Hi,
The problem I have is that sometimes when the central heating is on I get a noise that sounds somewhat like a dive bombing aircraft. By that it seems to start steadily and then increase in loudness. It doesn't seem to happen all the time though. The noise is the the flow and return pipes close to the boiler but nowhere else in the property. My assumption is that it might be caused by air in the system but I've bled all the radiators and they seem fine. I also found a bleed valve in the attic and this seems to be free of air too. The system is a fairly old pumped vented one. the property is a bungalow so there isn't a lot of head between the tank and the pump which is installed in the roof space. There is also a divertor valve in the roof for the hot water. My thoughts as to the source of the noise are as follows but I'd like to know if there is anything else more obvious:
Sludge in the pipe work (the water is a brown colour and smells of inhibitor)
Aeration from the pump - It's on position 2 at the moment
I can email pictures of the system if that helps.
The problem I have is that sometimes when the central heating is on I get a noise that sounds somewhat like a dive bombing aircraft. By that it seems to start steadily and then increase in loudness. It doesn't seem to happen all the time though. The noise is the the flow and return pipes close to the boiler but nowhere else in the property. My assumption is that it might be caused by air in the system but I've bled all the radiators and they seem fine. I also found a bleed valve in the attic and this seems to be free of air too. The system is a fairly old pumped vented one. the property is a bungalow so there isn't a lot of head between the tank and the pump which is installed in the roof space. There is also a divertor valve in the roof for the hot water. My thoughts as to the source of the noise are as follows but I'd like to know if there is anything else more obvious:
Sludge in the pipe work (the water is a brown colour and smells of inhibitor)
Aeration from the pump - It's on position 2 at the moment
I can email pictures of the system if that helps.