This adjustable water pressure regulator is meant to be installed before the jacket inlet (or before Temperature Control Valve) as an added safety measure to prevent water pressure in the fermenter and Boil Kettle jackets from going over 5psi.
Ensure that the flow of water is always in the direction of the arrow stamped on the side of the regulator. Care should still be taken to ensure that flow out of the jacket is not restricted in any way and that quality kink-resistant hoses are used to ensure pressure does not build up in the jacket. The screw on top needs to be rotated until the regulator only permits 5psi (7psi in the 4-in-1s) of water. Some assembly may be required.
Warning: always ensure water is flowing in the same direction as the arrow stamped on the side of the regulator. Temperature range for this regulator is .6°C/33°F – 60°C/140°F. The pressure gauge might not read anything unless there is back pressure (see link below for details).