Unstable current from rachio 3 into the solenoid in the valve

I am currently setting up rachio 3 system for my rainbird anti-siphon valves. After i finished wiring up rachio 3 to the valves and turned on the valve using the app, i noticed a solenoid was turning on and off sporadically. When i manually turn on the valve it works fine and my water pressure is around 75psi (municipal water without a master pump). So i checked the current that goes into the solenoid and noticed that it fluctuates when the symptom occurs (constant current then it dips low when the problem occurs). So, i think the unstable current from rachio device is causing the solenoid to open/close sporadically.

Now, i am not sure why the current would fluctuate like this. I tried to reset the device, it worked fine for couple runs then it showed up again. Sometimes it runs ok, sometimes it fluctuates, and can’t figure out why it is happening and how to fix it.

Thanks for your help in advance.

IMO the most likely cause is a problem with the field wiring. To test for this, monitor the voltage at the controller between the zone terminal and common. When the problem occurs, if it’s a wiring issue, the voltage will remain high or increase slightly. If it’s a controller issue, it will dip low. (There is a small possibility of an intermittent partial short in the field wiring, in which case current measured at the zone terminal will increase.)

If you determine that it’s controller related, check the output voltage of the transformer. If that remains stable, try to get a warranty replacement. If it dips, check the voltage at the transformer input; there may be a problem with the outlet wiring, breaker feeding it, etc.


hi Stewart,

I followed your advice and monitor the current coming out of the zone terminal. the current remains high (~0.2A)when there’s no problem. but when there’s a problem it fluctuate from 0 to 0.2A sporadically.

To further troubleshoot, check voltage between the zone terminal and common.

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You did not follow his advice. He said to monitor the zone output’s voltage. We know the current is dropping. The question is why? By measuring the voltage across the zone output and common you can begin to get a clue. As @Stewart wrote: If the voltage rises when the solenoid turns off: It’s a “field” problem (wiring or solenoid). If the voltage drops when the solenoid turns off: It’s a controller zone output problem.

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the voltage stays around 27V when it runs smoothly. when the symptom occurs it starts to fluctuate. unfortunately, I wasn’t able to pinpoint whether the voltage goes down to 0V or to OVL, because PVC pipe started to leak and I had to stop and shut off the valve. but I remember reading 7.7V, 1.3V, 0.6V, 0.1V so I supposed the voltage dropped?? I mean… It was turning on and off so fast that the multimeter reading wasn’t able to keep up with it. at least, I didn’t see a voltage reading higher than 27V.

when solenoid was turning on/off so fast like this, the whole unit started to jerk quite a bit and I think it may have put too much stress onto the PVC joint and break. i should have secured the system before the run, but oh well… that’s another story…

Anyhow, I reached out the Rachio technical support and they ran the unit remotely and saw the same problem. they think it maybe the physical defect in the unit and will send me the new unit to try. I hope it solves the problem. In the meantime, I am going to replace the cracked PVC joint.

Thank you all for your support and I will update the result once I receive the new unit.