What is a qr1c quick release valve and how do you troubleshoot it?

Answer 1

QR-1C valve takes air from the PP-1 or MV3 valve. That air goes through a line to the inlet of the QR-1C valve. As it does, it pushes down a diaphragm, which covers the exhaust port. Thus, the air is piped out of the outlet ports to the spring brake side of the brake chamber. When the air supply is removed, the diaphragm returns to an open state. This opens the exhaust port, and air from the spring brake chamber is evacuated out through it. If it's leaking air, if your brakes aren't releasing, if your brakes aren't setting when you pull the yellow brake control valve, or you get air exhausting steadily through the treadle valve with the brake control valve pressed, an issue exists.