Installing an irrigation system

Important Note: Before you begin the work described below, you must draft a complete installation plan on graph paper.

The instructions contained herein describe the installation of an irrigation system from the collectors to the sprinklers.

You will notice, however, that the installation of the plumbing system between your home’s supply network and the collectors is not included. This part of the installation represents a serious plumbing project that requires knowledge of (and compliance with) applicable municipal regulations and standards. It is recommended that you defer to professionals for this part of the project.

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1. Preparing the Area
2. Installing the pipes, fittings and sprinkler connections (risers)
3. Connecting the network to the collector
4. Installing the controller
5. Installing and connecting controller wiring
It is important to note that the plumbing system that links the irrigation system to your residential network must be equipped with a valve that allows the system to be turned off completely, as well as a backflow protection device that prevents water from re-entering the household system. Additionally, a trench must be excavated, up to the location where the collectors are to be installed, in order to complete the installation of the irrigation supply system.

There are three options for connecting the system to the household supply:
  • Directly to the pipe that supplies water to the house (the exterior pipe between the municipal aqueduct and the house). This provides the irrigation system with maximum water pressure and, because it is an entirely external installation, it also eliminates the occurrence of water circulation noises within the home. Keep in mind that this type of installation requires the excavation of a trench (up to the pipe that supplies water to the home) and that in frost zones, where pipes are buried deep in the ground, this can represent a considerable task.

  • To the pipe that supplies water to the house (inside the home, in the basement). This solution, often used in frost zones because the plumbing may be directed outside the house immediately after its connection to the main network, provides for a minimum length of interior piping and saves you from having to excavate, while still providing solid soundproofing potential (to prevent circulation noises within the home). This type of installation also allows the main valve, as well as the drain valve used to purge the system before the frost, to be installed inside. Keep in mind that you will have to drill through the foundation wall to provide passage for the irrigation supply pipe.

  • To the existing exterior plumbing on your home (the pipe that leads to your garden faucet). Though this may be the simplest solution, there are several inconveniences: the farther the connection from the main water supply, the weaker the water pressure; and, every time the irrigation system is engaged, you will hear not only the water flowing through the pipes inside the home but those annoying pipe "knocks" that often occur when the system stops as well (if your plumbing tends to produce them).

If the water pressure available to you exceeds manufacturer recommendations, a pressure regulator must be installed.

As for the type of backflow protection to use, as well as the installation requirements, find out about the applicable municipal regulations and standards in your area.

Once the plumbing – connecting the household supply to the proposed irrigation system – is installed, open the main valve for 5 minutes in order to flush the system and eliminate any particles while ensuring that there are no leaks. Make sure that the end of the pipe is not lying directly on the ground to avoid contaminating the pipe during this process.

Do not bury your plumbing right away.

1. Preparing the Area

1.1 

Connect the collector to the main water supply pipe (the one connected to the household supply network).

1.2 

Place the collector on a gravel bed and install an underground enclosure.

1.3 

Using small flags, indicate the sprinkler locations on the property according to the installation plan.

1.4 

Trace the pipelines with spray paint or using lengths of string (make sure the lengths are taut). If you decide to use spray paint, use a different colour for each station to avoid any confusion.

1.5 

Remove lawn along the painted line or length of string (shovel width) and lay it on a drop sheet to avoid damaging the lawn around your work area.

1.6 

Dig a V groove and place the dirt on another drop sheet. Depth: in frost areas - 12 inches (30.5 cm) for the header line and at least 4 to 6 inches (10 to 15 cm) for lateral lines. Also in frost areas, the pipes must be installed on slight inclines leading to the drainage areas (where the automatic purges will be installed). The depth also depends upon the height of the sprinklers.

*Before digging anywhere on your property, contact the necessary authorities to determine whether there are any wires or pipes buried on your land.

2. Installing the pipes, fittings and sprinkler connections (risers)

2.1 

Cut the pipes to the desired lengths using a hacksaw or PVC pipe cutter. Sand down pipe edges if you use a hacksaw.

2.2 

2- Assemble the pipes using the appropriate fittings to complete your networks (stations), then assemble the risers (fittings that will be used to connect each sprinkler to its network), but do not install the actual sprinklers. Install an end cap on the end of each line (except in frost areas; see below).

Assembly technique for PVC piping:
  • Install Teflon tape on all threaded (male) pipe ends.

  • For ends to be glued, use the following method:
    • Clean the pipe end and the inside wall of the connector collar, and apply the PVC primer.
    • Apply PVC cement on the pipe end and the inside wall of the connector collar (this is not really a glue or cement but a solvent that welds the pieces of PVC together).
    • Insert the pipe end into the connector using a twisting motion and hold the assembly in place for 30 seconds.
    • Wipe off any excess solvent.

Assembly technique for polypropylene piping:
    • Slide stainless steel adjustable clamps over the extremities of the pipes to be connected
    • Insert a connector into the pipe extremities to be connected
    • Tighten the adjustable clamps.

2.3 

Protection against frost
In frost zones, the entire system must be purged before the winter in order to prevent damage to the pipes and fittings. This is done using automatic or manual purges installed at various locations:
  • Main valve (use a valve with integrated purge)
  • Collector (install a manual purge instead of an end cap at the end of the collector)
  • Certain sprinkler heads (according to manufacturer instructions)
  • At the end of each lateral line (instead of an end cap)
  • At the lowest points of the network, where water will tend to accumulate

Note: Lay gravel beds in the locations where automatic purges are to be installed to ensure proper drainage.

2.4 

Once the glue has set, place the piping in the trenches.

3. Connecting the network to the collector

3.1 

Once all the stations have been set in place, connect them to their respective valves on the collector.

3.2 

Allow water to flow through each station for 5 minutes.

3.3 

Install end caps on all risers within the same station (all except one) and open the valve for this station to allow water to flow through it (don’t worry if the end caps aren’t perfectly sealed). This will create a single geyser that you should let run for 2 minutes. Close the valve, plug this fitting, remove the end cap from another fitting and open the supply once again. Continue this until all sprinkler fittings have had their 2-minute cleaning. This step is important as it will prevent sand, dirt and PVC residue from jamming the sprinklers.

3.4 

Mount the sprinklers to the risers and adjust the direction of the spray. In their closed (off) positions, sprinkler heads must not protrude from the lawn by more than 1 in. (2.5 cm).

3.5 

Open one valve at a time on the collector to verify sprinkler coverage in each station (and coverage of each sprinkler head within the station) and to ensure that there are no leaks and no sections that remain uncovered. Make the necessary adjustments, as required.

3.6 

Backfill the trenches (make sure the soil is compacted), reinstall the section of sod, and water the area immediately to ensure that it takes root quickly.

4. Installing the controller

The instructions below describe the connection of a controller (timer) to the collector. The electrical connection of the controller is not addressed (i.e. controllers that require connection to the electrical supply box).

General Rules:
  • In Québec, any connection to the electrical supply box must be completed by an electrician.
  • Remove power before undertaking any connection procedure.
  • Read the installation manual carefully.

5. Installing and connecting controller wiring

If the controller is not designed to withstand the elements, it must be installed indoors, out of the reach of children. It must also be installed next to an electrical outlet (if designed for plug-in power connection).

The cable used to connect the controller to the valves must be rated for underground installation and include wires of various colours (the quantity of individual wires must also exceed the number of valves by at least one).

To better protect the cable from rodents, digging tools and other potential damage, insert it in a PVC conduit.

5.1 

Connect one of the cable wires to one of the two valve solenoid wires (either of the two wires will do). Repeat this for each of the solenoids using a different coloured wire for each connection. Use the extra cable wire (typically the white wire) as the "common wire" and connect it to all the 2nd (loose) solenoid wires. Don’t be concerned if the cable has more than one extra wire as they may be used for the installation of additional valves in the future. They may also come in handy should a valve connection be severed; it is much easier to use one of the extra wires to re-connect the valve instead of trying to find the break and repairing it.

5.2 

Take note of the wire colour for each solenoid.

5.3 

Protect your connexions from humidity using waterproof wire caps (caps filled with waterproof gel) or, if you decide to use standard wiring caps, simply inject some silicone into each cap once the wires have been set in place.

5.4 

Thread the cable to the controller by laying it in the trench where the collector pipe is installed - or in a trench created specifically for the cable. If you intend to install the cable in the same trench as the water supply pipe, try to maintain a distance of 2 in. (5 cm) between the cable and the pipe.

5.5 

Connect the wires to the numbered terminals on the controller according to the previously recorded solenoid wire colours; then connect the common wire to the common terminal.

5.6 

Test each valve for proper operation using the controller’s manual operation feature.

5.7 

Bury the cable, reinstall the section of sod and water the area.
And there you have it! Everything is now in place to ensure that your lawn and gardens receive uniform and timely irrigation. All that’s left is for you to program the watering schedule and admire the automatic and autonomous operation of your irrigation system while you (and your lawn) take full advantage of the summer.
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