Our C/Heating system is driven by a Worcester/Bosch Highflow 4.5 combi.
We are experiencing loud vibration noise like a pneumatic drill in the pipes which is cured by slightly altering the thermostat on one of the downstairs radiators. This can happen several times in an evening when its on.
I have bled the radiators today and there was a lot of air in the system; I did allow more water into the c/h system several times by opening the valve at the boiler before bleeding the next radiator. The noise still occurs. Is there anything else I can do or should I call in a Pro? Thanks