Here's an interesting one. I have pop-up, rotating rainbird sprinkler heads that seem to be behaving rather strangely. The system was installed 5 years ago and has not been modified. I only noticed this problem this year. When the zone comes on (electronically or manually) the water flows but the sprinkler heads behave as though the water pressure is too low. Within 2-5 minutes they magically pop up to full height and the pressure is perfectly fine for the rest of the cycle. If the zone is shut ...
