Strange issue with plumbing

agile83

Hi guys,

Having a strange issue when showering in our main bathroom. Basically we have a shower pump in the airing cupboard. This powers the ensuite shower and family bathroom shower. When I use the ensuite shower there is no issue, however using the main bathroom shower for over 5 to 6 minutes, there is a sort of banging / throbbing noise every second or so coming from the cold water pipes. If you turn a cold tap on when this noise is happening the water comes out but every second in time with the noise it is like someone squeezing the pipe so less water comes out. You can feel the vibrations on most cold water pipes around the house too. The hot water flow and pipes are not affected at all.

As soon as you stop the shower the noise fades quieter and quieter until it stops completely about 10 seconds later. It seems to me like the water supply is kind of catching up with the demand or something.

Any ideas what this could be and / or are there any tests I could do to get more clues as to what might be causing this? We recently moved in to this house in June and shortly after I changed the shower head for a Mira Eco shower head, but annoyingly I dont know if this problem was happening before and also I binned the original shower heads so I cant test it unless i buy a new one!

macman

The pump is causing a vibration through the system on the cold side on the main bathroom shower? Run the shower and see what is happening to the cold supply pipe at the pump, or where it divides to feed the two showers.

agile83

cheers for the prompt response Macman, what do you mean when you say run the shower and see what is happening? Do you mean open the airing cupboard and feel the pipes etc to see where the noise is coming from? I did that tonight when my wife was in the shower but couldnt detect where or what was causing the issue.

Any further pointers much appreciated, cheers

southcoastrgi

take off the new shower head & run the shower with just the hose connected for the normal amount of time it takes for the noise to appear if it's ok then you know its the new shower head, or swap the heads over between the showers & again do the test

Mr_Ted

agile83 wrote: »

there is a sort of banging / throbbing noise every second or so coming from the cold water pipes. If you turn a cold tap on when this noise is happening the water comes out but every second in time with the noise it is like someone squeezing the pipe so less water comes out. You can feel the vibrations on most cold water pipes around the house too. The hot water flow and pipes are not affected at all.
As soon as you stop the shower the noise fades quieter and quieter until it stops completely about 10 seconds later. It seems to me like the water supply is kind of catching up with the demand or something.

This would indicate that it is water hammer, the jumper in the stopcock is for some reason moving up and down in its housing rapidly and therefore momentarily shuts of the flow and then goes back to full flow, and I'm guessing, but is it possible that the new shower head has a setting at which the flow pulses?

agile83

Hi Mr Ted, interesting you mention about the pulsing shower head, i am sure I read something about this when googling the Mira Eco showerhead, I will google it again tomorrow and will definately try taking the showerhead off and running it.

Would the banging of the pipes or whatever it is cause longterm damage do you think?

ValHaller

agile83 wrote: »

Would the banging of the pipes or whatever it is cause longterm damage do you think?

Yes. It could see off soldered joints. I have seen off a soldered joint with one very extreme instance of water hammer.