How To Wire a Sprinkler System
Automatic lawn sprinkler systems are run by a combination of mechanical parts and electrical components that work in harmony to help produce the end result of hassle free watering. A modern irrigation system makes use of electric valves, solid strand wire, and a digital timer to make this process seem almost magical.
Once you learn how a system works, there really isn't much to it, although when you are trying to troubleshoot electrical problems on a system that wasn't built to code you can run into a few frustrations. But a basic understanding of how the electrical part works can greatly help you when trying to diagnose a problem.
Most standard digital controllers or timers run off of 110/120 volts AC. Indoor timers can be plugged straight into a common house electrical outlet, while the outdoor timers will need to be hard-wired from the transformer to the breaker. A single pole 10 or 15 amp breaker from your service panel (normally by the electric meter) supplies the main power source. With approved 14-2 or 12-2 insulated HV wire, the 110 volts is sent to the transformer on the timer. The transformer than steps-down the power from 110 to 24 volts (approximately). The main circuit board or "computer" part of the timer runs on this lower voltage.
The digital timer then has modules or individual spots for different wires that are labeled. Every zone has its' own spot represented by a number. Zone one is "1", Zone 2 is "2", etc... Different brands or models of controllers label this slightly different, but you can easily tell what each spot is for. The master valve is normally labeled "MV". The Common spot is labeled "com".
If you are on a pump/pump start relay system then the master valve spot will definitely be used. If your system is on a pressurized water source then the "MV" spot may be blank unless a true master valve is installed, but it is not necessary and many systems do not have a master valve. To simplify this brief explanation we will assume that there is no master valve.
Okay, each zone on your system has its' own electric valve. Each electric valve has a solenoid with two wires coming from the top. You will use 18 gauge solid strand wire for the system. Since you will need multiple wires it is best to use multi-strand wire. Multi-strand is a group of single, insulated strands of wire grouped together as one for ease of use. Black insulation is the typical cover over the single different colored wires. 18-5 is a group of 5, 18 gauge wires. Each wire will have its' own color such as white, black, blue, green, and red. Most contractors use white for the common wire and the other colors for the hot side.
Now back at your timer you would peel back the black insulation and then strip about 6" of the insulation on the white strand. Then secure the white to the "Com" or common spot by placing screwing down the contact screw or pressing in the clip on other timer models. Then let's say you want to use blue for zone 1. Wire up the blue strand to "1" or zone 1 spot on the timer. Back at the electric valve for zone 1 you would take one wire lead from the solenoid and splice it together with the white wire using a wire-nut. Take the second wire from the solenoid and splice it together with the blue strand. It doesn't matter which wire from the solenoid you use for either the hot or common, as long as each is individually wired.
The common wire is kind of like a negative. It is called common because it is common to all of the valves. Each valve in your system can share the common wire, but each must have its' own individual hot or colored wire. So let's say you have 4 zones. You would need 18-5 strand wire at a minimum. Each valve's hot wire + the common. I like to have an extra strand or two available at the valves for future use encase you want to add/split a zone, or to quickly fix any wire issues that could develop in the future.
If you are troubleshooting wiring on a system make sure to check what colored wire was used for what zone and the common. Not everyone uses white for the common, some contractors use green. To make things more complicated, some systems end up with wire splices in the ground and for some reason there are people who mis-match the colors either on-purpose or out of sheer ignorance which can make wire troubleshooting a nightmare! However, when installing or wiring your irrigation system I recommend that you stick with the same coloring scheme if you have to make a splice.
Scott
http://www.autolawnsprinklers.com
Once you learn how a system works, there really isn't much to it, although when you are trying to troubleshoot electrical problems on a system that wasn't built to code you can run into a few frustrations. But a basic understanding of how the electrical part works can greatly help you when trying to diagnose a problem.
Most standard digital controllers or timers run off of 110/120 volts AC. Indoor timers can be plugged straight into a common house electrical outlet, while the outdoor timers will need to be hard-wired from the transformer to the breaker. A single pole 10 or 15 amp breaker from your service panel (normally by the electric meter) supplies the main power source. With approved 14-2 or 12-2 insulated HV wire, the 110 volts is sent to the transformer on the timer. The transformer than steps-down the power from 110 to 24 volts (approximately). The main circuit board or "computer" part of the timer runs on this lower voltage.
The digital timer then has modules or individual spots for different wires that are labeled. Every zone has its' own spot represented by a number. Zone one is "1", Zone 2 is "2", etc... Different brands or models of controllers label this slightly different, but you can easily tell what each spot is for. The master valve is normally labeled "MV". The Common spot is labeled "com".
If you are on a pump/pump start relay system then the master valve spot will definitely be used. If your system is on a pressurized water source then the "MV" spot may be blank unless a true master valve is installed, but it is not necessary and many systems do not have a master valve. To simplify this brief explanation we will assume that there is no master valve.
Okay, each zone on your system has its' own electric valve. Each electric valve has a solenoid with two wires coming from the top. You will use 18 gauge solid strand wire for the system. Since you will need multiple wires it is best to use multi-strand wire. Multi-strand is a group of single, insulated strands of wire grouped together as one for ease of use. Black insulation is the typical cover over the single different colored wires. 18-5 is a group of 5, 18 gauge wires. Each wire will have its' own color such as white, black, blue, green, and red. Most contractors use white for the common wire and the other colors for the hot side.
Now back at your timer you would peel back the black insulation and then strip about 6" of the insulation on the white strand. Then secure the white to the "Com" or common spot by placing screwing down the contact screw or pressing in the clip on other timer models. Then let's say you want to use blue for zone 1. Wire up the blue strand to "1" or zone 1 spot on the timer. Back at the electric valve for zone 1 you would take one wire lead from the solenoid and splice it together with the white wire using a wire-nut. Take the second wire from the solenoid and splice it together with the blue strand. It doesn't matter which wire from the solenoid you use for either the hot or common, as long as each is individually wired.
The common wire is kind of like a negative. It is called common because it is common to all of the valves. Each valve in your system can share the common wire, but each must have its' own individual hot or colored wire. So let's say you have 4 zones. You would need 18-5 strand wire at a minimum. Each valve's hot wire + the common. I like to have an extra strand or two available at the valves for future use encase you want to add/split a zone, or to quickly fix any wire issues that could develop in the future.
If you are troubleshooting wiring on a system make sure to check what colored wire was used for what zone and the common. Not everyone uses white for the common, some contractors use green. To make things more complicated, some systems end up with wire splices in the ground and for some reason there are people who mis-match the colors either on-purpose or out of sheer ignorance which can make wire troubleshooting a nightmare! However, when installing or wiring your irrigation system I recommend that you stick with the same coloring scheme if you have to make a splice.
Scott
http://www.autolawnsprinklers.com
posted by Irrigationman at
12:09 PM
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