Water hammer

[Venger75]

Hi...I am a novice at DIY, the "i'll give it a go type"

I recently changed the washers in a kitchen hot water tap that was "vibrating/squealing"

The tap doesn't vibrate anymore but the pressure has dropped low and it struggles to kick in the boiler unless the tap is opened slowly. I have also now got water hammer that occurs when turning off any tap in the house quickly.

To try and remedy this I drained the pipes, and refilled the system, this seemed to have worsened the water hammer.

Next I am going to take off the hot tap again and give it a proper good clean out as I think this may be why the pressure is low on the kitchen as the bathroom is fine.

To try and get rid of the water hammer I was going to try and link the cold to the hot water using the washing machine outlets that are closest to the mains water inlet and try and force the air out.

My question is, if I do this will I risk causing damage to the pipe work or the central heating system?? I'm worried where the water is going to go as everything I have read has said to try this on a system that has a storage tank but I don't have a storage tank, it is mains fed. I'm worried if I try it I will end up with water shooting out of my walls.

My only other idea is to put extra clips on the pipework as well as gap foam to try and soundproof the pipes a bit.

I'd appreciate any answers or suggestions you may have, I need to get this sorted soon as the house is up for sale.

Cheers

 

[helpsy]

Linking the cold to the hot as you say you're going to try ,is what you do to try and force an air lock out with.
Water hammer is caused by shock waves when say a tap is closed quickly ( like 1/4 turn type)
You could try turning the main stop tap down a bit and see if this helps.
Are you running a combi or unvented system?

 

[Venger75]

I have a combi system.....I already turned down the mains valve but that had no real effect except to create more noise as the water squeezes through the smaller gap. I tried the same with the washing machine outlet as this is making the most noise because the washing machine valve closes so quickly, this did lower the effect of the water hammer but again the noise of the water squeezing through the valve has become very loud.

Should i not try to force the cold through the hot? I have read that this can temporarily solve the water hammer issue. I'm just worried about doing damage to any part of the system.

 

[helpsy]

You may need to make sure pipework is clipped.You can also get an item called a mini rester, which is for water hammer (how effective they are I don't know).I don't know if you could make one out of fittings and pipe, maybe some of the more experienced guys would be able to let you know.The mini rester is available from toolstation about £20.
Maybe a PRV?
Maybe isolation valves at items turned down a bit possibly.

 

[John Flower]

You need to ensure that all pipes are adequately clipped ,that all taps cannot be spun shut,and that all ballvalves are of the Bs1212 part 2 ,part 3 design . Also if your mains pressure is excessive you need to fit a pressure reducing valve to the incoming main and a mini shock arrester which is a mini pressure vessel.

 

[Venger75]

Hi guys,

Thanks for the replies....I solved the problem (albeit temporarily) by clipping all the pipes and closing the washing machine pipe slightly. The banging has stopped now

Thanks for your help.