What is causing the noise in my Potterton Suprima 40 gas boiler?
My Potterton Suprima 40 gas boiler began to make a loud whirring noise shortly after it came on this evening. We turned it off and restarted it only for the noise to start again after 5 mins or so. We have now switched the boiler off and have engineer arranged for tomorrow. Any ideas what it could be?