My boiler is 7 years old up until 3 months ago it was going fine but then started to make a loud droning/winding noise which wakes me in the night. Noise is coming from boiler not pump. After CH clicks in just 1 minute afterwards the fan is quite audible, loudly whirring then decending then becoming loud again. I have had the fan replaced (costly) but to no avail! Noise is quite loud. Also, thermostat switches heat off, but fan can be heard whirring/clicking again. Any suggestions please.

Warwickshire lady, January 2012

When you change boiler do you power flush ,look like heat exchanger blocked,clean it out change pump,and install boiler protect device

ltd, January 2012