Caleffi’s 5350 Series AutoFill fast fill/pressure-reducing valve maintains system pressure at a set value, automatically feeding water as required when installed on the water inlet piping in closed hydronic systems. Because the valve is adjustable, the system pressure can be set to the appropriate pressure before the system filling phase and then will automatically shut off the water feed when the set pressure is achieved. A removable internal cartridge facilitates ease of inspection and maintenance. Available in 3/4” sweat or NPT union