Help with Wiring

I actually have a Orbit Water Master 4 zones and I want to replace it with a Rochio 8 zones sprinkler but I just have some doubts with the right side wiring. I am attaching a picture of the current Orbit connections.
Could anybody help me with the new connections to Rochio sprinkler?

Hi @JMC1018!

For the right side of the wiring, I am struggling a bit with what is going where in the photo, however I can tell you what wires from each terminal will go where! Anything in COM1 or COM2 will go into a “C” terminal on your Rachio controller. Anything in the 24VAC terminals are actually not needed for your controller, and will not be used. Let me know if that clears things up, and if there is anything else I can help with!

McKynzee :rachio:


@JMC1018 - To add to what @mckynzee said - be sure to take some tape and label all the wires as it looks like there are multiple black and red wires - although they are different sizes.

I can’t tell if some of the wiring is coming down from the top or if all of the wires are actually in connections, similar to McKynzee.

It doesn’t look like you have anything connected to the Pump terminal. If a wire is connected to the Pump terminal it would go to the M terminal on the Rahcio unit.

And for completeness, the left side can go 1 to 1, 2 to 2, etc. on the Rachio terminals.

Oh, and I didn’t see a port for a rain sensor. Do you have a rain sensor and is it in-line with the common wire?


Thanks for the help. This was already installed when I bought my house so I have to see where those red wires come from.They are wired in the 24vac terminals for some reason.

I do not have a rain sensor.

@JMC1018 - those red wires in the 24VAC terminals power the unit. I was just saying you won’t need those in the future and the transformer will still be eating electricity if it is left plugged in somewhere.


It needs both the red and the black? I know the black goes to the transformer. Just not sure where the red is coming from

Just an individual trying to help. If you are unsure of below, suggest you get with someone with a little bit of electrical knowledge to help you.

Wires going to terminal 1, 2, 3, 4 are your valves for you sprinkler zones. Label and mark them 1, 2, 3, 4.

Cannot tell from the picture, but you should have one wire going to either COM1 or COM2 (looks like COM2). This is your common wire for all valves.

All wires going to 24VAC are not needed with your new controller. BUT it looks like you have 2 wires (one black and one red) going to each of the 24VAC terminals. Since you do not know where the red wires go (on the 24VAC connections) someone may have used this old controller as a junction to supply some other 24VAC device. Again none of this is needed for your controller, but unless you can determine where these red wires go, I would suggest you just use a wire nut to tie the red and black wires together that go to the same 24VAC terminal. So you would have two wire nuts one with a red and black wire and a second with a red and black wire connected.

For your controller, just connect wires 1-4 to terminal 1-4 and the COMM2 wire to the C terminal.

Hope that helps.

You are correct there is a wire in COM2.

It looks like the red wires are leading out to the vales.

@JCM1018 - I’d be curious as where those two red wires are going. I’m wondering if this is to a master valve that is powered open all the time? I couldn’t tell before, but if the big black wire pair comes from the transformer and is in the 24VAC then @tomlay 's suggestion of wire nutting the black and red wires together to keep the power going would work.

Assuming the load isn’t too much and that it only needs to be powered when the sprinklers are running, one red wire could go in the M(aster valve/pump) terminal and the other in the other C(ommon) terminal. One would also need to configure the Rachio to activate the master valve/pump option in the application. This would enable you to remove the old transformer and save wear on what ever is being activated by the circuit.

Now if something is just “borrowing” 24VAC to power something beside a part of the sprinkler system, then the wire nut solution is it.

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Would suggest that BEFORE you attach the red 24vac wires anywhere else, disconnect them and measure voltage (both AC and DC).If you do not read any voltage then you should be OK to experiment with them.

I agree with @DLane they are probably your master valve which could be configured as part of your new controller.

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@tomlay Each is going to the wires that go out to the vavles in the outdoor valve box. Does that make a difference

Probably a master valve as @DLane suggest and you can incorporate with your new Rachio controller (which I love btw) as it has a connection for a master valve. Best would be if you could find the valve (probably in an underground box close to your water supply) or find out from the previous owner. Would hate to advise you do something that messed up your new controller. But really feel that it is a master valve. I am just suggesting you be cautious.

You could start by removing one red wire from your current controller. Try to manually water a zone. IF it did not run, then this is almost certainly a master valve. Reconnect it and try again. If now it runs, I would say the two red wires run a master valve and you use with the new controller as it has a connection for a master valve.

So I would hook one to the M and the other to one of the common terminals?

I “think” there is a common terminal next to the M terminal and yes you would connect there. Doesn’t make any difference which one goes to M vs comm.

Also when you set up the software you have to tell the controller you have a master valve.

I do not see a master valve in this wiring set up.

Yellow tabs: I see transformer power to the controller with the black wires. I see power for the sensor with the two red wires. Wireless sensor setup.
COM2: Brown sensor wire. The white sensor wire connected to the common in the wire nut at bottom of pic.
Zone 1,2,3,4: Station/valve wires

@Sprinklerman So where would I hook up the red wires?

I would suggest to start you just wire nut the red wires to the black ones (one red to one black, two connections). Get the unit working then come back to these. Solve one problem at a time.

@Sprinklerman the thinking is these red wires are a master valve since the go out to the valve box no rain sensor. But either way, suggest starting out with them “hard wired” in to get things going.

Can you take a picture of where the COM2 wire is going and the wires in the orange wire nut?

Also, take a picture of the valve boxes with the red wires from the controller.

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Looks like its hooked up to the non working rain sensor. Seems straight forward now. Should have undone the tape when I first took the pic so there was no confusion… Thanks for all the help!!


@JMC1018 Glad to hear it’s all worked out! Enjoy the new controller!

McKynzee :rachio: