Sprinkler System Questions

[crokett]

I am thinking about putting in a sprinkler system. So a couple questions...

Does it have to be below the frost line? I was thinking yes (water in pipes) but my wife pointed out we would not be using it in winter and I've heard of using compressed air to blow out the lines. How hard is this to do myself? I've done plumbing, so actual installation seems straightforward. The sticky bit for me would be designing it - making sure there was proper coverage, enough zones, sizing the pipe, etc. Any idea on cost? Are they priced per linear foot?

[Eric]

Around here there are different companies that go around in the fall and blow out sprinkler systems. Think they usually charge around $50.

I believe it takes a fairly large compressor to get blow out a sprinkler system.

So for as far as that goes, I don't think you need to be below the frost line. You'll never get all the water out, but you'll get enough out to let what is left expand and not bust your pipes.

[footprintsinconc]

as far as i know, you are not going to be installing the system below the frost line. this is because the frost line is going to be at approx. 3ft. that is a ton of digging for put in sprinkler when you are only going to be digging like a 6" wide trench.

here in phoenix, we dont have to worry about that. infact, i still have to water the plants .

when i did my system, there are basically five components to the system:

1. back flow prevention thing (forgot what they call it). this basically prevents the water in the irrigation system to flow back into your house/city.
2. valves that will be installed at the head of each separate line leading to an individual zone. if you are going to be adding a drip system, then just down stream of the valve you will an inline filter and then a pressure reducer so that you dont blow off the drips at the end of the line.
3. you will use schedule 40 pvc piping for lines.
4. you will install a controller that will control the your valves and the timings.
5. then you have the sprinklers. there are basically three type: the spray heads. these have to be placed closer to gather because they cover a small area. you use these when you dont have a large lawn. the other two types are imppact rotor and gear drive rotos. both of these are used when you have large areas. they are similar to the ones we used to water our lawn with in canada. these can be spaced much farther apart and cover a larger area. i am guessing that you have a big area to cover, so i would go with either of the last two.

its real easy to install. you can read up further on orbits website. if you email me, i can email you a couple of pdf files that i have landscaping/irrigation system.

have fun!

[Slik Geek]

Does it have to be below the frost line?

No, six inches is just fine. Any more depth and you'll have an installation and maintenance nightmare. Here in northern Illinois, I haven't had any freezing damage, but my lawn is sloped so I can drain out the lines in the fall at the lowest spot with a small water pump. I have a friend who pours in some non-toxic antifreeze (like that used for RVs, widely available) to be sure that there won't be any freezing damage.

How hard is this to do myself? I've done plumbing, so actual installation seems straightforward.

The plumbing is the easy part. The trenching is the hard part. My wife and two teenage boys helped install our 500 feet of tubing - all hand trenched. It was a lot of work. Probably better to rent a trencher!

The sticky bit for me would be designing it

Take your time on the design - by the time you are done you won't want to add more tubing or re-route it! There are decent online resources (one was already mentioned), as well as booklets available from retailers selling the sprinklers to help. They have guidelines to help you size the tubing properly.

I used the "flexible" black tubing sold at the big box hardware stores, cheaper and faster to install than rigid PVC pipe.

It is much better to place too many taps for sprinklers at installation, and then cap off the ones you end up not needing and hide them just below the surface.

[pelligrini]

Around here we're also required to install a rain/freeze sensor. Which isn't a bad idea even if you're not required to do it.

[maxparot]

Just make sure the lines pitch down towards the last head in each line. that way when they blow the air through the water goes towards the end and out.

[Uncle Cracker]

If the lay of the land will allow you to drain your system completely, then you can go in above the freeze line. Draining can be accomplished through the use of manual drain valves at low points along your mainline (upstream of your zone control valves) and your lateral lines (between control valves and sprinkler heads). Many can use those little automatic drain valves in the lateral lines, but don't use them in the mainline, because they tend to leak in lines that are under constant pressure. Provide a gravel drain sump at each drain valve for soakage.

Compressed air can be used to blow out lines in some cases, but there are two drawbacks. It takes a larger quantity of air than the typical compressor can produce to completely drain the lines (air can pass the water in partially-filled pipes, leaving water where you don't want it), and running air in your mainlines can damage many of today's zone control valves (particularly the cheaper ones).

Many people let water drain out on its own through the lower heads in the zones, but this method is both unreliable to completely drain the system, and often impossible with many of the better sprinkler heads, due to the inclusion of anti-drain valves in the heads to prevent there always being mud puddles around them when the system is in use.

Now a quick word (or many) about design: Any idiot can design a sprinkler system, but to design a system that works properly is more difficult than many will think. The proper placement, spacing and selection of heads is critical to the process, and experience and knowledge of the products is the only way to properly do this. Proper zoning of the sprinklers into logical groups of like heads and water needs, and sizing of pipes are also not common knowledge. If you do a hack job, you may indeed get sprinklers squirting water, but they might not be operating within the proper parameters, resulting in poor coverage (wet and dry spots) and water wastage.

It's a fact that you don't need a million-dollar sprinkler system to cover a ten-dollar lawn, but you also don't need a crappy system if your goal is to have a nice lawn and fewer maintenance liabilities. Management agencies in many states are already holding individual homeowners' fat to the fire to better conserve irrigation water, and it's getting more widespread by the day. People in seasonal states are not immune to this rapidly progressive level of oversight, so best to put together an efficient system now, as opposed to having to live with it later.

You will find that many places that deal in sprinkler DIY materials can do a design for you, either free with your materials purchase, or at reasonable cost, but make sure you are dealing with reputable people, as many of these "designers" might know even less than you do, even though they might try to convince you otherwise. And beware of the folks in the BORGS... Some of them are just plain stupid. I have sat in on the Saturday DIY "classes" many times out of curiosity, and have had reactions ranging from mild amusement to absolute outrage at the utter bullshiit advice being offered.

A professional irrigation designer would certainly be the one to do the best layout for you, but most of these will be too expensive for a typical residential lawn system, so that's probably not a viable option for you. Just sort through the supply houses for knowledgeable people, and get the best help you can afford, whether it be an actual layout, or just good advice.

[DaveS]

As everyone has said so far - you don't have to bury it below the frost line, but you will have to have it blown out each Fall. I usually wait until the guy comes to do my neighbors, and offer him $30 cash, to do mine - works every time.

A few notes:

Nobody uses a trencher anymore - they use a cable puller and pull the lines under the dirt. It just leaves a 1" cut in your lawn.

Laying out a sprinkler system can be a complicated thing. If you read the tutorials on the internet, you will see that you have to do some pretty fancy calculating to make sure you get it right.

Having said that, I think that many sprinkler install companies just lay them out without much thought. This often results in bad systems (some areas too dry, or too wet, or not reached).

My point is this: even if you pay someone to put it in, you might get a bad system.

[ragswl4]

I would make sure to get REALLY GOOD control valves. I have a friend in Palm Springs that went the cheap route on the control valves and he is repairing them at least once a year or more often. Every time I see him he starts off with "That #$%&*^@%$& sprinkler system is broke again".

Also think about components that may need to be removed and consider using threaded unions on those parts. More expensive but the hassle of cutting the pipe, removing, reinstalling and regluing the pipe (expecially on a horizontal run full of water) can be frustrating. Just my $.02.

[Rand]

I have done a couple of sprinkler systems - and repaired a few more than that.
I have the Sunset book on Garden Watering systems which has lots of helpful information in it.

The first thing you have to figure out is how much flow your water system has. The less flow you have the more independent circuits you'll need.

There is a lot to planning a good system. I highly recommend getting the book I mention above.

The systems I have worked on have mostly been PVC in a trench. If you can rent a machine that will pull the flex pipe underground it will save your back!

[pelligrini]

If you have seasonal plant beds give careful consideration to the pipe placement.

The guys who laid in the system at the office we built had lines running all over the place through the beds. The next year the landscapers helper punched at over half a dozen holes in the shallow pipes. The landscaper wasn't all that bright either. He patched the pipe where the water was blowing out the dirt. Then he came back and patched the next hole down the line. Then he came back and patched the next hole down the line. The 4th time he came out he finally did a pressure test. It did provide some entertainment that week.

[rjwaldren]

http://www.irrigationtutorials.com/sprinkler00.htm

I found the above site better than any guide or advice I saw. It walks you through the complete layout and design. It covers all the details of line size, slope/drain and frost line. Make sure to accommodate future changes to the yard.

One thing I learned last year when I did my back yard is this - trenching is best left to someone else. Around here you can have guys come in and trench for you for what I now consider a very reasonable cost.

[JR]

You're getting loads of great advice. I will offer a planning idea. Use the opportunity provided by open trenches to run a pressure line out to the far end of the property. Some day you may want to have a fountain, a hose bib, or something else out there.

Same idea for an electric line. Put some wire in there with a view to eventually powering landscape lighting, the above-mentioned fountain, security lights, whatever.

JR

[Kristofor]

If the lay of the land will allow you to drain your system completely, then you can go in above the freeze line.

Around here nobody goes below the frost line (who wants a lawn full of 5' deep trenches...). Blowing out the lines is of course required.

Even a relatively slow compressor will work as long as it has a decent sized tank if you have relatively small zones. That said, I agree with the previous comments that it's $30 well spent to simply the the pro's do it since it's a pretty putsy job with 6 zones and wait periods on my smaller compressor.

The house behind mine is about a 1/2 acre yard. I watched when their system was installed. As Dave mentioned it was done with a pulling machine with a vibrating blade that went about a foot deep and did fairly little damage to the yard. Total time for the installation was less than 4 hours for a team of 5-7 college age looking guys. Darrin (neighbor) said it cost just under $2800. I would guess if you did it yourself you might save half of that or more (but at the cost of a lot more time invested...).

Personally, I think I'd bite the bullet and pay rather than loose the weekend relaxation time, but then the only thing I've had to do in 6 years on mine (beyond year end blow-out) is unstick a valve once, my opinion might be very different if I was used to seeing lots of problems...

[JR]

The house behind mine is about a 1/2 acre yard. I watched when their system was installed. As Dave mentioned it was done with a pulling machine with a vibrating blade that went about a foot deep and did fairly little damage to the yard. Total time for the installation was less than 4 hours for a team of 5-7 college age looking guys. Darrin (neighbor) said it cost just under $2800. I would guess if you did it yourself you might save half of that or more (but at the cost of a lot more time invested...).

I've never seen one these gizmos. How do the risers get installed? Prior to putting the pipe in? How do you know where they're going to end up?

I think it's still normal to use a trencher around here. Of course if you don't have irrigation in the first place there's no lawn to protect. Nothing grows here without irrigation. I ran a ditchwitch on summer in my youth, and can still do some damage with one. It's WAY better than digging by hand, especially for a large job. And once you've got all the trenches dug you can lay out the sprinlers to fit the yard.

I guess I'm soft of curmudgeonly. "In my day we didn't have these fancy vibrating istaller thingys. A trencher, a hacksaw, a shovel, and a gallon of lemonade is all we had."

JR