Each winter your irrigation system will need become 'winterized' to prevent drinking water lines from freezing and cracking. This involves blowing out the system with compressed air and turning the main valve away and off to prevent water from flowing back into the system and freezing.
Winterizing your lawn sprinkler system is very simple but has to be carried out in a proper way.
Turn Sprinkler system offTurn off the water to your irrigation system at main valve.Deactivate electronic controller(s) and the valves in the systemDrain all of the water out of the watering by air compressor
For the simple reason that even after you have drained water out within the system, it is much better to call a professional contractor for winterization due to, there could be water remains in the pipe that can freeze, expand and crack the PVC piping. Polyethylene pipes are more flexible and can expand under pressure but, water left inside could freeze and burst the pipe walls. Freezing water in the backflow preventer will damage the internal mechanism.
It is recommended if you have a qualified licensed contractor performs a blow-out method to winterize your lawn watering. Serious personal injury may result if you do not proceed with care. One small mistake and might no longer own a lawn sprinkler system.
To winterize your lawn sprinkler system, you will require a commercial size air compressor. You need to carefully attach the compressor to your mainline through a quick coupler, hose bib or other type connection, which is at after the backflow toy. Shut off the irrigation water supply, close the compressor valve then attach the air compressor hose to the fitting. Then slowly open the valve on the compressor. The blow out pressure should NOT exceed 80 PSI.
You can start activating each zone from the furthest zone from the compressor slowly working your direction to the closest zone to the compressor. Keep each zone activated until no water remains within the heads. Once the zone is dry, do not continue to blow air through the pipe. Continuing to blow air through dry pipe can harm.
Turn off the controller after you are done blowing out the systems. You can install the threaded caps over the open ends of the backflow preventer risers and any fly out fittings to keep garbage out until spring. Keep backflow preventer inside for that winter.