A PRV is a Pressure Reducing Valve that is commonly placed on water distribution systems and within individual homes, multi-family homes and businesses. There are two types of water pressure reducing valves, direct acting and pilot operated. Both use globe or angle style bodies. Valves used on smaller piping diameter units are cast from brass; larger piping diameter units are made from ductile iron. Direct acting valves, the more popular type of a water pressure reducing valves, consist of globe-type bodies with a spring-loaded, heat-resistant diaphragm connected to the outlet of the valve that acts upon a spring. This spring holds a pre-set tension on the valve seat installed with a pressure equalizing mechanism for precise water pressure control.
Let me ask YOU a question. Have you noticed anything different going on when using your plumbing items (faucets, shower/tub, hose bib, etc.)? Well this might be a symptom to your PRV. Is the water too harsh, is the pressure on it too high? Or have you noticed that the food on the dishes just doesn't come off as easy or that showerhead isn't spraying as hard as it once did. This is generally the first thing you notice and if you are like me you won't think too hard about it until the next thing happens.
Both a screaming noise and a knocking noise are signs of high water pressure. The typical inlet water pressure to a home is about 40 to 45 psi. Normally, it should not exceed 60 psi. The pressure regulator is usually preset to 50 psi. However, it can be adjusted anywhere from 25 to 75 psi. Or in some cases it may need to be replaced because it won’t adjust and/or leaking.