The BASO Gas Products H17CB-3 is a 3/8 inch pilot valve specifically designed for gas-fired HVAC equipment, most commonly furnaces and boilers. It's a small but critical component that controls the flow of gas to the main burner. Here's how it works: The pilot valve receives a signal, typically from a thermocouple or flame sensor, indicating the presence or absence of a pilot flame. ... https://www.partshnc.com/h17cb-3-baso-gas-products-38-pilot-vlv-wo-interrupter