Water Hammer - Help Please

[Wurzel83]

Evening all

I bought a 1929 house 6 months ago which I am starting to renovate. As far as I can tell there is a 15mm copper pipe comming in from the road to the stop cock chamber in the front garden and then goes off in the direction of the house where somewhere it joins old lead pipe work. At the kitchen and bathroom the lead pipe terminates and is joined to 15mm copper again.

I have replaced the kitchen (moved washing machine by 2m and sink by 1m) and used new 15mm copper pipe and compression joints to do this. I also fitted a stop cock under the kitchen sink so I can turn off the supply to the tap, outside tap and washing machine. I have secured the pipe to the wall in several places. I have not touched any other mains plumbing in the house.

After completing the kitchen I turned on the outside stopcock again and opened it fully forgetting to note the no. of turns when I turned it off. Since then we had pipe hammer when turning off taps suddenly. We also had a thudding noise comming from the electric shower and washing machine when the flow was turned off. In addition we had spontanious resonating comming from the lead pipe which goes up into the Bathroom which would just continue rattling away until you turned on the Bathroom tap.

On the wekend, I turned the stopcock in the off in the front garden. I opened up the one in the kitchen completely and turned the one in the garden on so that there was just enough pressure to power the shower and kitchen tap at the same time. All was good - no tap hammer, resonance or noice from shower/washer.

Today however, the hammering has come back! When the washing machine changes its cycle, you do not get the thud from the valve in the machine but you do get hammer under the worktops and also under the floor in the hall where the lead pipe splits to go up to the Bathroom and over to the kitchen on the other side of the house. Resonance associated with the Bathroom tap has not come back. The shower is the same as the washer - no thud from the valve but hammer going down the lead pipe into the hall (where the pipe goes out into the front garden).

In good time I will replace the lead pipe for copper. What can I do in the mean time? Water hammer Arrestors? Vents? Air traps? Pressure or Flow reducing valve on main supply?

Any advice will be much appreciated.

Thanks

Rob

 

[Nige F]

PRValve on main supply

 

[Wurzel83]

Thanks.

Can you fit these to a lead pipe?

 

[Wurzel83]

I pulled up the floor boards in the hall today and found a lead pipe comming in from the front garden. There is a small gap in the bricks where the Gas and Water mains come in - it is at this point where the pipe splits for the bathroom and kitchen. You can not get a fingure in there, never mind a spanner. I therefore can not see how I can get a PRV on the main supply without digging up the front garden and door step to fit a new copper pipe through to the house.

Is it acceptable to put a PRV in the kitchen and bathroom where there is 15mm copper pipe? Would it be worth fitting Water Hammer Arrestors to the taps and appliances which cause the Hammering? Am I right to assume that a PRV does something other than restricting the flow rate like turning down the primary stop cock does?

Cheers

 

[Fluffster]

An pressure regulating valve does not alter your flow it controls the pressure rate pushing your water into the house.

A shock arrestor basically accomodates the sudden pressure changes when opening and closing outlets. Solenoid valves on washing machines are notorious for this.

You may even get away with fitting an arrestor just past your stop valve in the kitchen.

Pete