hiya posted topic twice not much responce but hoping third time lucky. got a glowworm compact 80p combi doiler for ages whenethe ch is on been making a humming whirring sound only now and again though. had someone out to look at it they said it were a combination of fan and pump and said no problem could just b age and just started to make noise. but for the pst few days when the boiler not running ie; no heating on sometimes it makes a grating ringing noise for about 10 seconds then stops the a bit later on does it again and so on could this be related to the fan or pump replies very gratefull thanxs