Water Hammer


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Old 05-06-21, 07:51 AM
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Water Hammer

I have recently, in the last few months, noted water hammer on any water device opening or closing. Water hammer was only normal when I changed my washing machine hoses from rubber to stainless no-burst hoses 10 years ago, although it was onlt there. Here recently, the hammer is throughout the house.
One pluming problem I had in the plumbing before, was the tempering valve to the toilet. It was backflowing hot water, so that when I turned on cold water on the sink, 90F water was coming out of the cold water tap for about 30 seconds, before it would turn cold. I suspected the tempering valve. So I installed a check valve. Problem solved.
I am now wondering if something, again, is going on with this tempering valve to cause the water hammer. I have no expantion tank on either side of the Domestic water, H&C... a few years ago the well tank setup, including that pressurized tank for the well pump to maintain line pressure, was replaced along with a new pump to deliver 40-60PSI, it originaly was 30-50PSI. I must say I do enjoy the higher pressure albeit only 10 pounds delta P.
Do you think the tempering valve is the culprit or has a pipe support in the wall let go? Its rather difficult to identify where the noise originates from. Is there a way to isolate or track down the noise? Im an HVACR tech so I do have many diagnostic tools, including ultrasonic.

 
  #2  
Old 05-10-21, 09:56 AM
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I haven't seen a tempering valve cause water hammer. It's usually pressure-based, but if yours is maxing out at around 50psi, that's well within normal operating pressures.

I have run into loose or worn washers being the cause of a jackhammering type noise in the plumbing. But it doesn't sound like that's what you're experiencing.

I have no expansion tank on either side of the Domestic water
But you do have an expansion tank where the well supply comes into the house, correct? That is an expansion tank for the whole house.
 
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Old 05-10-21, 04:27 PM
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Tank??.

THe well expantion tank?..hmmm . Maybe i should check the pressure there. It shouldnt be that because that only stores pressure as a reserve demand, to prevent the pump from short cycling, but, who knows..... weird things happen. Its worth a try.
 
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Old 05-10-21, 06:19 PM
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Water hammer

Tried to drain the lines and recharge, no success. Lowered the ci and co on the pump pressure from 68/44 to 58/38 , tank is @36. That didnt work either. I think it just must be a loose pipe clamp somewhere.
mmm mmm m😤😤😤
 
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Old 05-10-21, 09:57 PM
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Bang!

Anything with a fast open/close solenoid is supposed to have a water hammer suppression device dedicated to that fixture, installed as close to the fixture as possible. Clothes washers, ice makers, dishwashers are examples. That fast moving water energy has to go somewhere and when you slam off a faucet the kinetic energy often comes out as sound, the banging noise. It could be a loose pipe but you may want to insider adding hammer arrestors or an expansion tank. Clamping down any loose pipes you see is also advisable, as the next steps get more difficult.
 
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Old 05-11-21, 10:13 AM
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pump pressure from 68/44 to 58/38 , tank is @36
I think the tank pressure is way too low. I don't want to give incorrect info - but can someone else who's more well-system-smart confirm?

But, I don't think that has anything to do with the water hammer.
You say that it's happening on all the fixtures? When you close your kitchen sink or bathroom sink, does it still hammer? What if you close the faucet slowly, does it change?
 
  #7  
Old 05-13-21, 07:44 PM
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Slow close

If i close it slowly it doesn’t hammer. Well pressure tank setting is supposed to be 2psi below the cut in set point, so it is correct.
adjusted C/I 38 PSI, Tank pressure 36 PSI....
 
 

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