The rule thumb for draining a sprinkler system is to drain more than half the water out. But since water most likely will collect in low areas, the system should be “blown out.” Since most of the sprinkler systems aren’t geared for this, it’s better to have a professional irrigation specialist do it for safety reasons.
Steps to winterize a sprinkler system
Step number one: Shut Off Irrigation
The first thing which is done is to close off the irrigation main shut-off valve. This is normally found before the backflow prevention device along the main irrigation line. If there isn’t a shut-off valve installed, you may want to think about having one installed by a professional Colorado Springs plumber. It should be installed where the irrigation line is connected to the waterline for the home. It should then be covered with a valve box to protect it. Another thing to keep in mind is not to use the backflow valve as the main shut-off. This valve needs to drain so it should be left partially open.
Step number two: Open Drain Valves
Find any manual drain valves and open them up. A lot of sprinkler systems have either manual or automatic drains which are placed at low points. This way the water in the system can be drained out by gravity.
Since there will always be uneven part distribution in the system, it will not always drain evenly though so water will form pools in low areas. Also, a drain can sometimes be either stuck shut or stuck open. This can cause a drain to either stop draining water; or waste water when watering a lawn. If the sprinkler system has check valves in it, then these valves can stop water from draining. Air will need to be let in for the water to come out. For this to be accomplished, all the sprinklers in the sprinkle zone will need to be propped up at the same time.
Step number three: Regulate Backflow
To winterize the backflow, the test cocks need to be turned 1/8 turn. The closing ball valves need to be turned at 1/8 turn; or they can be left at 45-degree angles. Additionally, make sure all the valves are insulated. This is especially important if they are above ground. Even a small amount of water that freezes can cause a great deal of damage.
Step number four: Winterize the Controller
This is the easiest of all the steps, but it’s also the most overlooked. The automatic controller needs to be winterized. This is easily done by disconnecting the common wire from the controller. The common wire will be marked “COM” or “C” and is where the valve wires connect.
If this step isn’t done then the winterizing won’t be effective if the controller decides to energize the system accidentally. This can freeze the pipes as well as cause an ice buildup on the sidewalks and a host of other problems. Also, unplugging the controller is not a solution because power is needed to keep the microprocessors warm.
If the system is going to be “blown-out”...
One of surest ways to make sure that the sprinkler system is winterized is to have it blown out. This should be done by a professional plumbing contractor. One reason is that ANSI-approved safety eye protection must be properly worn because high air pressure can be dangerous if a person were to lose control of an air pressure device. There’s always the possibility that an improper job may blow pieces apart too in a sprinkler system. Also, it’s not advisable to stand near or over any part of the sprinkler or valve when a compressor is being run so an expert is the best person to call.
You can winterize your sprinkler system yourself; however, to make sure it’s done correctly and all the water is removed, hire a professional irrigation plumbing specialist.