water noise

[huw53]

Hi, I've installed my Evohome and everything works fine. However, I've noticed in two of the radiators since the installation a lot of water noise. I have a Worcester greenstar regular boiler with a copper cylinder two motorised vales one hot water and one heating. The system has one of these bypass valves which was set by the installer some time back. My pump is a grundfoss and I've looked at the instructions it mentions about changing the pump has three fixed speeds ( its one 1 now) and three proportional pressure curves. Should I change it over to proportional pressure curve ? is that suitable for a green star boiler. Before someone asks I've tried rebalancing the system using the pock shield valves. The only way at the moment that I can reduce the water noise is by dropping the them on the radiator valve.

[Richard]

Certainly sounds like high Delta P over the valve seat... The bypass valve may not be set correctly as the pump speed is dependant on the required flow rate and the head pressure required to get the water around the heating system.