water hammering


  #1  
Old 03-26-04, 03:54 PM
Rickk
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water hammering

I have installed a few pex home run systems. One I recently did has a hammering problem. I did one down the street with wirsbo and this one with watts. The deck mount is causing the most niose. I have two 50 gallon water heaters (reverse return piping) with my manifolds mounted on a adjacent wall with a expansion tank 4 gallon (set at 45 psi) intalled at the end of the hot manifold. I have a prv on the house and have adjusted it from 25 to 75 pounds witch makes no differnce. why does this house hammer and the others don't? Does anyone know of any solutions other than resperators? Have any of you had this problem before? This basement is going to be unfinished so I have plenty of time to play with it. Rick RPM mechanical
 
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Old 03-26-04, 06:44 PM
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Hard to believe you would have any water hammer problems on a pex system, hammer is caused by excessive pressure and fast closing valve, what brand of faucet did you install?
 
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Old 03-26-04, 07:02 PM
Rickk
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Hard to believe you would have any water hammer problems on a pex system, hammer is caused by excessive pressure and fast closing valve, what brand of faucet did you install?

I have heard that a few times. Is'nt pex suppose to reduce water hammering? lol. It is a plumb trim product, 720615s. Full port valve. The hose bibs and washer box do it to, If i turn them on and off real fast.

What I am thinking:
run larger hot and cold line to the deck mount?
my prv is bad?
install hammer resperaters?
pipe 1" instead of 3/4" from water heaters to manifolds?
somehow put a water restricter on the deckmount to slow down the velocity.
 
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Old 03-26-04, 07:33 PM
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Hammer arresters may help but probably will not solve the problem. Yeah, I also thought pex absorbed the pressure differential and would expand / contract to soften water hammer effects.
I'd look at upping the size of the lines to reduce water flow speed through the lines. There is a critical speed for water hammer and I can't think of it right now.

One other thing for you to consider. I always put expansion tanks on the cold water line coming into the structure. Just the way I was taught. I've seen it everywhere and have heard all sorts of arguements over the years on placement. Even if it should be up or down...Anyway, kick it around a little in your head. Your doing the work...

Good luck with your project, more questions or problems; ask in this thread and someone will answer you.
 
 

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