Near Intersection of I-35 & I-90 Southern Mn. | I believe you should be able to use the 3 wire valves instead of the more expensive 4 wire with indicator type from CIH.
Are you certain that the 4th wire is a On/Off position indicator? It may be. I have seen some valves that way. On the other hand I have seen valves that use 4 wires where the 4th wire can be used to cycle the valves. Then there are also valves that use a polarity reversing scheme which generally only have 3 wires.
1) let's suppose you are correct and the system allows the 4th wire to be an indicator. Having an indicator can be useful but may not be required for the valve to work. That 4th wire usually just goes to ground when the valve is open. That wire can be used as a ground for an indicator light.
In other words you would use the constant hot (always 12V), constant ground (always ground) and the trigger wire that is 12V when the valve should open and remain open as long as 12v is present on it but close when the 12V is not present. The 4th feedback wire in the planter harness would not be connected to anything. If you loop it back to ground, the valve would probably operate fine but the indicator might always be lit whether the valve was open or closed. Having the indicator lit all the time is probably acceptable but serves no useful purpose.
2) let's consider the other style valve wiring I have seen where all four wires are used to operate the valve but there is no provision for a feedback indicator. These valves need a 12V constant source, a ground for the motor, a trigger wire that goes to 12V when the valve should be open and the 4th wire is a ground for the internal relay. These valves can be wired to a 3 wire harness by splitting the ground and connecting it to both the motor ground and the relay ground. Other 3 wire valves wire the two grounds together internally. I have seen many KZ valves that use that setup.
You may wonder why the relay ground and the motor ground are not always wired together internally (in most brands they are). By having the relay ground separate it would be possible to change the status of the valve (open or closed) either by switching the 12V trigger wire OR the relay ground wire since the relay would need to have a complete circuit to cause the valve to open.
I have seen a few setups where this was used. The 12V trigger wire for each valve was controlled by a switch box or controller in the tractor. An implement switch on the implement was wired so that when the implement was lowered, the switch completed the ground circuit in each valve's internal relay then the valve would open if that section switch was ON in the tractor. This eliminated the need to run an implement switch branch all the way back to the tractor. Some older Hiniker systems used that approach. If an implement switch was not used, that branch was just attached to ground.
So I'm guessing you should be able to use a valve that is wired with 3 wires even though the system is capable of using 4 by simply not using the feedback status wire. Avoid the valves that are the polarity reversing type. They could be used but an external relay box would be needed which adds to the complexity a bit.
Edited by tedbear 11/23/2024 08:31
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CIH 1255 fertilizer
