Sprinkler system connection upgrade - sanity check

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Balint Laczay

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Hi,

I’m upgrading my sprinkler system connection and main piping. I’m looking for feedback, and a quick check if I’m planning on doing anything silly. I’d appreciate it if you pointed out any issues that you think could cause trouble in the future.

At the sprinkler system connection point, there is a 1¼’’ RPZ and a 1¼’’ pressure reducer, piped with galvanized fittings. The sprinkler main line is 1½’’ PVC, and branches at half a dozen places, has long runs (longest is ~250 feet), and supplies about 20 zone valves and a few hose bibs in various places.

My plan is to replace the galvanized piping at the connection point with copper and brass, replace the RPZ and the pressure reducer with new units, and add a water meter. I’ve decided to use 1’’ devices (water meter, RPZ, and pressure reducer), because as long as I don’t run too many zones at once, that should be enough, and it’s much cheaper. I’m also adding isolation valves at multiple places on the main line, to make maintenance easier.

Here is how I plan to pipe the new connection. Staring underground:
  • A PVC 1½’’ pipe splits off from the house’s main water supply line underground.
  • Use a PVC 1½’’ slip x 1’’ MPT adapter threaded into a copper 1’’ FPT x sweat adapter, to change to copper.
  • Run a few feet of copper 1’’ type L pipe horizontally underground, then turn upwards with a copper sweated elbow.
This so far was underground. Now we rise above ground:
  • Insert a sweated copper 1’’ union for serviceability.
  • Use copper 1’’ sweat x MPT adapter threaded into a brass 1’’ elbow to switch to brass and turn horizontal.
  • Connect the 1’’ water meter (with built-in double unions).
  • Then the 1’’ RPZ (with built-in double ball valves).
  • Then turn downwards with a brass 1’’ elbow and two brass 1’’ nipples.
  • Connect the 1’’ pressure reducer (with built-in inlet-side union).
  • Use a copper 1’’ FPT x sweat adapter to switch to copper again.
  • Insert another sweated copper 1’’ union.
Everything so far was above ground. Now we go underground again:
  • Turn horizontal with a sweated copper 1’’ elbow, and run a few feet horizontally.
  • Tee off to two sprinkler main lines with a sweated copper 1’’ tee.
  • Use a copper 1’’ sweat x FPT adapter threaded into a PVC 1’’ MPT x 1½’’ slip adapter to change to the PVC main lines.
I made a very low quality drawing of this:
connection.png


I chose this approach, because:
  • I’ve read that brass underground is not recommended.
  • I wanted to protect the PVC-copper transition from being loaded. So I run a few feet of copper pipe horizontally underground. That way, even if I’m using wrenches on the above ground copper union, it cannot load the underground PVC-copper transition too much.
  • I’ll support the above ground piece in between the water meter and the RPZ, with a unistrut bolted to a concrete pad underneath and to the wall of the house sideways.
What do you think? Is this a reasonable plan? Thanks for your feedback!

Cheers,
Balint
 

Breplum

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Well thought out and pretty much the same principles I subscribe to.
One thing that is ALWAYS recommended is to make sure you have some filter screen before the backflow (RPZ in your case).
A favorite double union PRV that has the screen built in and accessible is Zurn/Wilkins NR3XLDUPR.
Even available in Propress. I would do the entire project in mostly Propress outside of the good choices you made for brass.
Ream all the copper tube. A plumber could press that whole assembly up in about five minutes once you have it put together.
1-Be careful about flow of the particular PRV you are using. Look it up to make sure it will suit your needs.
Note, the higher priced PRVs say, Watts U5B, has much better flow characteristics than the Watts 25AUB.
-Better to upsize a modest flow PRV to insure good delivery, especially once you are sure of your flow needs due to pressure drop.
-Maybe use a expansion/sliding PVC joint at your existing 1.5" PVC to make assembly there easier. The unions alone can be a pain because their faces are not flat. (Note: the union faces of the Wilkins PRV are flat so in the case of failure, a new unit can slide right in.)
 

Fitter30

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Dielectric unions instead of a ground union less torque to tighten. Regulator before rpz have less of varying pressure when valves close. Never heard of a problem using brass underground. Water meters and valves both are used all the time.
 

Seiyafan

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Another good PRV with low fall off pressure to consider is Zurn 70XL
How's the water quality? Do you need a strainer?

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Jeff H Young

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as long as 1 inch meets code and consider if the house has fire sprinklers when shrinking sizes. I mean nobody plans on a fire but mentioning just in case
 
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