Winterizing Sprinkler & Irrigation Systems
an excerpt from:
Property Preservation Winterization: Contractor Guide & Reference
Outside sprinkler/irrigation systems need to be thoroughly drained. In cold weather areas these systems are typically designed to easily accommodate the draining of the system. Winterization of irrigation systems is best performed by a professional; usually a landscaping company but if you find you must winterize one yourself, these steps are pretty much the standard procedure followed:
- turn off water supply to the system and zip-tie the shut-off in the closed position
- insure your air compressor is capable of blowing out the irrigation plumbing system. Some systems are quite large. A compressor that can supply at least 150 cfm (cubic feet per minute) at a pressure of 75 pounds is sufficient for most residential properties.
- open an escape for the compressed air before attaching the air compressor. You do not want to pressurize a closed system with this amount of air. It is best to operate the system manually if it has more than one zone. Open each zone one at a time but be sure there is an escape opened in each zone prior to introducing the compressed air to that zone.
- blow the compressed air into the system until you see only water vapor or a fine mist of water escaping from the system
- if any damage is found this is the time to repair it if the damage is likely to allow water to enter the system
- remove tops from rain sensors and place them where they can be found and replaced – normally in a bag and paced in the control cabinet
- open and zip tie in the open position in system drains that will not let water enter. Open only those that will let water out.