Sprinkler systems need to have all the water blown out of them before the first frost sets in, as this can cause the remaining water to freeze. Freezing water in the sprinkler system can be very damaging, causing problems such as the following:
Cracked PVC piping
Cracked brass body
Damage to internal components
In order to avoid damage done to your irrigation system, you need to winterize the system. If you live in an area where the frost level extends beneath the depth of the installed piping, winterization is mandatory. There are three types of water removal:
Let’s discuss how to winterize your irrigation system using these three methods.
When the manual valves are located at the end and low points of the sprinkler, you can use the manual drain method. Shut off the irrigation water supply and open the valves. When the water has drained from the mainline, open the drain cap and waste valve to drain the remaining water that is between the irrigation valve and backflow device. When all the water has drained out, close the valves.
When the automatic drain valves are at the end and low points of the piping, you may use the automatic drain method. Shut off the irrigation water supply to activate the system. All pressure will be relieved, and the water will drain out of the mainline. Once this has finished, open the drain cap and waste valve to drain excess water.
The blowout method is one that deserves extreme caution and care. You will need protective eyewear. It is recommended that only a professional perform this type of winterization method since it uses compressed air from an air compressor to blow all water out of the valves.
If you do choose to use an air compressor on your own, stick to a 10-cfm compressor and hose, and set the air pressure regulator to a maximum of 80 psi for rigid PVC systems and 50 psi for flexible systems. Turn off the water supply, open the manual drain and connect the air line to the blowout port. Connect the other end of the air hose to the compressor and blow out the line. Blow out the system zone by zone so that the heads pop out and the water spits out.