had a new worcester greenstar 25si/30si boiler fitted some 12 months ago and has been working fine .engineer came to serviceboiler last week and ever since boiler has been noisy when i say noisy i dont mean banging or clancking more like sound a fridge makes when running boiler is fitted inside a bedroom cupboard and has run very silent untill serviced.i sleep in adjacent bedroom and am awakend every morning when heating fires up as i said previouslyit is not overly loudbut i find it very annoying as before service boiler sounds were undetectable would be very gratefulfor any advice thanks