The Armstrong Furnace R100811-05 is an L205F manual reset (M/R) limit switch engineered to protect Armstrong furnaces from dangerous overheating conditions. When the furnace plenum or heat exchanger reaches the rated high-limit temperature, this switch opens the control circuit and shuts down the burner — preventing equipment damage and potential safety hazards. Because it is a manual reset type, the switch must be deliberately reset by a qualified technician after a high-limit event, ensuring the root cause is identified and corrected before the system is returned to service.
Key Features
- OEM Armstrong Furnace replacement part — ensures proper fit and function
- L205F rating — opens circuit at 205°F to guard against overheating
- Manual reset (M/R) design — requires technician intervention after a trip event for added safety
- Direct drop-in replacement for compatible Armstrong furnace models
- Reliable bimetal sensing element for accurate, repeatable temperature response
- Helps maintain system safety and protects heat exchanger integrity
Application
- Designed for use in Armstrong Furnace systems requiring an L205F manual reset high-limit switch
- Suitable for residential and light commercial furnace applications
- Ideal for service replacement when the original limit switch has tripped, failed, or is damaged
Why Choose an OEM Limit Switch?
Using the correct OEM-specified limit switch ensures your furnace operates within its designed safety parameters. An improperly rated or aftermarket switch may not trip at the correct temperature, risking heat exchanger damage, carbon monoxide hazards, or voided equipment warranties. The Armstrong Furnace R100811-05 delivers the precise protection your system was built around.
