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I've just started hearing a regular thud/knocking sound somewhere in my house. It's too metronomic to be animals/humans doing whatever - should I call a plumber? It's really hard to locate and seems to move. It's not 24/7 either.
Dodgy plumbing? (First time in several years Ive experienced this).
Walls expanding/contracting in this hear (previous owners had insulation piped in).
Ghost?
[url= http://singletrackmag.com/forum/topic/my-daughter-sees-ghosts ]Did you see a paint tin?[/url]
Mine does this after I flush the toilet once the cistern fills up. I guess its loose pipes or something knocking when the pressure increases when the water turns off.
Mine does this after I flush the toilet once the cistern fills up. I guess its loose pipes or something knocking when the pressure increases when the water turns off.
That's water hammer (or surge, or may other names), basically the water in the pipe has momentum, so when the valve closes suddenly it hits the valve with a thud as the energy is dissipated. On long pipes it can be quite a lot of energy so things like unsupported corners get a bit of a jolt.
So it could possibly be a tank in the loft or a cistern opening and closing (and if its at random rather than a short time after you've used water elsewhere it means something somewhere is leaking).
Ours does this every night and every morning. We reckon it's something to do with the boiler. We found the boiler is doing something and when it stops there's a thud. Maybe it's the pressure moving pipes?
Just had this; it took me a few maddening weeks to solve the mystery. I went and sat by the water meter and could see that water was flowing very slowly prior to the thump so I knew something was leaking. Went to the attic and fiddled with the ballcocks (ooh Matron!) but couldn't reproduce the sound. Our downstairs bog has a Geberit concealed cistern, which overflows into the bowl not out of the house. The knock seemed to be coming from there but I couldn't see water until I held a piece of bog paper against the back of the pan and it got wet; the trickle of water was invisible in the bright light. The water level was dropping and the fill valve opening momentarily then closing with a chuff and a thump.
I removed the flush mechanism, which is easy with a Geberit cistern and found that the soft polymer washer that holds back the flush had water blisters in it; Googling confirmed that this is common and the temporary cure is to prick the blisters with a pin. New washer and problem solved.
Ours does this every night and every morning. We reckon it's something to do with the boiler. We found the boiler is doing something and when it stops there's a thud. Maybe it's the pressure moving pipes?
It's the motorised valve that controls your hot water or your heating; the synchronous motor moves an arm, which moves a hard rubber ball to close the port, sometimes causing water hammer. Our Y plan valve was doing it so I replaced it and the noise was no better so I wrote to Honeywell, who replied with a long rambling explanation that if you don't install the valve with a minimum of six inches of straight pipework each side of it, laminar flow in the water coming from a bend in the pipe has been found to cause the thump. So that was me told, then.
That makes sense! My dad helped install it many moons ago.
It got worse when we go a new boiler a few years ago. Presumably because it was more powerful it became worse.