The York S1-7680-3591 is an OEM auto-reset high-limit switch designed to protect York furnaces and heating equipment from dangerous overtemperature conditions. Designated as the L155-20F, this limit switch opens the circuit at 155°F and automatically resets once the temperature drops approximately 20°F to around 135°F — eliminating the need for manual intervention after a nuisance trip.
How It Works
The limit switch continuously monitors heat exchanger or plenum temperatures. If the sensed temperature rises to the 155°F trip point — due to restricted airflow, a dirty filter, or a blower malfunction — the switch opens, cutting power to the burner to prevent overheating and potential heat exchanger damage. Once conditions return to normal and the temperature falls back to the reset threshold, the switch automatically closes and restores normal furnace operation.
Key Features
- Auto-reset design — no manual reset required after temperature normalizes
- Opens (trips) at 155°F for reliable high-limit protection
- 20°F differential — resets at approximately 135°F
- OEM York replacement part — direct-fit for compatible York furnace models
- Helps prevent heat exchanger damage and equipment failure
- Critical safety component for residential and light commercial heating systems
Application
This limit switch is a direct OEM replacement for York furnaces and heating systems requiring the L155-20F specification. Always verify compatibility with your specific York model before installation. Consult the equipment service manual for proper mounting location and wiring procedures.
Specifications
- Brand: York
- Part Number: S1-7680-3591
- Model Designation: L155-20F
- Switch Type: Auto Reset High-Limit Switch
- Trip Temperature: 155°F
- Reset Differential: 20°F (resets at approximately 135°F)
- Reset Type: Automatic
