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Control Loop
Normally Closed
Troubleshooting
Problem
Valve does not open.
The 3-way selector ("4") is set to close. Verify knob position.
Inlet pressure is too low.
The Pilot's adjusting screw is
completely closed.
No current.
Faulty Solenoid
Blocked Solenoid.
Blocked pilot.
Valve does not close.
The 3-way selector is in the "Open"
position.
Solenoid base "Manual Override" not
pointing towards port 'AUTO'.
Power is still "ON".
No pulse (Latch Solenoid)
Blocked Solenoid.
Faulty Solenoid
Blocked inline finger filter (2).
Debris on the sealing seat.
Damaged diaphragm.
Unstable
Blocked or damaged pilot.
upstream
pressure.
Incorrect but
stable upstream
Wrong set pressure.
pressure.
©2023 The Toro Company
Toro Ag
1588 N. Marshall Avenue,
El Cajón, CA 92020-1523,
USA
Tel.: + 1 (877) 373-0087 + 1 (619) 596-2495
Fax: + 1 (800) 892-1822 + 1 (619) 258-9973
toro.com
ALT373
04/23
Number
1
Main Valve
2
Inline Finger Filter
3
3-Way Multi-Purpose Pilot
4
3-Way Manual Selector
5
3-Way Solenoid Valve with Base
6
Solenoid Base Manual Override
Cause
Check the inlet pressure.
Check the screw position.
Damaged wires.
Voltage ok, but no click.
Check port blockage.
No water is coming out of
pilot port #0.
Verify knob position.
Check the "Manual Override"
position.
Check the power source.
Damaged wires or bad
batteries.
Check port blockage.
Voltage ok, but no click.
Disconnect upstream tube.
No firm water stream.
The valve is constantly
discharging a small amount
of water.
Continuous water discharge. Replace the diaphragm.
Unstable pressure
upstream of the valve.
Description
Check
Turn the selector to "Auto".
Increase inlet pressure.
Rotate anti-clockwise to allow the valve to respond.
Continue until the required pressure is reached.
Repair or replace the wires.
Change solenoid.
Dismantle and clean. Replace solenoid if problem not solved.
Dismantle and clean pilot ports. Replace the pilot if the
problem not solved.
Turn the selector to the "Auto" or "Close" position.
Turn "Manual Override" of the solenoid base towards port
'AUTO'.
Make sure the power is "OFF" when the valve is commanded
to close.
Repair or replace the wires (or replace batteries).
Dismantle and clean. Replace solenoid if problem not solved.
Change solenoid.
Clean or replace the filter.
Turn the 3-way selector (4) to "Open" for a few minutes
and then to "Close".
If the problem persists, dismantle, clean, and check that
parts are not damaged.
Dismantle and clean. Replace the pilot if the problem persists.
Readjust the downstream pressure as described.
Normally Open
Solution
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