Review on Pfister 9740420: High-Performance Pressure Balanced Valve Cartridge Sub Assembly by Chris Nonamaker

Hard water shortens the life of these valves. This is the second one I've replaced, no problem. Here's what I did to replace it: 1) Shut off the water to the house. 2) Before disassembling the flow control valve, turn it on to release the residual pressure. 3) Replace the defective unit with a new one. last thought Be sure to inspect the valve body before inserting the new valve assembly. I have noticed that the old o-rings are sticking to the inside of the case. Use needle nose pliers to easily remove them.