- This topic has 4 replies, 2 voices, and was last updated 7 hours, 29 minutes ago by
.
-
Posts
-
Hey,
I just installed my brand new OSPi. It is replacing a working OpenSprinkler 3.0. I am running firmware 2.2.1(1). My zones aren’t turning off with the OSPi. I’m manually turning on a zone for 3 minutes, the zone turns on and runs, the timer stops in the app after 3 minutes and shows the zone off, but the water is still running. In order to get the water to stop running I have to pull the 24 volt power. The water stays stopped when the 24 volt power is reapplied until the next time I manually turn on a zone then the problem repeats.
The most common cause for this symptom is using a power adapter that outputs DC instead of AC. You should check the label of the power adapter, does it have a flat line after ’24V’. If so that’s a DC power adapter.
It’s a DC adapter. I had it from another project that went nowhere and was excited I could finally put it to use. This is what I get for not just buying a complete kit from Ray. Long term do I have to worry about having caused damage to the OSPi?
Most likely it won’t damage OSPi. Remember, 24VAC’s peak voltage is much higher (1.414 times) than 24VDC, so if the circuit can handle 24VAC, it can handle 24VDC. What would be more of concern though, is your solenoid valves — because of the way solenoid valves work, the current running through them will be way higher under DC than under AC of the same rated RMS voltage. This is explained in my article here:
https://rayshobby.net/wordpress/understanding-24vac-sprinkler-valves/
So the short story is: don’t use 24DC on 24VAC valves, otherwise the valves may burn out prematurely.As to why the valves would only open but not close: that has to do with how triac (AC transistor) works. To turn off, they need a zero-crossing, which happens quickly with AC. On the contrary, with DC, there is no zero-crossing, so once on, a triac will not be able to turn off, even if the gate current is removed.
Phew. Good news. I was more worried about damage/weakened components that will haunt me in the future as a result of the short time I had the DC power supply on there. As soon as you pointed out I had the wrong adapter I immediately unplugged it so my exposure is limited. I grabbed a 24 VAC adapter from a local hardware store tonight and the OSPi is working as expected. Thank you for your help with this Ray.
- You must be logged in to reply to this topic.