I have moved into a new house that has a typical gravity central heating system.
When it's calling for CH the boiler and the pipes around the pump area are very noisy - hissing, spluttering and turbulance in the pipes. No banging though! The noise continues for 30 seconds or so then dies down but comes back after a minute or so. This continues in various degrees of severity untill the stat cuts the pump off.
When in hot water only mode and with the boiler fired up the system is silent so it's only when the pump is on.
I did an experiment and ran the pump with no heat in the boiler and it was also silent. I've bled all the radiators and the pump but no air was present.
Has anyone any idea as to the cause and how to cure it? Could it simply be sludge in the system or is the pump too slow or fast? Pump is a Willow Gold set on speed 2 and boiler is a Baxi something - about 20 yrs old.
When it's calling for CH the boiler and the pipes around the pump area are very noisy - hissing, spluttering and turbulance in the pipes. No banging though! The noise continues for 30 seconds or so then dies down but comes back after a minute or so. This continues in various degrees of severity untill the stat cuts the pump off.
When in hot water only mode and with the boiler fired up the system is silent so it's only when the pump is on.
I did an experiment and ran the pump with no heat in the boiler and it was also silent. I've bled all the radiators and the pump but no air was present.
Has anyone any idea as to the cause and how to cure it? Could it simply be sludge in the system or is the pump too slow or fast? Pump is a Willow Gold set on speed 2 and boiler is a Baxi something - about 20 yrs old.
