I am not always good at explaining things so it is probably my fault for not being clear, but the scenarios I described would in fact allow you to troubleshoot and ascertain from your phone which valve the maintenance guy should replace.
Example: you have a 4 zone system that when working is 7gpm in each zone. (for sake of simplification)
-If the Zone 1 Valve is stuck closed, then the flow during the running of zone 1 will be 0 instead of 7 and you tell maintenance guy to replace Z1 valve.
-Same thing for Z2, Z3, and Z4 being stuck closed.
-If Zone 1 valve is stuck open, then the flow rate on zone 1 will still be 7gpm. The flow on zone 2,3, and 4 will now be higher than the expected 7gpm.
-Same thing for Zone 2,3, or 4 being stuck open. The zone that stays at 7gpm is stuck. The other 3 are higher. Replace the valve in the zone that is staying at 7gpm.
-If the master valve is stuck closed, then you will read 0gpm on all zones and need to replace master.
Like I said previously, the only scenario not covered is master valve stuck open…which is really the least important and if there is a leak that develops, the flowmeter would then tell you the master is stuck open.
Hopefully that makes more sense.