water hammer after flushing toilet

[Matdio]

Hi, I have been having water hammer after flushing toilet in the past couple of weeks. I have tried turning off the stopcock and opened all taps to drain all the water in pipes and toilet. The water hummer then fixed for a few flushes but it comes back.

It's ok a few weeks ago before we fixed the bath tap which required to turn the stopcock off and back on. Or it is the problem with the push button flush unit needs replacing as it's 4 years old.

Thanks.

 

[nicam49]

Have you turned the stopcock on too far, so increasing the water pressure. Try turning it back a bit.

 

[Matdio]

Have you turned the stopcock on too far, so increasing the water pressure. Try turning it back a bit.

I haven't. I have only turned it on for around 2.5 cycles and I think it is not even half way

 

[Ric2013]

Stopcock fully on will increase flow but won't really affect the pressure. Common misconception, though.

By water hammer I assume you mean a loud hum as the cistern has nearly refilled? Or an actual bang?

 

[Matdio]

Stopcock fully on will increase flow but won't really affect the pressure. Common misconception, though.

By water hammer I assume you mean a loud hum as the cistern has nearly refilled? Or an actual bang?

There is banging / vibration noise from some of the pipes underneath the bath upstairs when the cistern has nearly or fully refilled. The toilet located near the bath.

 

[Ric2013]

What sort of fill valve is fitted to your toilet cistern?

I'm wondering whether either the fill valve doesn't like the fact that the water has been drained (sometimes dirt then gets into the nozzle and sometimes the slight vacuum in the pipes can inexplicably "upset" the valve, especially when the washer is a few years' old), or whether the difference is how the pipework under the bath is now sitting, possibly just slightly differently than it was before. I once lived in a house that had a noisy ballcock in the loft and the noise would disappear in you just applied a slight pressure to the (not properly supported) pipe feeding it. As it wasn't my house, a bit of string around the pipe and tied to a hook in a convenient rafter was my 'solution'.