The 5350 series AutoFill™ automatic filling valve is a pressure reducing valve which when installed on the water inlet piping in closed hydronic systems will maintain system pressure at a set value, automatically filling up with water as required. Fast fills the system to set pressure then automatically shuts off the water feed. This product is factory pre-set to 15 psi system pressure. To adjust the set pressure, simply turn the adjustment knob while observing the integral downstream pressure gauge. This product has the characteristic of being pre-adjustable, which means that it can be adjusted at the right pressure value before the system charging phase. After installation, the system pressure will automatically adjust itself to the set value and the water feed will stop when the set pressure is reached. The internal cartridge containing all the controlling components is preassembled as a self-contained unit, to facilitate inspection and maintenance procedures.