Water Hammer/Resonance?

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GreenGiant117

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Since moving into my house in January 2018 we have been plagued by this occasional banging noise in the pipes when water is shut off.
Looking online I see that it is probably water hammer or resonance, but any examples I have heard don't exactly sound the same.
What we get is either a rapid fire (maybe 4-6 per second) bangs that quickly diminish OR a repetitive slower (1-2 per second) bang that can last up to a minute (that's the longest I've let it go before turning on another faucet)

Couple key points:
This banging can happen from seemingly any faucet in the house
Most of the time I can get it to stop by turning on any faucet and VERY slowly turning it off, sometimes I have to do this multiple times in order to get it to stop
It seems to happen primarily from faucets, I've heard it from a toilet once or twice, but I've never heard it from a shower/tub or spigot
Happens on both hot and cold side, though seems primarily cold water (probably 85% cold and 15% hot)


I cannot see any hammer arresters or anything, though there is a gauge right next to the pump that doesn't really show anything when the banging happens as far as I can tell.


About the setup:
I have a well (250ft) with a 3/4HP pump that I just had to replace last year (this problem predates the replacement)
Original house built in 1986 (2 bed 2 bath)
Addition sometime in the mid to late 90s added another bath on the second floor
Garage addition sometime in the early 2000's added yet another bath upstairs.
The well pressure tank is just inside right before the gauge
The gauge has some sort of spigot attached to it (see attached pictures)

From the pump it goes:
Pump-->Tank-->Gauge-->Iron removal system --> rest of the house
One thing I found weird is that leading up to the Iron removal system it's a 1" pipe, then goes through the tank with 3/4" then back to 1" after the tank (though I'm assuming that's only because the Iron system was installed after).

Would adding a hammer arrester possibly fix the issue?
Anything else I can check?
 

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Reach4

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1. The thing you drew the blue ring around is a pressure relief valve. Typically they release water when the pressure gets to be over 75 psi. The purpose is to save the pump and drop pipe if the pressure gauge were to get stuck on.

2. Putting a water hammer arrestor near the pressure tank will not help.

3. Your house may have old style water hammer arrestors that get waterlogged. Try turning off the water, and let it drain. Open faucets to admit air. How long to drain the water and admit air? overnight, or two hours, I would think.

4. While things are draining, and the water pressure is zero, that would be a good time to check and adjust your pressure tank air precharge. Typically, with a submersible pump, you set that to 2 psi below the cut-on pressure.

5. Drain from the drain valve in your picture. Note sediment. As part of your cleaning, turn on water, drain, turn on water, drain... until you don't get sediment. This is a regular maintenance thing. Typically annually, like checking air precharge, but if your well produces a lot of sediment, do it more often.

I am surprised that hand operated valves cause water hammer. Just to be sure, and your description seems to say this, water hammer is a single bang when you stop the flow of water.
 
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GreenGiant117

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1. The thing you drew the blue ring around is a pressure relief valve. Typically they release water when the pressure gets to be over 75 psi. The purpose is to save the pump and drop pipe if the pressure gauge were to get stuck on.

2. Putting a water hammer arrestor near the pressure tank will not help.

3. Your house may have old style water hammer arrestors that get waterlogged. Try turning off the water, and let it drain. Open faucets to admit air. How long to drain the water and admit air? overnight, or two hours, I would think.

4. While things are draining, and the water pressure is zero, that would be a good time to check and adjust your pressure tank air precharge. Typically, with a submersible pump, you set that to 2 psi below the cut-on pressure.

5. Drain from the drain valve in your picture. Note sediment. As part of your cleaning, turn on water, drain, turn on water, drain... until you don't get sediment. This is a regular maintenance thing. Typically annually, like checking air precharge, but if your well produces a lot of sediment, do it more often.

I am surprised that hand operated valves cause water hammer. Just to be sure, and your description seems to say this, water hammer is a single bang when you stop the flow of water.

3. Your
To respond:

1. I figured it was something along those lines, thank you for clarifying.

2. I wasn't planning to place it there, just wondering if I should put one somewhere.

3. All I see in the basement is pipes, there are the typical bleeders and things near the boiler, but other than that nothing but pipes. What do the "old style" ones look like?

4. & 5. I will plan to drain sometime in the near future, as far as I know there is minimal to no sediment as I don't have a filter anywhere and have never seen any, but will plan to drain every couple years going forward

I'm not entirely sure if it is water hammer or something else, as I said I will get multiple bangs/thunks/tapping sounds anywhere from 5 times to over 100 times until I stop it, just a repetitive bang bang bang 1-2 times per second for upwards of a minute.
 

John Gayewski

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Install a modern hammer arrestor at any offending outlet. Preferably attach them at the stops.

Old "hammer arrestors" would be in your walls and only work temporarily at best.
 

Reach4

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OK, what you describe is something else than water hammer. It might be called machine gunning or an oscillation. I wonder if a pressure gauge could see that oscillation .

Primitive-Water-hammer-arrestors.jpg
The vertical capped pipes are old water hammer arrestors, and they get waterlogged.

But since what you described is not water hammer IMO, I don't know if getting the water drained will help much.
 
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WorthFlorida

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Water hanger is generally referred to as one bang, an oscillating hammer noise is the pressure wave is bouncing around the plumbing like an echo, the rapid fire noise could be stop or supply valves with a lose seat washer vibrating.

First, do as Reach4 suggest, drain the pressure tank and check the pre charge. With the pump off and the lowest valve open, open all faucets to drain the system if any plumbing in arrestors that may be inside the walls as in the picture.

If the hammer still occurs, start closing stop valves at faucets and main supply valves to close off sections of the plumbing. It's to see if one area is aggravating the problem and will also prevent any seat washers from vibrating though typically lose seat washers will vibrate while the water is flowing. Toilet flush valves of the old kind, ball and cock, can vibrate as It closes off the water or a spike in water pressure might temporary open the flush valve for a second or two and it can vibrate.

Lastly, you did not mention the pressure range of you pressure switch. If it's 40/60, try changing it to 30/50.

Adding hammer arresters will not hurt and there should be a set at the washing machine anyway. Typically there are at the washing machine and dishwasher since the valves are closed rapidly with full water flow. You can install two of these at the washing machine that is just threaded on and no pipe cutting needed. It'll probably help with your problem but no guarantee it will be 100%, but it should reduce the hammering occurrence.


Sioux Chief 660-H Mini Rester Water Hammer Arrester
 

GreenGiant117

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So I've been trying to keep a more close ear on it the past few days and here are some updates:

1. There are times that the banging starts when I turn on a faucet, and it will either be a couple quick bangs or a steady banging similar to the banging you hear as warm water flows through pipes, a slow steady bang, wait a second, bang, wait a second, bang etc.

2. There are times even super slow closing of the faucet will not fix the banging, and it can take 2-3 times of turning on a faucet, slowly closing, hearing the banging and repeat.

3. It does not matter which outlet starts the banging or which ends it, for instance the toilet in the garage addition can start it, but the master bathroom faucet (complete opposite end of the house) can stop it.

4. Banging sound seems to be localized to the original plumbing which leads to kitchen faucet and master bathroom, past the kitchen sink/dishwasher/fridge and in the wall going up to the master bathroom, if that matters.

I will try to get some arresters and install them as soon as I can to see if they help
 
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