Knocking in pipes - stops when stopcock off

[tuloula]

Hi there - I have an issue with my pipes that I am hoping someone can advise on (even if it's just to tell me to call out a plumber!).

I can hear a knocking noise in my pipes, in particular in the area near the boiler and in the bathroom. It persists when the boiler is turned off (even when I turn it off at the wall) so I am pretty sure it's not boiler related. It only stops when I completely cut off the water supply by turning off the stopcock. But it starts up again as soon as I turn the water supply back on.

I read some advice online to turn off the water supply, empty the pipes and turn it on again - but that doesn't seem to have any effect. I have also bled the radiators to no effect.

Any thoughts about other steps I can take myself before I call someone out?

In case it's relevant: house was built in the 70s and I have a Potterton combi-boiler.

Thanks

Louise

 

[Best]

First check if there are any ball valves on toilet cisterns (or any other places ) as they can cause knocking noise.
Often simply a new washer fitted to ball valve will fix, but a modern fill valve, like Fluidmaster Pro brass tailed valve on bottom connection cisterns would work well on mains pressure

 

[king of pipes]

The first thing to check is your stopcock if its the loose jumper type then this could be your problem as above check all ballvalves even ones not easily visable inside toilets ect , and the securing of your pipework , best of luck kop