Strange voltage reading

I am still running my New Rachio 3 in simulation mode (no valve connected) so I can see what it predicts versus reality.

To be sure it was working, I decided to test the AC voltage on the Valve control terminal when in standby and when the controller activate the zone, an I am seeing something strange.

Even when no Zone is activated, the Voltmeter is reading 24V, when the Rachio activates the Zone, the reading goes up to 28V.
On my old controller, when a zone is not activated, the reading is zero…

To double check, I connected a small 24VAC LED across the common terminal and the Zone terminal, and when no zone is activated, the LED has a very faint illumination, and when I activate the Zone it lights up brightly.

It is like there is always some tension applied just with a faint current.

Is that Normal??

1 Like

It’s normal for there to be a small leakage current through the triac switch. If the valve were connected, the “off” voltage would be only a few millivolts. The old controller read zero because it used a mechanical relay.

If it concerns you, test with a valve connected, with a load resistance of a few thousand ohms, or use an old analog meter (with a pointer) that presents a heavier load.

1 Like

Thanks for confirming that it wont be a problem with the valve, I just wanted to make sure there was nothing wrong with the unit as I don’t plan to connect the valves for another few weeks.