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Tim57

New Member

Posts: 13

Location: Seattle, Washington

11

Monday, September 18th 2017, 1:01pm

I'm
on a flat to gentle slope from the meter downhill across the entire landscape.



Could
I safely install the individual anti-siphon valves in a single box at what
would be the same elevation as the nearby meter and the highest point on the
landscape? This would center the valve box between the meter and the controller
thereby reducing the wire run to a single conduit. Of course some nearby sprinkler heads would be
at the same or even slightly higher than their control valve given the valves
would be installed below grade.



I've
probably answered my own question as your tutoring might be paying off. In that
case, I would have to place those valves/wiring somewhere else below the
sprinkler heads they control -- right? If this is the case, would I be better off
installing a PVB (testing not enforced,) so I can use plain zone valves and keep
all valves (5) in a single
location making wiring shorter and simpler? Also, I would prefer not
to have exposed valves.Your opinion please.




If
I add the well later on I will add the RPZ at that time. I don't know why I didn't think of this before.


Thank you very much.

Wet_Boots

Supreme Member

Posts: 5,287

Location: Metro NYC

12

Monday, September 18th 2017, 2:20pm

Anti-syphon valves are above ground, above grade, just like a Pressure Vacuum Breaker is above ground. No box. For any home with a basement water meter, the ASVs are next to the house, and minimal wire is needed. Since a house usually has a 'utility area' where air conditioning units and/or gas meters are located next to the foundation, that gives you an area where above-ground plumbing can live, even it it's several feet in height (remember that the ASV/PVB/AVB [vacuum breaker] has to be a foot higher in elevation than any pipe or sprinkler they feed)

Above ground valves or plumbing is not a problem. In fact, exposed ASV zone valves are easier to service, and can be manually operated, and the above-ground control wires are not subject to being chewed by rodents.

One likely benefit of a next-to-house valve manifold, is the simplicity of connecting it to a well, should you get one.

Tim57

New Member

Posts: 13

Location: Seattle, Washington

13

Wednesday, September 20th 2017, 10:37am

Thank you....I think I got it. Now, just a couple more questions:

1. The 2014 design Rain Bird provided me calls for 1-1/4" Sch. 40 pipe. Is there a push away from 1-1/4" to 1" pipe? My local Home Depot lists the 1-1/4" as WDV pipe.

2. What brand of valves and sprinkler heads do you recommend?

Thanks again.

Wet_Boots

Supreme Member

Posts: 5,287

Location: Metro NYC

14

Wednesday, September 20th 2017, 7:29pm

1-1/4 pipe would be a good choice for a 20 gpm flow, and that's about what you specified. The odds are very good that you could alter a design and operate it on 15 gpm or less, for the 10,000 sq ft you are covering. An extra zone or two can be a lot cheaper than to have to upsize all the plumbing. Antisyphon valve recommendation would be the Irritrol 2713 APR, pretty much an industry standard by way of a decades-long production history. An inline valve of the same make would be the Irritrol 2500F. Rainbird makes the DV100F inline valve, that contains some internal screening that might help if the water supply is a well, which might pump some sand that city water won't have. All the recommended valves have flow controls.

Rotor head recommendation would be the Rainbird 5004.

Tim57

New Member

Posts: 13

Location: Seattle, Washington

15

Thursday, September 21st 2017, 12:18pm

Thanks again for your patience.

I'm still a little confused about whether I should come off my 5/8" meter with 1" or 1-1/4" pipe. I'm willing to go as large as needed to provide the greatest capacity possible with the 5/8" meter. I guess my question is, if my 5/8" meter at static 86psi is pushing 19gpm through a 3/4" brass pipe at the meter, is the larger 1-1/4" really going to make a difference at the zone pressure and volume?

If you say 1" from the meter through the valves and all the way to the sprinkler heads is sufficient, then that's what I'll do.

If you say 1-1/4" from the meter to the valves and 1" from the valves to the sprinkler heads would provide a little more capacity, then that's what I'll do.

If you say I should calculate my zone flow requirements based on my design and size my pipe accordingly, then that's what I'll do. I just need to know how to do those calculations.

P.S. Thanks for your convincing argument about using simple yet effective and reliable ASV's over the expensive brass back flow devices....I think ASV's are going to work great for me!

Have a great day!

Wet_Boots

Supreme Member

Posts: 5,287

Location: Metro NYC

16

Friday, September 22nd 2017, 10:23am

Go ahead and use 1-1/4 inch pipe between meter and valve manifold. That said, don't worry too much about gaining "maximum flow" to water what sounds like about a half-acre property. You are better off keeping zones at 15 gpm or less. For a start, the maximum rated capacity of the old-standard 5/8 water meter is 15 gpm (although newer designs can have higher ratings) and the flow capacities for 1 inch pipe favor a 15 gpm flow as a practical maximum. If backing away from your 19 gpm flow number means you need an extra zone or two, you will likely find that avoiding the need for larger pipe in your zones can more than pay for the additional zone valves.

You might want to make your connection, and then do another flow-and-pressure test. That can also be called a bucket test, where the pressure gauge is upstream of a flow control that you adjust to a point of a water pressure you can work with. Dial in your pressure, then see what your flow is at that pressure. Repeat the process for several different pressures, and make a chart of the flow-and-pressure numbers you observed.


Tim57

New Member

Posts: 13

Location: Seattle, Washington

17

Saturday, September 23rd 2017, 6:43pm

Okay, a couple more questions:
1. With a static 86psi coming off the meter, do I need a pressure regulator valve? It seems to me that I'm coming off the 1-1/4" mainline with a 1" pipe to my zone valve. If the 2713 APR will handle the pressure at this point then I can always adjust the valve as needed for each zone. Your thoughts?
2. What happens with the water left in the mainline after the winter? It seems that this water could be siphoned into the house supply line when the mainline is opened in the spring. Your expertise please?
Thank you again....

Wet_Boots

Supreme Member

Posts: 5,287

Location: Metro NYC

18

Sunday, September 24th 2017, 9:39am

No regulator needed. As for winter, You want to drain the mainline running from meter to house, just so any above-ground plumbing is cleared of water. (the ASVs allow water to drain from the downstream side - your manual drain will take care of the upstream side)

If you add a hose bib to the upstream side of the manifold plumbing, that would be your air connection for winterizing the sprinklers. Seattle seems to avoid the cold winter temperatures, for the most part, but historic lows are definitely the sort of thing that would damage a system with water still in it.

The plumbing rules actually consider a mainline upstream of the backflow prevention as part of the potable plumbing, so you don't worry about the water it contains being contaminated.

Tim57

New Member

Posts: 13

Location: Seattle, Washington

19

Monday, September 25th 2017, 11:57am

Remember, my irrigation mainline comes right off the "T" at the meter. The other side goes to the house. I was referring to the water between the ball-valve controlling the flow from the meter to the zone control valves. I wasn't planning to have a manifold. I was planning to run my 1-1/4" mainline from the meter (located on the NE corner of the lot) along the northern (highest elevation) property line tapping into it with 1" (2713APR) zone control valve elevated at least 12" above the highest sprinkler head being serviced by the valve. The valves will be protected by the fencing along the line. I guess I could place a drain valve immediately downstream of the main shut-off ball valve that could be opened to drain the irrigation mainline. Your thoughts please.


Wet_Boots

Supreme Member

Posts: 5,287

Location: Metro NYC

20

Tuesday, September 26th 2017, 10:10am

A fenced border on which to locate valves changes everything. It even allows you to have a flowerbed bordering the lawn, providing a buffer between plumbing and lawn. (you really don't want the pipes sticking out of the grass area)

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