Tagged: motorized ball valve DC
September 13, 2016 at 4:26 pm #44059
has anyone made an adapter to drive DC motorized ball valves from open sprinklers 24ac outputs?
these valves have 3 wires and need 12 volts on one wire to open, and on the other wire to close.
We are working up an adapter board to do this, because solenoid valves clog easily in our application using irrigation water with fertilizer injected.
There are automatically closing valves but they are more expensive… though they have the advantage of closing without power.September 16, 2016 at 1:53 pm #44079
Do the ball valves have internal limit switches that stop the motor operation once in the closed/opened position?
You could drive from a 24VAC relay. On the normally closed relay contact drive the valve close wire and on the normally open relay contact drive the valve open wire.September 16, 2016 at 4:59 pm #44081
That’s a good idea, thanks!
Yes, they have limit switches. There are a bunch of kinds…
-two wire reverse polarity to open or close
-three wire, common and + to one ot open, + to the other to close
-two wire spring return – + to open, 0 to close. (more expensive but failsafe)
24vac dpdt relay driven by open sprinkler output, with a dc supply to drive the valves could be wired to any of these types.
Also open sprinkler DC would run the spring return type directly, I believe… but i would have to replace my ac units.
we will probably make up a relay board.
We might also add a fifth relay to drive a clean water flush valve to clear the fertilizer water from the plumbing between runs. it gets complicated!September 17, 2016 at 1:48 am #44083
That should be fine then with limits, I was just concerned if it didn’t have limits it would sit there humming away after its already on position.
You may be able to drive direct with the spring type if you use a bridge rectifier – take care to use fuses. I’m driving a 24VDC relay from 24VAC open sprinkler through a bridge rectifier. I’m only doing that as I had a 24VDC and not a 25VAC relay on hand 🙂 (And the bridge rectifier came from old dead computer power supply)April 28, 2019 at 1:41 am #59981
For those like me from the future internet, I’d like to re-raise the original question given the update to OpenSprinkler since, such as the DC controller and Latching versions.
Specifically, as I’m automating a solar powered off the grid setup, I’d love to use motorized ball valves with OS. The two-wire auto-return in theory should work with the standard DC OS version, as these spring to close when de-energized. I’m curious if the DC latch version works with 3-wire valves, which require a change in polarity to re-close? It may however be the case that latch control is too different in the specifics. I’d be interested to hear what capabilities around motorized ball values now exist.May 16, 2019 at 4:34 am #60410
Regarding the 3-wire type: DC Latch version cannot directly operate it — if you use DC Latch version, it should work with the 2-wire reverse polarity type, with some minor modifications of the firmware. Instead, 3-wire type has a common cathode, and two anodes one for opening the valve, one for closing the valve. So it can work with the OS DC version, with a slight hardware modification. Specifically, OS DC uses common anode (the common wire is the positive), and each zone is a cathode switched by the control signal. This logic needs to be flipped via a transistor per zone so that each zone becomes a switched anode. This way, a 3-wire motorized ball valve will take over 2 zones, one for opening it, one for closing it.August 3, 2020 at 2:07 am #67698
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