I’m just setting up my new OSPi and decided to test the voltage outputs prior to connecting my valves. When I look at the voltages (without anything connected) the OSPi outputs about 12 Volts when switched off and about 24 Volts when turned on. I would have expected to see 0 Volts when turned off, is this normal?
I then connected one of my stations along with the volt meter and it dropped to 0 Volts. When switched on, the valve turned on and everything worked fine, just wasn’t sure what was going on.
The first thing is to make sure your power adapter outputs AC voltage, not DC — especially if you are using your own adapter, it’s a common mistake to find a 24VDC adapter, since they are easier to find than AC adapters.
Next, if you have a AC adapter, when a zone is off, it’s common to see some stray voltage — the stray voltage should be gone when you have an actual solenoid connected.