Description
The York S1-024-35888-000 A/R Limit Switch reads heat exchanger plenum temperature within gas-fired furnaces, holding its normally closed contact in the burner control circuit until the plenum temperature reaches 235F. At that threshold the bimetal sensing element flexes to open the contact, interrupting power to the gas valve and shutting down the burner to stop further heat accumulation in HVAC systems. The 30-degree differential between the open and closed points means the contact remains open until the plenum drops back to 205F at which point the element returns to its closed position and restores the circuit without direct activation.
