Hello, we are sorry to hear about the issue you are experiencing with your SharkBite Pressure Regulator. The chatter or hammering is generally caused by low-flow high inlet pressure, where you have a high incoming pressure and are drawing a very low flow (flushing a toilet). It can also be caused by high-flow low inlet pressure where your inlet water pressure is close to the pressure setting of the valve and in high demand scenarios (taking a shower while running the dishwasher and washing machine together). We recommend that you adjust the pressure set up or down 1 full turn from the factory setting of 45 PSI. This usually fixes the issue. If you are still having trouble, please call our Customer Service Team at 1-877-700-4242 and we will be happy to help you with this issue and resolve it for you.