Pam asked ... Do I need to open the housing to dry the motor?    |    James asked ... Remove enterprise enrolment from an Asus Chromebook C523N?    |    tom schwartz asked ... Bosch maxx 6?    |    Noman asked ... Reverse light switch?    |    Suzie asked ... Stuck Feed dog?    |    Click here to ask your question

valliant tubomax gb 820 noise?

boiler is making high pitch noise when central heating on. The noise stops as long as the hot water tap is on.Noise goes off when the boiler is switched off and also when central heating is off.
What is the proble? How to mend it?
S Chatterjee, August 2009