Pilot Valve Operation (Model 734-X6-XXX Only)
The main function of the pilot valve is to control the operation of the main valve located in the base of the sprinkler body. The main valve is operated by the release of water metered through the pilot valve when it is activated either manually at the sprinkler or by the irrigation system controller.
Another important function of the pilot valve is to regulate the water pressure to the sprinkler nozzle. Pressure regulation compensates for large variations within the system and maintains a constant pressure for optimum sprinkler operation. The pilot valve is factory set to regulate one of four pressure levels 50 psi (3.5 kg/cm2), 65 psi (4.6 kg/cm2), 80 psi (6.0 kg/cm2) or 100 PSI (7.0 kg/cm2).
The sprinkler operation mode is set using a Toro Selector Tool (P/N
System Troubleshooting — Pilot Valve
Possible equipment failures with causes and corrective action are listed below.
PROBLEM | POSSIBLE CAUSE – CORRECTIVE ACTION |
1.Sprinkler will not turn on (a) No 24 VAC to coil assembly. (Electric Models)
–Measure voltage with a Digital Volt Meter (DVM). Check wiring and controller program.
–Refer to Controller Operating Instructions.
(b)Selector cam in "OFF" position.
–Set to "AUTO" position.
(c)Debris in pilot valve assembly.
–Disassemble and remove all debris. (See Servicing Pilot Valve page 8.)
2.Sprinkler will not shut off (a) Constant 24 VAC from controller. (Electric Models)
–Check for voltage using a DVM. If voltage is present, disconnect wire.
If sprinkler closes, service controller. Refer to Controller Service Manual.
(b)Selector cam in manual "ON" position.
–Set to "AUTO" or "OFF" position.
(c)Debris in pilot valve assembly.
–Disassemble and remove all debris. (See Servicing Pilot Valve page 8.)
System Troubleshooting — Sprinklers
PROBLEM | POSSIBLE CAUSE – CORRECTIVE ACTION |
1.Sprinkler won't rotate (a) Debris wedged between stator and turbine.
–Remove obstruction.
(b)Drive assembly defective.
–Replace drive assembly.
(c)Nozzle base assembly defective.
–Replace nozzle base assembly.
2. Head sticks up | (a) Dirt in riser assembly. |
–Flush out. (See Flushing Procedure on page 7.)
(b)Damaged or missing return spring.
–Replace.
3.Poor distribution pattern (a) Nozzle plugged with debris.
–Clean or replace nozzle.
(b)Nozzle orifice damaged.
–Replace nozzle.
(c)Low operating pressure.
–Determine why system overloaded and correct.
4.Valve won't close (Hyd. Normally Open 734-X1-XX)
4
(a)Leak in control tubing.
–Isolate and repair.
(b)Pilot valve leak in controller.
–Confirm by observing constant dripping from discharge line of controller. Refer to Controller Service Manual.
(c)Foreign object keeping valve from seating.
–Remove, clean and check valve for damage. Replace if necessary.
(d)Damaged piston seal or piston assembly.
–Replace valve assembly.
(e)Valve not properly communicated to tube in body.
–Reassemble if necessary.
