My current irrigation controller is a 15 year old Hunter Pro-C with 14 zones. It is still working but I am planning to replace it this spring with an OSV3.0 AC with an extender. I am familiar with OS from my last house.
The company that services my system prefers their Hunter remote control for service over the use of a phone due to the obvious environmental issues. The OS advantages of network access, the phone app and the API for automation integration are important to me.
Is there a way we can both have what we want? Is there a way I can connect both controllers to the zones and switch between them when the service people need access?
I would be careful putting two controllers in parallel. The reason is that the internal mechanism of how each controller switches a solenoid can be different, and if both try to turn on the same solenoid at the same time it might result in shorting. I think if the following two conditions are satisfied it should be safe:
1. each controller uses its own power supply, no sharing of the same power supply
2. it’s guaranteed that the two controllers won’t turn on the same solenoid at the same time.
In addition to using separate power supplies for each controller, I can insure that only one controller is powered at a time.
To implement the parallel wiring, I will make a zone connection strip, separate from each controller and then connect the zones from each controller to the strip. This will make it easier to disconnect either controller if needed.
The irrigation company is going to be happy 🙂