Irrigation pipes banging when toilet flushed

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Twowaxhack

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If there is a check valve before the backflow within a foot I think you ok,you need an irrigation guy to check the zone valve you think is faulty
Why would he need a check valve when he has a backflow preventer ?
 

Geofd

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The check valve is to hold constant pressure after the device, I install them everytime I ,or our shop install one we used have chattering backflows, and everytime we fine one that doesn't have one in front of it we install one,
Flushometers,quick opening electric valves lower the water pressure and cause the check valve to chatter it's not for cross contamination just to hold constant pressure on the device
 

Geofd

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The check valve is to hold constant pressure after the device, I install them everytime I ,or our shop install one we used have chattering backflows, and everytime we fine one that doesn't have one in front of it we install one,
Flushometers,quick opening electric valves lower the water pressure and cause the check valve to chatter it's not for cross contamination just to hold constant pressure on the device
Best way to describe it is it stops turbulence on the domestic side from effecting it
 

Twowaxhack

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Seems like that would only cause the backflow to chatter. But if you’ve had success im not going to dispute your experiences.

Thank you .
 

Twowaxhack

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I believe I read that the OP installed a spring type check valve.

Does your shop install spring type or swing type ?

99% of our irrigation systems have their own meter. It’s not directly connected to the house water.

Irrigation meters are not charged sewer fee based off gallons used so everyone utilizes an irrigation meter for all outside watering needs if significant.

We don’t have these problems when a separate meter is used.

A few times I’ve had issues like this.

I installed 2 water hammer arrestors at the connection of the irrigation to the house water and a thermal expansion tank at the water heater. I installed the expansion tank first, no affect on the problem by itself.

It almost completely eliminated the hammer....

The hammer was occurring when a zone valve would shut off in my scenario.
 
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Geofd

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I believe I read that the OP installed a spring type check valve.

Does your shop install spring type or swing type ?

99% of our irrigation systems have their own meter. It’s not directly connected to the house water.

Irrigation meters are not charged sewer fee based off gallons used so everyone utilizes an irrigation meter for all outside watering needs if significant.

We don’t have these problems when a separate meter is used.

A few times I’ve had issues like this.

I installed 2 water hammer arrestors at the connection of the irrigation to the house water and a thermal expansion tank at the water heater. I installed the expansion tank first, no affect on the problem by itself.

It almost completely eliminated the hammer....

The hammer was occurring when a zone valve would shut off in my scenario.
Spring checks mostly regular swings if we don't have spring checks on the shelf we also have separate meters
 

marlonc497

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Yeah in the area I live I don't think sprinkler meters are a thing, its just connected to the house water. The problem occurred before and after a spring check valve was installed so I'm inclined to think that it's not the root cause. Would it be an issue to have a check valve after the backflow preventer? If a faulty zone valve could be the issue I could easily replace it, is there a specific brand or type I should purchase?

Thanks, you guys are geniuses and I appreciate your help!
 

Twowaxhack

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Yeah in the area I live I don't think sprinkler meters are a thing, its just connected to the house water. The problem occurred before and after a spring check valve was installed so I'm inclined to think that it's not the root cause. Would it be an issue to have a check valve after the backflow preventer? If a faulty zone valve could be the issue I could easily replace it, is there a specific brand or type I should purchase?

Thanks, you guys are geniuses and I appreciate your help!
Geofd wants the check valve before the atmospheric type backflow device. So you have it correct.
 

Twowaxhack

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So this banging happens with only one zone valve running when you flush or do you have multiple zones running at once. ?

or this happens if you have no zones running and just flush the toilet ?
 

marlonc497

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The banging, which now I know is the backflow preventer chattering, Occurs when a zone turns on or switches to another. Now I'm not sure if it was a coincidence but it also happened while a toilet was flushed but haven't been able to replicate it in that fashion. I went out to test the zones out today and initially the zones turned on and shut off smoothly, but after a few min of testing everytime a zone would turn on the preventer would expel a bit of water. I don't know why at times everything appears to be fine but other times I get this intense banging that shakes the whole house. I'm afraid of calling out a plumber only for him to find nothing is wrong at the moment but as soon as he leaves it acts up again haha. I will say the problem exhibits itself pretty reliably everytime watering starts which I have set for around 10pm. I am certain that it sometimes occurs when a zone valve opens but I couldn't say if happens midway a zone cycle.
 

frodo

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View attachment 29404View attachment 29405
Here are some pictures, the backflow is indeed higher than the highest sprinkler.
Thanks
first step, strap all that stuff to the building
then buy a water test gauge with a 2nd indicator. this gauge will record a spike
install the gauge on the hose bib and let it sit for 24 hour
high spikes happen at night on city water supply,

If you are experiencing high spikes, the pressure could be causing the problem
1620153640541.png
 

Twowaxhack

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first step, strap all that stuff to the building
then buy a water test gauge with a 2nd indicator. this gauge will record a spike
install the gauge on the hose bib and let it sit for 24 hour
high spikes happen at night on city water supply,

If you are experiencing high spikes, the pressure could be causing the problem
View attachment 29428
Water hammer makes that gauge pretty much useless.



When the hammer starts it’s going to max tattle on the gauge out and not tell you anything other than you have water hammer which you already know is happening.

he’s already checked pressure and it’s around 50 psi.

If he uses that gauge he would need to turn off anything with a quick closing valve or it’ll spike it, not giving an accurate tattle.
 
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Twowaxhack

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Try something for me. Close a stop valve leading to the sprinkler zones so that it reduces the flow from the head by about 1/2. You can turn the system on and observe how far the water is spraying from the head.

I want you to close a stop valve until the spray distance is cut in half.

Then go try to make the hammer by flushing the toilet.

If you can’t get it to hammer, slowly open the valve to let the heads have more water. Keep checking as you increase the flow a little at a time to see when the hammering starts.

Make sure the hammering isn’t only happening on one zone valve. It might be a faulty zone chattering. So if it only happens on one zone it might be that zone valve needs replacing.
 
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Kev123

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Not having a whole bunch of experience at this, I would check your expansion tanks to verify they are working properly and set to correct psi.
 

frodo

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Water hammer makes that gauge pretty much useless.



When the hammer starts it’s going to max tattle on the gauge out and not tell you anything other than you have water hammer which you already know is happening.
That is why i said to strap the damn pipe
he’s already checked pressure and it’s around 50 psi.
he checked it during the day . he did not check at night when it spikes
If he uses that gauge he would need to turn off anything with a quick closing valve or it’ll spike it, not giving an accurate tattle.
Yes you are correct. That is the very reason i said to strap that crap down first.
AFTER, the piping is strapped off. As I mentioned in my GD answer
THEN. install the gauge that I showed.

For those that have no clue
City water spikes in the wee mornings because every one is asleep
a 150 psi spike can ruin that apallo,
As I suggested in my original answer. Strap the pipe, then check for early morning spikes.
IF a spike is occurring. install a PRV on the main line after the meter
 

Twowaxhack

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Yes you are correct. That is the very reason i said to strap that crap down first.
AFTER, the piping is strapped off. As I mentioned in my GD answer
THEN. install the gauge that I showed.

For those that have no clue
City water spikes in the wee mornings because every one is asleep
a 150 psi spike can ruin that apallo,
As I suggested in my original answer. Strap the pipe, then check for early morning spikes.
IF a spike is occurring. install a PRV on the main line after the meter
Strapping pipe doesn’t stop the pressure spike from an auto valve.

In fact it would make the pressure gauge spike higher because the pipe moving dissipates energy, if the pipe can’t move the gauge would read a little higher. True or false ?

So I’m not sure where you’re going with that.,

The tattle wil max out if an auto valve shuts. Ice maker, washing machine, fluidmaster, etc.

Making your tattle tale useless.

so you can’t just leave it on the hose Bibb all night and go look in the morning, unless you isolate from all fast closing valves during the test.

Am I wrong ? I’d love to hear your thoughts.

I do suggest you try it for yourself before you answer.
 
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frodo

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Strapping pipe doesn’t stop the pressure spike from an auto valve.

In fact it would make the pressure gauge spike higher because the pipe moving dissipates energy, if the pipe can’t move the gauge would read a little higher. True or false ?

So I’m not sure where you’re going with that.,

The tattle wil max out if an auto valve shuts. Ice maker, washing machine, fluidmaster, etc.

Making your tattle tale useless.

so you can’t just leave it on the hose Bibb all night and go look in the morning, unless you isolate from all fast closing valves during the test.

Am I wrong ? I’d love to hear your thoughts.

I do suggest you try it for yourself before you answer.
My answer is i have done it dozens of times and you are wrong
 

frodo

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All of the above
the tattle tale registers a rise in pressure the only pressure a solenoid causes is in the immediate vicinity of that valve
If, A solenoid spiked the whole system then a PPP arrestor would only be needed in one bathroom in a building and not at each battery of fixtures
LOL Crazy.. Hey we can do away with water hammer arrestors on the 2nd floor We have one in the basement. LOL LOL

Again. a solenoid is not going to spike the whole system. And it damn sure is not going to spike anything from 50 psi to 150 psi. which is the number we are looking for
Feel free to continue to dig.
 

Twowaxhack

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All of the above
the tattle tale registers a rise in pressure the only pressure a solenoid causes is in the immediate vicinity of that valve
If, A solenoid spiked the whole system then a PPP arrestor would only be needed in one bathroom in a building and not at each battery of fixtures
LOL Crazy.. Hey we can do away with water hammer arrestors on the 2nd floor We have one in the basement. LOL LOL

Again. a solenoid is not going to spike the whole system. And it damn sure is not going to spike anything from 50 psi to 150 psi. which is the number we are looking for
Feel free to continue to dig.
The best way to control water hammer is at its source. That’s why arrestors are placed as close to the source of the water hammer as possible.

This prevents the shockwave from traveling through the system and bouncing back and forth to dissipate its energy.

Strapping pipes doesn’t prevent the pressure spike and shock wave that occurs.

In a house if you install a tattle tale gauge on a hose bibb and make a quick acting valve close it will in fact spike the gauge.

How high the pressure spikes is a function of how much water was moving and how fast the water was stopped.

Cackle all you want......you can’t change physics.

Anyone who has a tattle tale gauge, please Install it and then make your washing machine valves close and see what happens, especially if your home has no water hammer control or expansion tank.

I threw my tattle gauge away because of this years ago.

I’ve had water hammer instances where the gauge hit over 200 psi. Depends on how much water was flowing and how fast it was stopped.
 
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