Hunter I20 SS Won't Pop Up
I have an acre of lawn and have a ton of sprinklers, all PGP. When the PGP's need to be replaced, I decided to upgrade to I20 stainless steel sprinklers. I ordered 10 to test them out and when installed, they won't pop up. When I manually pull up the sprinkler with the adjustment tool, the sprinkler works fine, but I can't get the sprinkler to pop up on it's own. I tried 3 zones to no avail.
Is there an easy solution to this problem? Do the SS models need lubrication?