The Navien Tankless Water Heaters 30010238A Air Pressure Sensor 02-A is a precision monitoring component used in Navien condensing tankless water heaters. It detects and measures combustion airflow and vent pressure, sending real-time feedback to the control board to ensure proper combustion and safe operation. When balanced draft and venting are confirmed, the heater modulates burner... https://www.partshnc.com/30010238a-navien-tankless-water-heaters-aps-aps-02-a