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alf51175
03-22-2007, 09:41 PM
I've got a system that has 5 zones. When the 2nd, 4th, and 5th zones come on there is hammer in the pipes in the house. The system is roughly 10 years old. I am leaning towards it being valve problems. If someone has experienced this problem and you could help, I would really appreciate it.

Thanks

londonrain
03-22-2007, 09:44 PM
high pressure with high flow and the valve shutting down is causing your water hammer...

alf51175
03-22-2007, 09:49 PM
This happens as the zones are turned on, just as the zones pressure up. Happens for about 5 seconds.

bicmudpuppy
03-22-2007, 10:59 PM
This happens as the zones are turned on, just as the zones pressure up. Happens for about 5 seconds.

The problem is relatively new? The noise you are hearing is vibrations in the pipe because the flow of water in the pipe has reached a velocity that causes vibration. The most probable cause for this is that the valves are closing slower now with age. Irrigation valves close by using upstream pressure. Your controller stops asking zone 1 to be open and tells zone 2 to be open. Zone 1 is slow to close and zone 2 is taking pressure away which makes zone 1 even slower to close. Zone 1 can't close until the pressure in the mainline equalizes. Some controllers allow you to program a delay that allows the zone to close before then next zone opens. Other controllers offer a fixed delay that can be enabled. Repairing all of your valves might not fix the problem if a reduction in pressure has contributed to the problem. (ten years ago, pressure was at 90psi, now it is at 70psi). The decrease in operating pressure reduces a valves rate of closing. A delay between stations or insulating the pipes would be your best alternatives.

alf51175
03-22-2007, 11:09 PM
Thanks, really appreciate it. Glad you guys are here.

Flow Control
03-22-2007, 11:13 PM
ALF: PM me if you need additional help on this

aric43085
03-23-2007, 01:55 AM
What kind of valves are they?

alf51175
03-23-2007, 12:31 PM
They are Nelson's, don't know the model. After sleeping on it and thinking about it, I needed to add that this happens when those zones are turned on and start to pressure up if they are turned on first. Meaning, if I decide to turn on number 4 first it hammers. Which makes me believe that the valves are slow to open. What you guys think?

aric43085
03-23-2007, 01:23 PM
I think it is definitly the valves. I believe those old nelson valves are the same as the rainbird EV. When those valves get older, the diaphram will chatter causing water hamer. The best result I have had, is to replace the bad valves. If it is too much work, I would replace half now and half later. Hope this helps you out.

alf51175
03-23-2007, 02:09 PM
No, all three valves are in the open and easily accessible. I think that is worth a try. Thanks.

Flow Control
03-23-2007, 02:11 PM
ALF: PM me when that does not work

alf51175
03-23-2007, 11:49 PM
ICS, I am here for suggestions. By all means if you have the answer I can use the help.

Greenguy1
03-24-2007, 07:23 AM
I have used Nelson for years and have rarely had a valve go bad, only solenoid problems. I am wondering if it is your back-flow that is causing the hammer? the febco has been known to cause this condition when there is a reduced pressure as that is the character of a reduced pressure atmospheric vacuum breaker, when the valve is first turned on the pressure is reduced while filling the pipes and the back-flow will make and break causing hammer in the pipes, watch for water coming from the back-flow when this is happening.

bicmudpuppy
03-24-2007, 07:33 AM
Since the valves are accesible, manually open them one at a time and see if you hear valve chatter. The valve will "pulse" instead of "rush". I don't think you will get chatter from a Nelson valve. Lots of other problems, but not chatter.

This is sounding more and more like a drop in pressure over time. Have you had a plumber out lately? Is the sprinkler turn on before or after the house shutoff. Check to make sure the meter isn't partially closed, and if the sprinkler tap is after the house shutoff, make sure the house shutoff is fully opened.

alf51175
03-24-2007, 10:58 AM
Ok, the norm here in Birmingham is the pressure at the street is anywhere from 125 to over 200. So you have to use regulators for houses and sprinklers. When I first saw the system it didn't have a regulator, only a Watts backflow. I thought the unregulation could be the problem, so I installed a regulator and the problem still exists. I have tried to turn the valves on manually and they do not come on. Appears to not allow manual operation. Found out the problem only started within the last year.

alf51175
03-24-2007, 11:21 AM
Also, the system is tied in between the meter and the main shutoff for the house.

Flow Control
03-24-2007, 01:30 PM
The noise is coming from the house pipes? How long is the copper run for the irrigation line to the BF? The zones that make more noise are either zones with elevation change or longer lateral runs? There is no set answer when pipes are making noise, I am just trying to get a better idea on what is happening so I can tell you what has worked for me, I also just go done reading up on the issue.

Mike Leary
03-24-2007, 01:59 PM
The plumbers turned us on to a "hammer arrester" that goes anywhere in
the lines, works good. Lack of low-drain check valves can produce hammer
also, how long does the hammering happen, until the lateral is full?

Flow Control
03-24-2007, 03:00 PM
Have to size the arrester to system, we have had little luck with them to date, but as I was reading up I think we were not placing them in the ideal location

aric43085
03-24-2007, 03:29 PM
Yo Alf. Its the valves. Change 1 and try it.

bumper
03-24-2007, 04:31 PM
Believe you said it started about a year ago? and there have been no alterations to the system at all?

and is not clear to me what is hammering, the pipes in/under the house or the valves themselves?

Greenguy1
03-24-2007, 07:00 PM
I once had a unique situation with a valve that would not shut off or come on properly, when I disassembled it the bleed port in the center of the diaphram was plugged with some kind of biological slime it must have snuck in there somehow during construction anyway I cleaned it out and it has worked fine since, no other problems though with Nelson valves, there really is nothing to these valves, a visual inspection of the diaphram is all that is needed, check for cracks or tears or perhaps slime or small particles in the fore mentioned port there is not much else that can go bad internally, I have seen where a small stone scored the valve seat and the valve weeped but it still operated normally, Q. do the valves have 4 screws on top or 6?

bicmudpuppy
03-25-2007, 12:21 AM
I just remembered why I spend so much time here. It is great to vent your frustrations by arguing about how to fix a problem you have no real clue about because the question was vague and open to interpretation! My contrary nature loves it!:hammerhead: :drinkup:

alf51175
03-25-2007, 09:03 AM
Sorry, guys I don't mean to be vague, I am trying to explain without giving too much info that might cause confusion, but looks like too much would have been better, I apologize. Ok, the hammering is coming from the pipes(copper) inside the house. The first three zones and valves are on one side of the house and the last two are on the other. When the second zone comes on, there is a little bit of hammer on that end of the house in the kitchen. When the fourth and fifth come there is alot of hammer on the other end in a bathroom.There is about two to three feet from the initial connection to the supply line and the BF. And I would say the first three valves are atleast one foot below the BF and the fourth and fifth are about three feet below. As far as I know the only altering or service since install is me adding the regulator and replacing the BF with an identical. The valves are a four screw pattern. What I do know is that this only started in the last watering season and the only thing that has changed is I add the regulator and BF. The only other piece of the system that is wearable part that deals with pressure is the valves. And thanks for what you guys are doing if anything at least it gives us something to think about and ponder.

Flow Control
03-25-2007, 11:19 AM
U have a fax number? So I can send a drawing of what usually works for us?

alf51175
03-25-2007, 11:33 AM
Yes, 205-980-9986.

Flow Control
03-25-2007, 12:09 PM
Have a few things to do, expect the fax by 4pm

Flow Control
03-25-2007, 04:36 PM
ALF: Sorry my day has been busy will fax later tonight

Flow Control
03-26-2007, 09:43 AM
Let me know if it does not make any sense to you

alf51175
03-26-2007, 03:35 PM
That makes perfect sense to me. That sounds logical. But would that not have been occurring for the start, when the system was installed 10 years ago? Just a thought to ponder.

aric43085
03-26-2007, 04:08 PM
If the valves are ten years old, then you should replace them.

Flow Control
03-26-2007, 04:32 PM
That makes perfect sense to me. That sounds logical. But would that not have been occurring for the start, when the system was installed 10 years ago? Just a thought to ponder.

Is that meant regarding my fax. Then to be honest with you, you would think so but I have seen it a couple of years after a job was installed.