When two or more controllers are connected to a master valve or pump circuit there are both potential and inevitable problems, especially during maintenance and repair of the controllers. Adding a pump relay to each controller solves some problems but ISOLATOR offers double protection by locking out all controllers except one, and for about the same price. Below are three common problems of interconnected controllers
FEEDBACK: When the first controller begins a cycle, it sends power to the pump or master valve which is also connected to the other controllers on the irrigation system. Some controllers exhibit strange behavior( like starting a cycle) when external power is applied to their Pump/Master Valve terminal.
POLARITY: When an irrigation controller is removed for repair, the transformer wires can easily be reversed when it is reinstalled. It's common terminal will be a 24 volt difference from the other common wires.
PHASING: Phasing problems occur when controllers are on different "legs" of a 240 volt utility service. The 120 volt supply to the controllers is out of phase. ISOLATOR provides the only method of interconnecting these controllers to operate a pump or master valve.
If you have these problems you need ISOLATOR. Add to the mix several brands of controllers, both mechanical and digital, old and new, then you really need ISOLATOR!