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bosakie

Senior Member

Posts: 16

Location: USA

1

Monday, August 22nd 2005, 5:22am

What to use as the main supply line

I have read a number of forums and I am still a little confused about what to use for the main supply line for our sprinkler system.

Some say to use PVC pipe from the supply to the valves and beyond then one can branch off using poly pipe. Others say you can us PVC pipe from the supply to the valves and then use poly pipe as the main and then branch using smaller poly pipe to the sprinkler heads.

I have a rather large area to cover with various zones, drip, spray, rotor. I have a 1" supply from an on demand pump that was installed to accomidate the installation of a sprinkler system.

Any suggestions?

HooKooDooKu

Supreme Member

2

Monday, August 22nd 2005, 6:16am

Let's start with what MOST plumbing codes demand.

Any pipe that is going to be under constant pressure (i.e. before any control valves and known in plumbing parlance as MAIN lines) should either be Sch.40 PVC buried 18" deep OR metal (i.e. Copper).

I don't know if those code change for a system on a pump system as opposed to public water supply.

Then once you're past the valves, you do what you want (copper, PVC, Poly). Each will have it's plus/minus.

bosakie

Senior Member

Posts: 16

Location: USA

3

Monday, August 22nd 2005, 7:25am

Thanks, but after the valves is it better to poly or PVC. I have heard that if is use poly that I will not have as good of preasure.

I am in an area where it will freeze so I know I will have to blow the system for the winter. I just want to make sure that all lines feeding the sprinkler heads are adequate.

Wet_Boots

Supreme Member

Posts: 4,050

Location: Metro NYC

4

Monday, August 22nd 2005, 7:29am

There's no depth requirements for the sprinkler pipe in the codes. I would use sch 40 PVC for the constant-pressure plumbing up to the valves, although you could always upgrade to copper and brass for any interior and outdoor above-ground plumbing, transitioning to PVC once you get underground. You still need backflow protection in the supply plumbing.

Wet_Boots

Supreme Member

Posts: 4,050

Location: Metro NYC

5

Monday, August 22nd 2005, 7:33am

Nothing wrong with poly pipe, and it's recommended for freezing climates. You want to google up a "friction loss chart" and work out the numbers for your particular system.

RidgeRun05

Supreme Member

Posts: 314

Location: USA

6

Monday, August 22nd 2005, 11:08am

I would suggest poly pipe after your zone valves, especially in a freezing environment, because the poly pipe will expand and contract a little better than the PVC, SHOULD water happen to freeze in the line. It is also a lot easier to install (vibratory plow) on existing landscapes. I usually run copper off of the mainline to the backflow and into the ground - then PVC from the ground after the backflow to my zone valves. After the zone valves its all poly pipe. I install in a freezing environment.
Tony Posey
Ridge Run Landscapes

bosakie

Senior Member

Posts: 16

Location: USA

7

Monday, August 22nd 2005, 11:55am

Thank you, that makes life a lot easier. I have 1" copper to the backflow, PVC to the valves, and then Poly from there on. You guys rock. I have been reading this forum for sometime now and have learned a great deal from you comments. [:)]

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