SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

Ryan-
Looks like you've got a pretty decent start to your irrigation system. Good drawing, and you've done your homework as far as measuring water pressure and flow rate. (Which I would expect from a plumber!) I would suggest the Hunter products, but both Hunter and Rain Bird make a decent product.

For your front lawn area on both sides of the driveway I would suggest using rotor type sprinkler heads. Either the Hunter PGP or I-20, or the Rain Bird 5000 series, both of these sprinklers work well with the water pressure and flow rate provided. Same goes for the backyard, I would use a large turf rotor such as those listed above.

For your three strips of lawn on the outside of the sidewalks, I would use a spray type sprinkler head. The Rain Bird 1800 series is a good choice, but Hunter has recently come back with the Pro Series spray heads. They have a much better wiper seal and a much better spring in them, which in turn leads to better retraction of the sprinkler head after the zone turns off. (The 1800 series often has a problem of sticking up after the water is off).

For your controller I would suggest the Hunter Pro-C, it by far has the most amount of options and is very easy to use and program.

You are correct in the fact that you will need multiple zones, without proper dimensions, I couldn't tell you exactly how many, but you will need multiple zones. Also, because of the different precip. rates, you will want to seperate your rotor sprinkler heads from your spray type sprinkler heads. Any other questions, let us know.

A static pressure of 50 psi makes it important to take steps to conserve pressure. Is the poly main IPS or CTS? (poly mains? where is this?) Can the 5/8 meter be swapped for a 3/4? (or one of those 3/4 meters in a 5/8 size) - Hopefully the property is flat, so a Pressure Vacuum Breaker will suffice for backflow prevention.

Design begins with locating heads at the corners and filling in the gaps. Heads will not have much pressure, so don't skimp on the spacing.

Ryan, Is this what you had in mind?

Uhh, problem. You may not be able to confine the spray from a Hunter PGP-#8 to less than a 20 foot radius.

Your situation is a little different than what a contractor with a pipe puller might be looking at. The amount of trenching you'll do won't directly relate to the number of heads. So skimping on the number of heads you use is a pointless economy.

You have 50 psi static pressure. Through the sprinkler plumbing to the heads, you will lose 10 psi. (pipe, PVB, electric zone valve) - So, at the most, the sprinkler heads are looking at 40 psi. And you haven't even turned the water on yet.

This is why I asked about the supply line and the meter. You can get 15 gallons per minute through that line with no problem (and a pressure loss of about 3 psi) Now we get to the water meter itself. AWWA standards for a 5/8" water meter at 15 gpm is 8.3 psi. For a 3/4" meter, it's 3.6 psi

So switching to a 3/4 inch meter buys you as much as five psi extra, making it worth the money (your consumption will cost you a lot more than the base meter charge anyway) From my observations, you don't get nailed until you move up to a one inch meter. (everyone's mileage will vary) By the way, you want to check and see if you face a sewerage surcharge based on your water meter reading. If so, you get a secondary water meter, feeding only the sprinkler system.

For flat properties, it is also possible to ditch the PVB and electric zone valves, for the individual electric anti-syphon valves. The change gains you a few psi (less than five) and costs you no extra. Antisyphon valves are ASSE approved, so they will comply with the National Standard Plumbing Code. The industry standard antisyphon valve is the Irritrol 2713APR (they make a jar-top 2713DPR, but insist on the APR model) - Rainbird also makes antisyphon valves. Antisyphon valve use is not all that common, nationwide. They're common in California, and no one there minds the look of a row of above-ground valves. In some other areas, the sight of any above ground plumbing runs into customer resistance.

Being in southern New Jersey, it is likely you have sandy soil. Hunter heads do not love sandy soil. (few sprinkler heads do)

Given all the conditions, this is a job done best by using mist heads. They'll perform at pressures the rotor heads do poorly at. They will water at a rate compatible with thirsty sandy soils. They will fit oddball spaces like the strips between the sidewalks and the street. Also, mist heads can be fitted with variable-arc nozzles, for those not-square corners. For decades, the Rainbird 1800 popup mist heads have been the best you could get, because of their patented popup seal. If that patent has run out, then the other guys may catch up. (it may be that Hunter's imitation of the 1800 is successfully making an end run around Rainbird's patents) With today's longer grass lengths, use the 1804 head. I've used the 1800 is all sorts of soil conditions, and their pop-down capability is why the other guys chose to imitate Rainbird's head.

It will be more time and trouble to install an all-mist-head system, but not much more money, with you doing the work. The results will be worth it.

Pros wouldn't do an all-mist-head system because of the additional labor involved with the extra heads. (and zones, pipe, and valves) The price becomes uncompetitive.

As for water meters and anti-syphon valves, this is a case of local practices. In fact, the code I cited specifically allows for localities to set tougher standards. And since atmospheric vacuum breakers have been so misused in the past (and today, too) the local dislike of them, and the antisyphon valves, is understandable. (but their use is still in compliance with the requirements of the various regional codes - they ought to, being that they work on the same gravity basis that PVB's do) The secondary water meter is worth running down, however, until you have something definitive in writing, from the appropriate town official. (if no official policy exists - this might be an opportunity to start one) Obviously, all town water usage must be metered, but the significant sewerage charges that are keyed to meter readings have made the separate sprinkler meter (from the existing supply line) more commonplace. Towns don't lose out, because they get enough money from the secondary meter installation to cover their costs, and they sell more water, and also avoid motivating a homeowner toward looking at well water. A few towns I know of handled the sewerage-charge complaints in a simple fashion, by using a wintertime quarterly meter reading to calculate the entire year's sewerage. Just a heads-up to make sure you aren't assuming it can't be done. It is money. If you're stuck with the 5/8 in the supply, you just have to get by with less water, and more sprinkler zones. With richer loam soils, you don't need as heavy a soaking as pure sand wants.

Your best possible work with poly pipe will be with clamped insert fittings (and not the ones that a Home Depot sells) - use funny pipe, brand name funny pipe elbows (Rainbird, Toro), and marlex elbows at each head. Skip the drain valves, and if you use a large compressor for winterizing, regulate the pressure to 50 - 60 psi.