Water hammer from unvented cylinder

[Madrab]

- it's hard to do because the shock is so strong you can hear/feel it on the inlet pipe

Wouldn't matter - if you are in the right location you will hear the difference, use that method all the time to locate a problem valve anywhere on a pipe run

 

[Taconite5]

Wouldn't matter - if you are in the right location you will hear the difference, use that method all the time to locate a problem valve anywhere on a pipe run

I'll give it another go!!

 

[Madrab]

If you hold it onto the pipe say a metre or 2 away and then at the valve there should be a noticeable difference.

 

[Johntheo5]

This water hammer/pressure spikes is a bit of a mystery to me.

I have a washing machine with a 10M, 15mm (12.5mm ID) pipe run from the mains which has a DCV (double check valve) where I installed a PG today very near the DCV to take a few readings. The filling rate is a measured 8LPM and when the solenoid valve closes after filling, the PG rises from its dynamic pressure of 2.2bar to 2.7bar which is only 0.4bar above its normal static pressure of 2.3bar. Using the attached formula this means that the solenoid valve is taking 1.4 secs to close, I read that a solenoid valve will normally close in 50 millisecs, 0.05secs, if so then the pressure spike should be in the order of 11.3bar? PG ~ 13/13.5bar but I'm not getting anything remotely approaching this, maybe the flexible w/machine flexible hose is taking up the spike?. You can do your own calcs, if interested.

Water Hammer

Rapidly closing or opening valves - or starting stopping pumps - may cause pressure transients in pipelines known as surge or water hammer.

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