Originally Posted by irritation
I think they had the 15111A but it needed more pressure than most residentials could provide. The clock they had at the time would take up a whole wall in the garage.
Popup impacts and pressure was a real problem. I remember systems of Buckner popup impacts that needed one head pulled up and seated before the zone would come to life. Rainbird had a special retrofit valve for that occasion. It would stay closed until the pressure hit about 40 psi, and then it would open wide, with a low pressure loss, so the last impact would pop up and spray like it was all brand new.
Of course, instead of installing any specialty valve, one could alway try to rework a zone and make one of the impacts into a riser mount. (cheep cheep)