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brisk

Senior Member

11

Wednesday, July 13th 2011, 10:37am

Thanks. My neighbor's system is 10+ years old, and mine is 4 days old :-(
I didn't really do a good flush of the system after the installation, do you think a jammed diaphragm on the valves could cause the problem?

thanks
I had a kind of similar situation; Kind of because only 2 of 6 zones made the clanging. First, I tried to look at the backflow, but it checked out fine. Then I reduced the flow, but thought the same thing it should be able to handle it. I ended up going to the master valves and changing the diaphragm, it helped a little. Then I went to the two problem zones and changed the diaphragms and the problem was fixed. It is odd to have that many that need to be changed at once, but odd things happen.

Can't explain the neighbor situation either unless you both have old or inferior valves. Maybe your water is really tough on irrigation materials.
Good Luck

Wet_Boots

Supreme Member

Posts: 3,884

Location: Metro NYC

12

Wednesday, July 13th 2011, 11:29am

If you can go to the street and shut off your water at the curb, you could then cut out and replace the old stop&waste valve upstream of your water meter with a ball valve, and gain improved performance.

But before you go to extremes like that, you are going to replace one of your zone valves with one that has a flow control - hopefully you can do this by simply switching bonnets.

What is the total distance from the street to the zone valves?

brisk

Senior Member

13

Wednesday, July 13th 2011, 11:58am

Thanks wet_boots.

I don't think I want to switch the old fashion shutoff valve at this point, I still doubt that this is the problem. As I mentioned in my calculate and test, the flow in the pipe should be able to handle at least 10 GPM, and the max required GPM from my system is 6.12GPM, so it should be ok. The lowest required zones are 1 and 2, which only require 3.48 GPM... I cannot believe my pipe cannot handle 3.48 GPM.

Do you think it could be caused by improper installation of double check valve? or bad diaphragm in the valves?

I have Hunter PGV100 valve w/o flow control do you know if I can just replace the jar head with a PGV101G?

the distance to zone valves 1,2 3, and 4 from street should be less than 150 ft.

thanks
If you can go to the street and shut off your water at the curb, you could then cut out and replace the old stop&waste valve upstream of your water meter with a ball valve, and gain improved performance.

But before you go to extremes like that, you are going to replace one of your zone valves with one that has a flow control - hopefully you can do this by simply switching bonnets.

What is the total distance from the street to the zone valves?

This post has been edited 1 times, last edit by "brisk" (Jul 13th 2011, 12:07pm)


Wet_Boots

Supreme Member

Posts: 3,884

Location: Metro NYC

14

Wednesday, July 13th 2011, 2:29pm

150 feet of 3/4-inch copper is a considerable source of pressure loss. When I have a home that's 100 feet from the street, I know I have concerns about pressure lost in the supply line. Don't worry about the double check valve assembly - it is a non-issue. Try a PGV bonnet with a flow control. Try reducing flow in one of the banging zones.

Another possibility for reducing the initial rush of water into a zone, is to have all check-valve heads.

brisk

Senior Member

15

Wednesday, July 13th 2011, 3:42pm

Thanks Wet_Boots.


thanks to confirm that DCV is a non-issue.


The point I had the pressure checked (65 PSI) is only 8 feet away from the master valve, and master valve is only 1 foot away from the zone valves (to be precisely, to the first 4 zone valves). So it shouldn't matter how far my zones from street, as long as I have 65 PSI a few feet away from the zone valves, then I shouldn't have too much pressure loss. Am I correct?
150 feet of 3/4-inch copper is a considerable source of pressure loss. When I have a home that's 100 feet from the street, I know I have concerns about pressure lost in the supply line. Don't worry about the double check valve assembly - it is a non-issue. Try a PGV bonnet with a flow control. Try reducing flow in one of the banging zones.

Another possibility for reducing the initial rush of water into a zone, is to have all check-valve heads.

Wet_Boots

Supreme Member

Posts: 3,884

Location: Metro NYC

16

Wednesday, July 13th 2011, 4:48pm

Your pressure measurements don't mean squat when the valve opens, because the losses caused by the initial rush of water into the zone is what sets up the oscillation.

brisk

Senior Member

17

Wednesday, July 13th 2011, 10:34pm

Thanks. Is this so called water hammer?
also, can I reproduce this w/o sprinklers? for example, open all cold water faucets in home?

thanks
Your pressure measurements don't mean squat when the valve opens, because the losses caused by the initial rush of water into the zone is what sets up the oscillation.

brisk

Senior Member

18

Thursday, July 14th 2011, 7:15am

Sorry, I re-read my post, I think I have confused you.

The distance between street pipe and the water meter is around 60 ft. from street pipe to zone 1,2,3,4 valves are around 80ft.

not sure if this makes any difference.
150 feet of 3/4-inch copper is a considerable source of pressure loss. When I have a home that's 100 feet from the street, I know I have concerns about pressure lost in the supply line. Don't worry about the double check valve assembly - it is a non-issue. Try a PGV bonnet with a flow control. Try reducing flow in one of the banging zones.

Another possibility for reducing the initial rush of water into a zone, is to have all check-valve heads.

Wet_Boots

Supreme Member

Posts: 3,884

Location: Metro NYC

19

Thursday, July 14th 2011, 11:58am

You can't reproduce the effect in your home, because there isn't a diaphragm valve maxing out the supply. Get to work on the given solutions and stop asking questions. :evil:

brisk

Senior Member

20

Thursday, July 14th 2011, 1:52pm

Thanks Wet Boots.

yes, I am going to check if I can just replace the bonnet of the 100G with 101G.

I also uploaded a video, can you please let me is this is what you think it is?

http://www.youtube.com/watch?v=b0GPSKi4v0c

thanks
You can't reproduce the effect in your home, because there isn't a diaphragm valve maxing out the supply. Get to work on the given solutions and stop asking questions. :evil:

This post has been edited 1 times, last edit by "brisk" (Jul 14th 2011, 2:00pm)


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