York S1-024-35309-000 Pressure Switch

The York S1-024-35309-000 is an OEM-specified air pressure switch designed for combustion air proving in high-efficiency gas furnaces and packaged units. This furnace pressure switch features a SPNO (Single Pole Normally Open) contact configuration and is factory-calibrated to a set point of -.35 inches Water Column (WC). Engineered to monitor the differential pressure generated by the inducer motor, it ensures the combustion blower is drawing sufficient vacuum for safe ignition. As a direct HVAC pressure switch replacement, this component succeeds the MPL9300V0.35 and S1-2702-334P, maintaining administrative compliance with the original equipment manufacturer's airflow safety protocols. The "Close on Fall" operation means the contacts close when the negative pressure reaches the specified vacuum threshold, allowing the ignition control board to proceed with the sequence of operation. For technicians troubleshooting York furnace parts, this switch provides a reliable solution for persistent "pressure switch stuck open" codes when the inducer is operating within spec but the circuit fails to complete.

• Direct replacement for discontinued models MPL9300V0.35 and S1-2702-334P, ensuring proper physical fit and electrical terminal alignment.
• Precise -.35" WC set point prevents nuisance tripping while maintaining strict combustion safety standards.
• Durable diaphragm construction resists the corrosive effects of flue gas condensate frequently found in high-efficiency systems.
• Standard push-on terminal connections allow for rapid field installation during emergency service calls.

What is the set point for the York S1-024-35309-000?
This switch is calibrated to activate at -.35 inches WC (Water Column). It is essential to verify that the system creates a vacuum exceeding this rating for the switch to close successfully.

How does a "Close on Fall" pressure switch work in a furnace?
In a furnace application, "fall" refers to the drop in pressure (increase in vacuum) created by the inducer fan. When the vacuum reaches -.35" WC, the internal diaphragm shifts to close the electrical contacts, signaling the control board that combustion air is present.

Does the S1-024-35309-000 replace the MPL9300V0.35?
Yes, this part is the manufacturer-approved direct replacement for the MPL9300V0.35 and the S1-2702-334P, providing identical functional characteristics and mounting requirements.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.