Description
York S1-3500-3121 AUTO Limit Switch Overview
The York S1-3500-3121 is an OEM-replacement automatic (AUTO) limit switch designed for use in York heating systems. With a temperature operating range of 105°F to 165°F, this limit switch provides reliable high-temperature protection by shutting down the burner when the heat exchanger reaches unsafe temperatures — then automatically resetting once conditions return to normal.
Key Features
- Temperature range: 105°F – 165°F
- AUTO reset operation — automatically resets after temperature drops to safe level
- OEM York replacement part (SKU: S1-3500-3121)
- Designed to protect furnace heat exchangers from overheating
- Direct drop-in replacement for compatible York furnace models
How It Works
The limit switch monitors the temperature inside the furnace plenum or heat exchanger. If the temperature exceeds the set point (165°F), the switch opens and interrupts the burner circuit to prevent damage or fire hazard. With AUTO reset functionality, the switch automatically closes and restores normal operation once the temperature falls back to a safe level — no manual intervention required.
Application
- York residential and light commercial furnaces
- Replacement for worn, failed, or tripping limit switches
- Suitable for HVAC technicians performing OEM-spec repairs
Why Choose OEM York Parts?
Using genuine York OEM replacement components ensures proper fit, function, and system reliability. The S1-3500-3121 is engineered to meet the original equipment specifications, helping to maintain warranty compliance and extend the service life of your York heating system.
