The Sterling HVAC 11J11R06778-003 Pressure Switch is a safety control component designed to monitor air pressure within HVAC systems and ensure proper operating conditions before allowing the equipment to run. It works by detecting pressure changes and opening or closing its electrical contacts when the required airflow or venting pressure is achieved. Commonly used in Sterling furnac... https://www.partshnc.com/11j11r06778-003-sterling-hvac-pressure-switch