We didn't use to get pipes knocking.
We run a Glow-worm Swiftflow combi boiler.
Suddenly now, when we turn the shower off (running off the combi boiler), we get a loud noise (maybe a knock).
Can anyone explain what may be the cause of this.
Thanks AD
If you have lots of water at high pressure travelling fast through a pipe and then stop it dead, it has nowhere to go and sends a shock wave through the system in an attempt to dissipate the energy. It solved by installing a "shock arrestor" near the offending tap/valve. In the olden days, a short stub of pipe was left, full of air for the same reason. A shock arrestor is more reliable and hygenic. It is basically a tiny miniature expansion vessel, (sometimes spring loaded instead of using a air pressurised diaphragm).
It may have got worse recently because pressure is greater, a pipe clip has given up the ghost (after physically preventing the knock for some years), or someone with a faster technique has started using the tap/valve. A particular cause of new knocks is the installation of quarter turn taps/valves, which close much faster than a twist your arm off type.
Christian.
You might have a washer going bad in the shower valve. If this just started and nothing has changed then look to the valve first. Does it happen when you turn off sink etc..?
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.