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GCO 2431 Irrigation • Click here to return to Wildmon’s homepage 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