System Troubleshooting — Sprinklers (continued)
PROBLEM POSSIBLE CAUSE – CORRECTIVE ACTION
5. Valve won't open (a) Plugged controller discharge line or discharge port in pilot valve.
(Hyd. Normally Open – Verify by checking for discharge at discharge line when station is activated. If no discharge,
734-X1-XX) refer to Controller Service Manual.
6. Valve won't close (a) Leak in pilot valve assembly.
(Electric – Replace pilot valve assembly.
734-X6-XXX)
(b) Plugged supply screen on piston.
– Clean or replace screen.
(c) Manual control selector on pilot valve assembly turned to "ON" position.
– Turn to "AUTO" position.
(d) Pilot Valve solenoid inoperative.
– Remove and replace.
7. Valve won't open (a) Control (field) wires severed.
(Electric 734-X6-XXX) – Isolate and repair.
(b) Defective solenoid.
– Replace solenoid.
(c) No power to controller.
– Establish controller power.
(d) No power from controller to solenoid.
– Check for blown fuse and replace.
(e) Manual control selector on pilot valve assembly turned to "OFF" position.
– Turn to "AUTO" position.
(f) No supply from main valve.
– Debris in control tube, main valve assembly and/or communication passages in body.
Flush thoroughly.
(g) Pilot Valve solenoid inoperative.
– Remove and replace.
8. Sprinkler Weeping (a) Damaged or blocked valve seat.
(Slow leak in valve) – Remove blockage and, if necessary, replace valve assembly.
(b) Damaged piston seal or piston assembly.
– Replace valve assembly.
(c) Low pressure on supply line on hydraulic NO sprinklers.
– Check for low pressure reason and correct.
9. Several valves on different (a) Control tubing leak which lowers supply pressure to other stations.
stations fail to close – Turn controller from station to station until a station is reached where only valves on that
(Hyd. Normally Open station stay open. The leak would be in the tubing on that station. Isolate and repair.
734-X1-XX)
(b) Leak in supply line to controller.
– Verify by checking pressure in all control lines.
(c) Leak in controller pilot valve.
– Verify by constant discharge on controller. Refer to Controller Service Manual.
(d) Plugged supply line filter.
– Replace filter if more than 3 psi (0.21 kg/cm
2
) differential exists.
5
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