Armstrong / Ducane Limit Switch 36W90

Armstrong / Ducane / Lennox 36W90 Furnace High Limit Switch | 160-190°F, 3" Insert

Maintain strict operational safety and prevent heat exchanger damage with the genuine Armstrong / Ducane / Lennox 36W90 Furnace Limit Switch. This premium Factory Authorized Part is a critical electronic safety component engineered specifically for residential gas furnaces under the Lennox family of brands, including Armstrong Air, Ducane, and Allied Air. Designed with a 3-inch insertion probe, this switch mounts directly into the furnace vestibule to monitor internal heat exchanger temperatures, instantly cutting power to the gas valve if temperatures spike past safe operating limits.

Featuring an automatic reset design, the 36W90 operates within a factory-calibrated 160 to 190 degree Fahrenheit thermal window, reopening the gas circuit automatically once the system cools down to normal thresholds.

Technical Specifications:

• Model/Part Number: 36W90
• Switch Type: High Limit Safety Switch
• Temperature Profile: 160°F to 190°F Limit Range
• Insertion Depth: 3-Inch Insert Probe
• Reset Configuration: Automatic Reset
• Voltage Compatibility: 24 VAC Control Circuits
• Application: Residential Gas-Fired Furnaces

Key Features & Benefits:

• Genuine OEM Factory Quality: This is a brand new, authentic factory-certified component—not an aftermarket substitute. Built to enforce the exact structural safety tolerances and timing thresholds specified by original Lennox and Armstrong engineers.
• Proactive Overheat Protection: Safeguards your primary heat exchanger against structural cracking, warping, and premature fatigue by breaking the 24V safety loop the moment system temperatures hit dangerous levels.
• Direct Mechanical Drop-In: Features the original factory bracket footprint and standard male spade terminals, allowing technicians to pull a faulty limit switch and complete a replacement in minutes without modifying the furnace cabinet.

Why Buy From Shortys HVAC Supplies?

At Shortys HVAC, we deal exclusively in Original Equipment Manufacturer (OEM) components because there is absolutely no room for compromise when repairing furnace safety loops. Installing a genuine Lennox 36W90 Switch ensures your heating asset maintains its original ANSI safety ratings, fuel efficiency profiles, and active manufacturer warranty lines.

Shipping Information: We provide fast, competitive shipping rates across the continental United States, delivering critical electrical safety parts straight to your shop or doorstep to quickly eliminate system down-time.