Hayward's entry-level OnCommand automation controller comes with built-in support for 3 valve actuators: pool/spa suction and return valve, as well as a solar valve. It also has 4 high voltage relays, two of which I am using for the pump and the pool light. The third and fourth can be switched with the "AUX" buttons on the remote.
In order to add a fourth actuator for a water feature, I just installed an SPDT relay that I trigger with the AUX1 coil wires like others have done for their systems. Alas, I am having trouble finding a 24 VDC drop on the OnCommand's control board for the actuators load connection.
So here is my question: Can I add that load wire to the suction valve's actuator's load wire in parallel? This would be the wire that is hot when the suction valve is set to pool. The logic being, that I always would want the water feature to draw from the pool anyways, so it would be OK if the feature does not turn on when the suction valve is turned to spa. My concern is that if the latter is the case and the suction valve's actuator is switched to pool, both it and the water feature actuator would draw a current that would overload the components in that circuit.
FWIW, the OnCommand logic board has a single 3 A fuse for the actuators that seems to carry about 16 VDC, the 24 VDC "magically" appears after the small relays for the three built-in valve controls. As far as I can tell, there is only a small electronic element in line between the relay and the plug.
Any feedback or advice would be greatly appreciated. Worse comes to worse, I suppose I could add another 24 VDC power supply, but I would rather not.