Help !!! Pipe in bathroom banging...Driving me mad....

[Davy007]

After investigation behind the sink / end of bath panel I have discovered that the pipe from the sink (small white) runs away and meets with a large grey pipe were the water then falls down and away. All the pipes are insulated so i have held each one to see if it bangs ? No ! The white pipe from the sink got hot with the hot water passing thru but the banging is persistant and loud. By mistake i put pressure on the big grey pipe which is 2 inches off the floor and the banging stopped !!! With this in mind i kept the hot water running and occasionally pressed this big grey pipe and again the banging stopped. This pipe ran from past the sink to the far corner wall.

Now the big grey pipe is the toilet outlet so i cannot understand why this pipe is making so much noise when the hot water is running thru a different pipe. The only time they come together is away in the corner when all the water / waste falls to the ground !!

If any body can shed any light on this i would be most grateful.

I have already consulted an engineer from a major gas/electric supplier who came to service all my heating and plumbing and i was told that i just had to live with it, nothing could be done !

Any further help assistance or advise would be so gratefully received.

Thanks a million in advance.................

 

[Nige F]

Grey pipe is a soil pipe and the banging is the expansion+contraction of the plastic where the pipe is binding against something...probably timber....bloody chippies cut things in tighter than a....... I see where you are from/ Major engineer....... Look for my comments about gas fitters too