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I need to split an existing sprinkler zone into two zones. The issue I have is I cannot remove the valve that currently controls the flow. So, I need to have the system turn on both the original "main" valve and one of the new.

For example. Current zone 5 becomes zones 5 and 6. When the controller kicks on zone 5 or 6, the original valve also opens.

All I can come up with is maybe using 2 relays to make an logical OR circuit or maybe diodes to keep all of the lines separate so they could be tied together....

I am wondering what the best way to wire this up would be? The system is 24 VAC.

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Have you considered hard-wiring the original (upstream) valve so that it's open all the time? – Nick Alexeev Aug 17 '12 at 2:07
Do you have an extra zone on your controller? Use zone 7 to control the "master" valve and just be sure to program it to run concurrently with 5 or 6. Alternately, most such valves can be manually turned on. Some leak in this mode, some don't. If yours is leak-free, just force it on manually. – HikeOnPast Aug 17 '12 at 4:01
I have considered it, but figured keeping the valve open all the time with the solenoid would not last. I am not sure if these can be operated manually, but will check. I will also check if I can run multiple zones at the same time. Any idea on how to make a circuit? – RShearer Aug 17 '12 at 23:48

1 Answer

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Since this sounde like a one-off and therefore a few $ more once shouldn't matter that much, two relays would solve this problem easily. Get two DPST (minimum) relays with 24 VAC coils. The existing drive circuitry turns on the relays instead of the valves, which will be indistinguishable to it. Each relay then turns on its zone valve with one pole and the existing common valve with the other pole. In other words, the common valve will be separately enabled if either of the new zone valves are on. All this will happen transparently to the controller if hooked up right. The controller will only see a additional zone.

This is not cheap or elegant, but just two relays and a few wires and you're done.

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