Do I need a pressure reducing valve?

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Old 04-02-20, 05:55 AM
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Do I need a pressure reducing valve?

I notice a subtle but audible water hammer when valves suddenly close in my house. I got a gauge and measured my incoming water pressure is 65 psi. I am on city water and there is currently no reducing valve installed. I believe 65 is on the high end but not catastrophically. Is it worth me trying to install one?
 
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Old 04-02-20, 09:13 AM
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Pressure reducing valves are now required in many areas but it is NOT required that they be retrofitted to homes that don't have them. I personally wouldn't bother if your pressure stays at 65 but if you monitor your water pressure over time you'll likely see that it changes throughout the day. If the peak is 65 I still wouldn't install a PRV but if it's more than 80 I would.

I do not think a PRV will help with your water hammer. For that you should install water hammer arresters at the appliances that are causing the problem. Clothes washer, dishwasher and ice makers are a few applianes that have solenoid valve that open and close very quickly and are common culprits of water hammer but it can also happen if you quickly close a single handle faucet.
 
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Old 04-02-20, 09:34 AM
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I'd monitor the pressure overnight. I'm on city water but live on top of hill without a PVR installed. I average 25-30psi during the day but have recorded 50psi spikes overnight. You need to know how high it gets.
 
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Old 04-02-20, 10:43 AM
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Thanks for the feed back.

I will set up my security camera to take time lapse photos of the pressure gauge and let it go for a day or too.

The dishwasher and washer machine are definitely the biggest culprits of the hammer. However, I do notice it when turning faucets on and off.

I wonder if the problem isnt so much that I have a strong water hammer but more so just poorly secured pipes. I assume some degree of a water hammer will always occur? The previous owners relocated the boiler from the basement (flooded once) to a ground level supply closet. During this move, the plumbing was reconfigured with a combination of copper pipes and PEX runs through the difficult to reach spots that are connected in series. I am not sure there are any brackets securing the copper pipes that come from the boiler and eventually connected to the pex. Maybe securing those pipes will help?

What arrestors would you recommend? A large, whole house like unit or the single ones at the equipment connections? Any brands better than others
 
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Old 04-02-20, 02:50 PM
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Water hammer arrestors need to be located as close to the fixture/appliance as possible. It's the mass of all the water moving through the pipe suddenly slamming to a stop that causes the hammering. So the arrestor needs to be close to the fixture to absorb that shock in order to work.
 
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Old 04-02-20, 06:27 PM
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These are easy to add to the washing machine. They have similar ones with a 3/8" connector that can be used for the dishwasher.


But you may have found part of the problem too with the loosely attached pipes. There will always be some hammer when the appliances turn off quickly. But a combination of a few straps and the arrestors should probably fix your issues.

Though your pressure may change throughout the day, it sounds like you're likely in a reasonable range. 80psi is the max for residential plumbing, though 40-60 is more typical.
 
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Old 04-03-20, 04:13 AM
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I will set up my security camera to take time lapse photos of the pressure gauge and let it go for a day or too
Your pressure gauge should have a red needle that will record the highest pressure while it's hooked up. On my gauge it's the red needle. It goes up with pressure increases but won't go down until it's reset.
 
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Old 04-03-20, 08:05 AM
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Thanks, Guys. I will keep an eye on my gauge and check out those arrestors. Unfortunately, I bought a gauge that doesn't have the red needle, but I will monitor with the camera. Ill set it up for every 10 minutes to image the dial.
 
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Old 04-21-20, 03:14 PM
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So it looks like my supply pressure holds pretty steady at 65psi without a regulator. Now that I am home all day, I have noticed that every time water runs and stops, I get an audible water hammer, regardless of the fixture.

While investigating the hammer, I noticed another problem. I have a slight drip coming from the cold supply line to a shower mixing valve in my second floor bathroom. I removed the handle and plate at the valve and realized the previous owner put in an array of SharkBite couplers. I think the water hammer is slowly loosening the fitting on the cold line. The drip appears to be getting worse now that we are here more and using water much more.

Redoing the bathroom isn't an option just yet, so the SharkBite connectors must stay. Previous owner created a little access panel to the shower supplies, however, they didn't install shut off valves. Also, I prefer to not kill the water to that bathroom since we do use it.

1) Should I install a regulator and lower to house pressure to 50psi --> will this actually help?
2) Do I really have to install an arrestor at every water supply point? That seems a bit crazy. I have three full baths, kitchen sink, dishwasher, washer machine, two outdoor spickets, and an irrigiation system; all which cause an audible water hammer. Maybe its normal to but it seems like a lot of arrestors to install.

Thanks.


update: I did just go back around in the crawl space and found that the pipe that runs up to bathroom isn't secured at all. The run from crawl space to second floor is a shaft behind my chimney where the pipe shakes freely. I bet securing this pipe will probably stop the leak at the sharkbite fitting.. does this make sense? I dont hear much of a hammer anymore since I temporarily secured it with a wire I had laying around.
 

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Old 04-22-20, 05:29 AM
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1. If your water pressure is pretty steady around 65 psi I would not install a prv.

2. Water has mass and when it's moving it's hard to stop just like a car or train. When you run water and quickly close the valve the hammer you hear is all that water slamming into a brick wall (the valve). The arrestor needs to be located as close as possible to the valve in order to absorb the shock. The further away the arrestor is located from the valve the less effective it is.

If you have a loose pipe that bangs securing it can definetely help with the sound. I don't know how much it will help with a leaking Shark Bite fitting. Most often I see Shark Bites leak when they are under strain so maybe securing the pipe will relieve the strain... or it might make it worse. You will just have to look and see if the leak stopped.
 
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Old 04-22-20, 12:24 PM
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Thanks, PD. I think securing the pipes definitely is my first priority. Its a 1920s house and it looks like they were sloppy when converting to copper and then again when adding several extensions. After that, I will reassess if an arrestor is need at each faucet/appliance.

While securing all the plumbing, I was thinking I could attach a couple of arrestors near the distribution manifold. This would be much cheaper than buying the dozen + I would need throughout the house. I noticed that on both the hot and cold manifolds, there is a capped 1/2" port. Each faucet/appliance is probably about 20ft from the distribution center. Would it help at all if I just install an arrestor at each of these ports? I know its not the best solution and probably not the original purpose of these ports but if it helps a little, maybe its worth a try for now?
 
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Old 04-23-20, 05:31 AM
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I would not bother installing water hammer arrestors 20' away from the fixtures. You'll still have the mass of all that water hitting the brick wall at the fixture.

One option is to replace single handle fixtures with ones that have two knobs, one for each the hot and cold. Modern single handle faucets are very easy to quickly shut off. The older style knobs take longer to turn so shutting off the water is more gradual and is less likely to cause water hammer. Or, just get in the habit of closing valves more slowly. But, things like washing machines, dishwashers and ice makers are bad for causing hammer as their valves can slam shut in an instant. So, if you only want to install a few arrestors I'd put them on the machines first.
 
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Old 04-23-20, 07:01 AM
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will do. Thanks for the help.
 
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