Puzzling Issue
We have a puzzling issue that hopefully you will be able to help us with. I don't know what information will be relevant to the solution, so I'll supply everything I can think of.
We live on 1 acre and have a 12 zone system around the house. Our water comes from a well, supplied by a Grundfos Constant Pressure system (ie it only pumps fast enough to keep up with the pressure demand).
The valves in each zone are K-Rain Pro Series 100 valves, which are supposed to be good for systems fed by well water. The heads are all K-Rain RPS 50 rotors and we have 4 - 6 heads per zone.
The system is about 3 years old.
We have 4 zones out of 12 that have issues, and the issues are broken into two groups. All of our other zones work ok. The zones with issues are split among 3 different manifold boxes and the other zones in those boxes seem to work fine.
Issue 1 - (two zones with this issue) I manually turn on the zone (by loosening the solenoid) and water sort of leaks out of the heads, but certainly not enough pressure to raise them, no matter how long I wait.
Then I turn it off, turn it on again and poof it works perfectly throwing water 20 - 30 feet.
Issue 2 - (two zones with this issue)I manually turn on the zone and it pops up like it is going to work for about 10 - 20 seconds, throwing water about 3 feet out from the heads, then all the heads slowly sink back into the ground and just leak water. I turn it off, turn it back on and the same thing happens... pops up for a few seconds, then drops back down.
I replaced the diaphragm in all of the valves I had trouble with and I'm still having the same trouble.