Pilot Valve Operation (Model 734-X6-Xxx Only); System Troubleshooting — Pilot Valve; System Troubleshooting — Sprinklers - Toro 730 Series Installation And Service Instructions Manual

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/cm
The sprinkler operation mode is set using a Toro Selector Tool (P/N 995-15) inserted through the body flange onto the pilot valve
D-shaped selector cam. The "AUTO" mode permits automatic operation from the system controller. The "ON" mode opens the main valve
for manual operation and "OFF" mode prevents the main valve from opening.
System Troubleshooting — Pilot Valve
Possible equipment failures with causes and corrective action are listed below.
PROBLEM
1. Sprinkler will not turn on
2. Sprinkler will not shut off
System Troubleshooting — Sprinklers
PROBLEM
1. Sprinkler won't rotate
2. Head sticks up
3. Poor distribution pattern
4. Valve won't close
(Hyd. Normally Open
734-X1-XX)
4
2 ), 65 psi (4.6 kg/cm
POSSIBLE CAUSE – CORRECTIVE ACTION
(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.)
(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.)
POSSIBLE CAUSE – CORRECTIVE ACTION
(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.
(a) Dirt in riser assembly.
– Flush out. (See Flushing Procedure on page 7.)
(b) Damaged or missing return spring.
– Replace.
(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.
(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.
2 ), 80 psi (6.0 kg/cm 2 ) or 100 PSI (7.0 kg/cm 2 ).