OpenSprinkler › Forums › Hardware Questions › Running Opensprinkler in Parallel with existing controller? › Re: Re: Running Opensprinkler in Parallel with existing controll
Without knowing the internal circuitry of your manual controller, it’s hard to tell. For example, on some controllers the COM wire is the logic ground of the circuit, while on OpenSprinkler it’s not. If you try to connect the two in parallel without knowing these details, it may directly short the sprinkler transformer. So unless if you are confident about how the manual controller works internally, I don’t recommend connecting them in parallel.