high pitch noise in central heating system

[marshy]

our newcentral heating system is giving out a high pitch noise which is driving our son mad. Using a Glow Worm boiler , when we simply have hot water on there is no problem but when the central heating comes on there is a high pitch noise which is difficult to relate to any particular part of the system. The pump has a three speed setting and the noise is worse at setting 3. We think setting 2 gives less noise ,but is still there. Only on setting 1 does the noise vanish. We just have to sort this out before it drives us all crackers. Any help appreciated. Harry

 

[diesel_ltd]

if its a new system could just be air in the pump try bleeding it remember to top up the pressure in the system if it drops below 1 bar