Effective "Water Hammer Arrester"??

RickDelta

Hello HeatingHelp.com community! : )

I would want protect a prototype water filter design from exposure to "water hammer".

The filters are exposed to many quick closing solenoid valves throughout the commercial building.

Instead of using a standard "hammer arrester" , my question is, if I had an existing

conventional "water expansion tank" in the system already, wouldn't that serve just as well an arrester as well?

….. thoughts on this?

Thanks!

tcassano87

In my opinion, no it won’t, they serve two different purposes, Hammer Arrestor is specifically for quick closing valves and that extreme shock.
No different then having an expansion tank doesn’t prevent you from needing hammer arrestors on a laundry box

kcopp

Potable water expansion tanks are not designed to do that….that being said I have used them for that application before.

jesmed1

https://forum.heatinghelp.com/discussion/200833/effective-water-hammer-arrester

Think of the water hammer as a shock wave that travels at the speed of sound from the closing valve upstream through the piping system. Depending on where the valve is, the shock wave could reach your water filter before it reaches the expansion tank. It's like saying you have a bulletproof vest, but it's back in the car. If you're not wearing the vest when someone shoots you, it's not much help.

That's why the small water hammer arrestors are helpful, because you can put them right at the point where the shock wave is being created, and that dampens the shock right there instead of letting it propagate through your pipes until it finds a weak point to damage. Or, if there are multiple sources of shock that you can't control, you put the arrestor upstream of the thing you're trying to protect.

leonz

Hello Rick,

What you are saying is your hot and cold water feeders do not have copper risers that hold an air slug at the end of your triple loaders to act as an accumulator to accept the system pressure surges when a solenoid valve closes on one of your washing machines is that correct?

You do not need a pipeline hammer arrestor.

A much simpler solution for you is to just reduce the system inlet pressure after the water meter to 30 P.S.I.G. and be done with it, your washing machine solenoid valves and piping will appreciate it as they do not require 80 P.S.I.G. to operate and you will continue to have adequate flow.

Reducing the system inlet pressure to 30 P.S.I.G. will also eliminate the filter cartridges from collapsing as well.

109A_5

" I would want protect a prototype water filter design from exposure to "water hammer". "

"Prototype" is this to be eventually to be sold to the public ?

I would venture to say if the prototype can't handle "Water Hammer" it is already a failure.

RickDelta

@109A_5

Well …….. the schedule 80 PVC (pressure) I built the prototype with was rated for 320 PSI working pressure. I'm sure that would be fine to use (cold water application).

I was thinking of using a schedule 40 PVC (pressure) instead as its rated 220 PSI at 73 degrees F.

My concern was of not max working pressure, but the peak pressure spikes.

I think LEON had a good suggestion, regulate down to 40 PSI to quell down the large spikes.

jumper

What Jesmed says. Snubbers at valves. They have to be periodically recharged. Returning to OP's queries. Expansion tanks do help. Especially multiple ones along line. Supposedly a no no? Motorized valves are gentler than solenoid.

hot_rod

Those air traps don't last very long, better to get an actual water hammer arrester that has a piston or mechanism in side. They are not all that expensive.

They are available from 1/4" compression on up.

RickDelta

@hot_rod

Agreed! ….. in speaking with the engineering support for the arresters, they want to see the arrester closest to the origin of the pressure spike before it can propagate backwards thru the supply pipe line.

leonz

That is where they plumb in the air only cushion stacks as well.