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GCO 2431
Irrigation
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Remote Control Valves
The theory of valve operation is the same
regardless of the manufacturer
Two Different Styles of Valves
• Forward Flow
• Reverse Flow
Identifying A Forward Flow Valve
• When looking into the inlet side, you will see the center
of the diaphragm
Identifying A Reverse Flow Valve
• When looking into the inlet side, you will find a wall of
brass or plastic, the diaphragm is not visible
Major Components
Internal Components
Valve Operation
• Forward flow in the closed position
Why does the valve stay off?
• There is greater force above the diaphragm than below
the diaphragm
• Why is pressure not the correct answer?
Force = Pressure x Surface Area
• The pressure above the diaphragm is the same as
below the diaphragm
• The surface area above the diaphragm is
approximately 1½ times greater than the surface area
below the diaphragm, therefore, there is 1½ times
greater force above the diaphragm keeping the valve
closed
Purpose Of The Spring
• It pushes down on the diaphragm so that it wants to
close.
Opening the Valve
• Release the pressure in the upper chamber
– This reduces the force above the diaphragm
• This can be done automatically or manually
Opening the Valve Automatically
• The controller sends 24 VAC to the solenoid
• The solenoid coil develops a magnetic field which lifts
the plunger
• The upper chamber water exits through the exhaust
port
• The force below the diaphragm is now greater
Opening The Valve Automatically
• Water Escapes From The Upper Chamber
Forward Flow Valve Open
Closing The Valve
•
•
•
•
The controller stops sending 24 VAC
The plunger covers the exhaust port
Water is trapped in the upper chamber
The force increases above the diaphragm
Force Increases In The Upper Chamber
Forward Flow Valve Closed
Opening the Valve Manually
• Internal manual bleed
–
–
–
–
Turn the solenoid counter-clockwise ¼ turn
The upper chamber water exits through the exhaust port
The force below the diaphragm is now greater
The valve opens
Internal Manual Bleed Operation
Reverse Flow Valve
• How does the water enter the upper chamber?
– External tube
– Internal port
– Directly through the diaphragm
Reverse Flow Valve
• Directly through the diaphragm
– DV series
DV Series Valve
Reverse Flow Valve
• Internal port
– GB series
GB Series Valve
Reverse Flow Valve
• External tube
– EFB-CP series
EFB-CP Series Valve
Closing Speed
• The closing speed is controlled by using a fluid resistor
to regulate how fast water enters the upper chamber
• The solenoid port and exhaust port allow water to
escape faster than it can be replenished into the upper
chamber
Opening the Valve Automatically
• The controller sends 24 VAC to the solenoid
• The solenoid coil develops a magnetic field which lifts
the plunger
• The upper chamber water exits through the exhaust
port
• The force below the diaphragm is now greater
Opening the Valve Automatically
• Water Escapes From The Upper Chamber
Reverse Flow Valve Open
Closing The Valve
•
•
•
•
The controller stops sending 24 VAC
The plunger covers the exhaust port
Water is trapped in the upper chamber
The force increases above the diaphragm
Force Increases In The Upper Chamber
The Valve Closes
Opening the Valve Manually
• Internal manual bleed
–
–
–
–
Turn the solenoid counter-clockwise ¼ turn
The upper chamber water exits through the exhaust port
The force below the diaphragm is now greater
The valve opens
Internal Manual Bleed Operation
Opening the Valve Manually
• External manual bleed
– Turn the bleed screw counter-clockwise
– The upper chamber water “vents to atmosphere”
» Water escapes faster through the external bleed
– The force below the diaphragm is now greater
– The valve opens
External Manual Bleed Operation
Troubleshooting
• Check for the obvious
– Is the water turned on?
» Manually bleed several valves
– Is the valve receiving 24 VAC?
» Feel the solenoid for heat or vibration
• Defective controller or programming problem
Troubleshooting
• Valve not closing
– Seeping
• Valve not opening
Valve Is Not Closing
• Solenoid plunger stuck in the up position
– Dirt and debris
– Corrosion
Plunger Stuck In The Up Position
Valve Is Not Closing
• Diaphragm filter plugged
– No water can enter the upper chamber
Diaphragm Filter Plugged
Valve Is Not Closing
• Receiving voltage from the controller
– Defective controller
– Incorrect programming
Constant Voltage To The Solenoid
Valve Is Not Closing
• Debris under the diaphragm assembly
– Rocks and other debris
Debris Under The Diaphragm
Valve Is Not Closing
• Large hole in the diaphragm - Forward Flow
– Sufficient force cannot develop in the upper chamber
Large Hole In A Diaphragm - FF Valve
Valve Is Not Closing
• DV valve installed backwards
• The valve operates backwards
– When 24 VAC is applied, the valve closes
Valve Is Seeping
• Diaphragm seat damaged
Diaphragm Seat Damaged
Valve Is Seeping
• Solenoid seat damaged
Solenoid Seat Damaged
Valve Is Seeping
• Small hole in the diaphragm - Forward Flow
Small Hole In The Diaphragm - FF Valve
Valve Is Not Opening
• Valve is installed backwards
– All valve have arrows on them which indicates the
direction of water flow
Valve Is Not Opening
• Flow control tightened too far
– Water will pass through the exhaust port only
Flow Control Stem Too Tight
Valve Is Not Opening
• Solenoid defective
– Check the resistance of the field wires and the coil with a
multimeter
» The solenoid should be between 20 and 60 ohms
Valve Is Not Opening
• Solenoid plunger stuck in the down position
– Dirt and debris
– Corrosion
– Plunger spring installed incorrectly
Plunger Stuck In The Down Position
Valve Is Not Opening
• Plugged solenoid port
– Small rocks or sand
Plugged Solenoid Port
Valve Is Not Opening
• Plugged exhaust port
– Small rocks or sand
Plugged Exhaust Port
Valve Is Not Opening
• Large hole in the diaphragm - Reverse Flow
– Water will pass through the exhaust port only
Large Hole In The Diaphragm - RF Valve
Valve Is Not Opening Fully
• Small hole in the diaphragm - Reverse Flow
Vave Not Opening Fully - RF Valve