If I don't sort this water hammer my weddings off!!

[smudger]

Hiya Folks. Hope you are all well. I have a problem with water hammer and can't shift it (it's in my house so its taken me ages to get round to it!). We recently had a wetroom fitted downstairs and since then we have had quite bad water hammer when running the hot tap (bath mainly). We have a combination immersion cylinder and occurs when refills. Cold pressure is quite high. I thought it was air trapped as elbow into ballvalve seemed to be >90 deg and its worse as ballvalve starts to shut off and restricts flow. I replaced this section with a pipe bend rather than elbow and checked pipework properly clipped. Also replaced washers etc in valve and checked correct insert. Then I drained down and refilled. All seemed ok. Been down in Devon looking after mom for a while but my partner says that it has returned as before. I think my options are to check hot pipes between heater and bath (under floor so will be a pain), replace ball valve (just in case), fit something (Venturi?) to reduce water pressure as quite high, a dampener, or one of those little T pieces. I didn't fully drain down cold water system only hot as problem only occurs when the cylinder refills. Asked locally but no closer to solution so I come to ask you guys (and gals) as always get good info in here.

 

[glenno1]

Fit new ball valve 1st call id say

 

[Killy Bing]

How high is the pressure? Pressure reducer on the incoming mains if its excessive

 

[smudger]

Like your thinking Glenno, easiest option first! Thanks for responding so quickly.

 

[smudger]

How high is the pressure? Pressure reducer on the incoming mains if its excessive

Not sure exactly, probably good idea to find out though. Will do that drackly.

 

[smudger]

How high is the pressure? Pressure reducer on the incoming mains if its excessive

Just checked pressure on kitchen tap and showing just under 6.5 Bar. Probably a bit higher than needed, eh? Especially as live in small 2 bed cottage.

 

[Killy Bing]

Ohhh i would certainly say so! 2 bar would be enough for your house 3 if you want more ooomphh at the kitchin tap!

would explain why the washers weren't lasting too!

 

[smudger]

Off to plumbers merchant then, would you recommend any particular type? Never fitted one but assume I fit it after the internal stopcock.

 

[dancinplumba]

Just checked pressure on kitchen tap and showing just under 6.5 Bar. Probably a bit higher than needed, eh? Especially as live in small 2 bed cottage.

Static or dynamic ? 6.5 static is fine

 

[thompsonbrown]

Try turning your cold mains stopcock down.

 

[dancinplumba]

If you install pressure reducing valve you will also need expansion vessel

 

[dancinplumba]

Try turning your cold mains stopcock down.

Only reduces the flow rate not the pressure

 

[thompsonbrown]

Only reduces the flow rate not the pressure

Restricting incomming mains supply will reduce water pressure to ball valve when filling tank,
But your right, will not reduce static pressure of mains supply.
As water hammer has only started since new wetroom was installed, then theres a chance that stopcock was cracked down before install and left fully open after.

 

[Killy Bing]

If you install pressure reducing valve you will also need expansion vessel

Im intregued, its unlikely the mains would expand enough to warrent an expansion vessel, or am i being really inexperianced here?

 

[stevetheplumber]

Im intregued, its unlikely the mains would expand enough to warrent an expansion vessel, or am i being really inexperianced here?

im not sure about that either explain please dancin?

 

[dancinplumba]

Cold water entering a property picks up heat from property which causes it to expand therefore pressure increases, this can cause water hammer and fitting damage. if prv installed this expansion cannot go back down mains and is therefore taken up by expansion vessel

 

[dancinplumba]

Restricting incomming mains supply will reduce water pressure to ball valve when filling tank,
But your right, will not reduce static pressure of mains supply.
As water hammer has only started since new wetroom was installed, then theres a chance that stopcock was cracked down before install and left fully open after.

Restricting incoming supply will not reduce pressure to ball valve at all