1. On a single water valve if the water valve stops on one port or circuit shut off the pump and open the water valve. Remove the module and rinse it in the pool or with a hose and reinstall it one position clockwise and close the water valve and restart the pump.  If it goes back to the same set of nozzles and stops again then that is a sign that the circuit has a blocked or improperly sized nozzle(s) and that the water valve module is not the problem. Remove the nozzle(s) on that circuit (keeping in mind that each nozzle must go back in the exact same body from where it was removed.  Check the nozzles for debris or jet size. See nozzle sizing
  2. On a dual water valve on the same pump, if the nozzles stay up when there is only pressure on the one valve then that is the module that at the very least need to be cleaned. And may need replacement. If the problem exists only when both valves have pressure, then it is most likely the second valve module. The module with the port connectors should be the first valve. (picture) These modules with the connectors cannot be rotated to test. Rinse them and put them back in the correct orientation.
  3. On a three-valve system on the same pump, if the 2-port valve is not switching from one valve to the other it is most likely the 2-port 5 gear module. Take the 2-port module out and spin the gear closest to the center pin clockwise to make sure it is not obstructed with debris
  4. On any water valve if you see one port on the valve gauge jump more than a couple psi higher than the rest of the ports that is a sign of that nozzle(s) or circuit being partly blocked or someone not putting a nozzle(s) back in the same body it came out of.