I did find a small leak (very small) at the PVC to Iron threaded joint at the pump. The thread on the pump is not the best, but it is all I have, so I laid the heavy duty pink Teflon tape to the joint and have had no leaks since…
However… (does this ever end??)
Now it may run through the 9 zones 4 or 5 times over a two day period without a hitch, but for no apparent reason pull a bunch of air on the 5th or 6th time through and get hung around 15 – 25 psi and thus not shut off.
The following all occur regularly:
1. Runs through all 9 zones with no perceivable issues at all.
2. Sometimes, perhaps midway through a full nine zone cycle (it differs from run to run) all of a sudden a mass of air hits the pump (I am able to tell by the sound, but also visually at the clear filter I installed). In mid cycle the system seems to handle this with no apparent problem.
3. Sometimes, at the end of a full nine zone cycle all of a sudden a mass of air hits the pump (I am able to tell by the sound, but also visually at the clear filter I installed). Because the flow has been shut off as the cycle is over, this appears to cause some type of cavitation, which seems to allow the pump to not drop below 10 psi (low pressure cut off), while not allowing the pressure to build above 25 psi.
Thus the system just runs and runs, builds up heat, eventually creates steam (did this once), but at any rate just keeps running and running.
If I open any of the sprinkler valves and give the system a flow, in about 2 – 3 minutes it is making pressure and working fine. Then nine times out of ten once the valve shuts the system builds to 40 psi and shuts off, and hold about 35psi.
My guess is something is leaking in one of the well points below the check valve???
Also getting very fine sand in the filter…