Near Intersection of I-35 & I-90 Southern Mn. | Yes, it would.
Here is a bit more, maybe more than you want: The Fast Close valve uses 4 wires. The old fashioned reliable standard valve uses only two.
The standard valve is like the butterfly valve as used on many sprayers but instead of a butterfly valve, a ball valve is used which is necessary for NH3. This valve can be used for regular liquids in place of a butterfly valve. Since its motor is geared down considerably, The Green and Yellow Increase/Decrease pair can supply enough current to nudge the valve slightly open or slightly closed. In normal operation this valve does not move when application is stopped. Another valve or valves handle that task.
Later in history, Raven came out with a Fast Close valve. The only purpose of a Fast Close valve rather than the traditional standard control valve and separate ON/OFF valve is to save money.
This valve is straddled with the job of closing quickly when application is not desired. This means the motor can not be geared down. When application resumes, the system must ramp open the valve until the target rate is exceeded and then back down a bit. With speed fluctuations throughout the field or rate changes, the valve must make minor adjustments.
Because the motor cannot be geared down, the Green/Yellow pair of wires cannot handle the electrical load. This is why a constant 12VDC and Ground wires are present. The Green/Yellow pair convey the controllers intentions to an internal circuit board which does the actual work of running the motor from the 12V constant and ground wires.
But back to your question. With a Fast Close valve, the controller set to Fast Close, the system will send a Full Decrease signal on the Green/Yellow pair to output the correct polarity and close the valve while the Master switch is OFF. The controller does not "know" when the valve is fully closed so it continues to keep sending the close polarity. The valve itself has a closed limit switch that stops the rotation. Likewise there is a fully open limit switch to stop the motor when the valve is fully open.
When I worked as a Tech, I would install Increase/Decrease LEDs beside the INC/DEC switch for customers on their 440/450 controllers if they desired. This was simply a green and a red LED that were wired across the Green/Yellow Increase/Decrease pair of wires.
This would give the operator visual confirmation of the control valve circuitry. With a Fast Close Valve set in Fast Close, with the Master OFF, the red LED would light showing the controller was sending out the correct polarity to reduce and eventually close the valve. Even when the close limit was reached, the red LED remained ON.
When the Master was turned ON, the Green LED would blink showing that the controller was opening the valve to a point where the target rate was exceeded and then a couple of red blinks to show that it had to back down a bit. If the target rate could not be attained, the green LED would remain ON and eventually a warning would appear indicated a rate problem.
This is part of the reason that Fast Close valves can be difficult to work with. For low rates, it is difficult for the valve to move just a tiny bit. The operation seems foreign to most operators and is thus difficult for them to troubleshoot.
Edited by tedbear 6/28/2025 09:44
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Raven Fast Valve?
