout switch features a 350 degrees F actuation point with a manual reset mechanism, ensuring that a technician must inspect the combustion area for heat exchanger breaches or venting issues before the system becomes operational again. As a Single Pole Single Throw (SPST) component, it provides reliable circuit interruption the moment out-of-sequence heat is detected near the burner box.

This OEM Lennox part is the direct updated version for legacy part numbers 98M8601 and R37520B004, as well as R37520B015. It is commonly utilized across Lennox, Armstrong, and AirEase furnace platforms. Featuring 90-degree quick-connect terminals, the 98M86 is engineered for a seamless drop-in fit during HVAC repair and emergency service calls. For veteran contractors, this switch is the standard solution for resolving "Rollout Switch Open" diagnostic codes (often 8 flashes on Lennox boards) caused by improper gas pressure, blocked flues, or restricted heat exchangers.

• Precise Thermal Protection: Factory-calibrated to actuate at 350°F (+/- 18°F) to protect the cabinet and internal components from heat damage.
• Universal Compatibility: Serves as the primary replacement rollout switch for multiple Lennox-family brands, streamlining your truck stock.
• Enhanced Safety Logic: The manual reset design prevents automatic cycling of the system under unsafe firing conditions, forcing an onsite safety audit.
• Durable Construction: Built to withstand the high-heat environment of the burner assembly with robust terminal connections.

What causes this switch to trip repeatedly?
Frequent tripping is rarely a fault of the Lennox 98M86 itself. It typically indicates a cracked heat exchanger, high manifold gas pressure, or a restricted chimney/vent pipe that is forcing flames to "roll out" toward the switch.

Can I bypass the manual reset if the button pops?
No. In professional HVAC practice, bypassing a 350F rollout switch is a significant safety violation. If the switch has tripped, the combustion process is compromised and requires a full inspection of the heat exchanger and draft inducer performance.

How do I confirm compatibility with my specific furnace?
This 98M86 switch is the direct successor to 98M8601 and R37520B004. Verify your existing part's temperature stamp; if it matches 350F and uses an SPST manual reset configuration, this is the correct technical replacement.

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.