Hi,I have got a Worcester 28i boiler.I have just noticed that the pump will run for approx 5-10 miutes sometimes every morning at eight o,clock sometimes not .I can hear water ciculating round the system.This happens with the central heating controls switched to off and when it happens none of the lights on the boiler come on,also the boiler does not fire up.While the weather is warm I only draw hot water from the boiler with CH turned off.I have read the manuals that came with the boiler and cannot find anything relating to why this is happening.The boiler is approx 5 years old.Is this normal for this boiler?.regards