pressure relief valve
I'm thinking of putting a pressure relief valve in my pump on top (where it goes into the water valves).
I'f one of the valves ever gets stuck shut, pump damage can occur.
1. what would a good pressure be (40lb? 50lb? whatever.....?)
2. Where can I find an inexpensive one that will do the job?
You are correct that a "locked" system could damage the pump, but an "inexpensive valve" may not be the solution. IF that were to occur your valve would have to be able to flow enough water to keep the pump volute from overheating. You also need a pressure setting that is lower than the pump's natural "cutoff" point, yet higher than the pressure when it is watering properly. Too high a setting and it would NEVER open regardless of what is happening with the valves, and too low and it will discharge while the watering is going on.
What's out there that will work?