I have a Biasi boiler model M296.245M/C. When I switch heating on my boiler flares but I can hear water rushing through boiler. This lasts a few minutes and no heat getting to radiators. However when I turn on hot water tap I get hot water & then when switch tap off the radiators start to heat up. Pressure is fine. Boiler is 3 yrs old.
Any advice would be great.
Thanks