Confusing Wiring Setup from Previous Home Owner

I recently moved to a new property with an 8 zone irrigation system. Zones 1-7 functioned properly on the old Rain Bird controller. I could not get Zone 8 to function and I can visually see sprinkler heads that have not turned on. I ended up upgrading to a Rachio 3 and intended to figure this out on my own. Zone 8 still does not function.

My before and after setup is as follows:

The wiring is confusing.

There are two black lines with the colored wires within. There’s also what appears to be a Hunter Rain Sensor on the roof with 3 lines (one not terminated).

Black grouping line one

  • Red = Zone 1
  • Blue = Zone 2
  • Green = Zone 3
  • Yellow = Zone 4
  • Brown = Zone 5
  • Black = Zone 6
  • White = Zone 8

Black grouping line two

  • Red = Connected to rain sensor
  • Blue = Zone 7
  • Green = Not stripped for termination
  • White = Not stripped for termination

Rain Sensor

  • One line to the common
  • One line to grouping line two’s red line
  • One Not stripped for termination

Any thoughts on how to set this up properly?

@Arin - my guess is that there is a basic wired rain sensor. So take the red wire from black grouping line two and move it from the rain sensor to a Rachio C terminal. Take the wire from the rain sensor that is currently in the Rachio C terminal and put it in the Rachio S1 terminal and set that sensor port to a rain senor. Take the rain sensor wire that was connected to the red wire in black grouping line two and put it in the 24 VAC - terminal.

For zone 8 - get a multi-meter and measure the resistivity when disconnected from the Rachio down the white zone line and back to the red common line. It should be around 30 ohms. If there is no reading, then there is a break in the line. See if the valve box for this zone can be found and check the connections there.

Thank you. I’ll give that a shot!

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Red wire to the common worked.

Rain sensor wired up (no idea if it works, can I verify?

Zone 8 still dead. I’ll give the volt meter a go.

I need to keep searching for the valve control box. I spend a hour or so looking for it on the property. It’s on an acre, and my guess is the box is buried under pine straw somewhere. I was probing the ground like I was sweeping for mines for over an hour with no luck! Haha.

With the volt meter I tried to measure resistance, but maybe I’m not doing it right. On zone 1 (working) the values jumped all over the place. On zone 8 (not working) I got the same behavior.

@Arin - finding valve boxes can be fun. They will typically be laid out in a grid due to piping, so if know where other valve boxes are and the sprinkler heads work in 90 degree offsets to connect the dots.

Regarding the resistivity measurments, they should be relatively stable. I recommend taking at least one side out of the Rachio terminal to prevent measuring back through the device and make sure there is a good connection to the other side if it is still in the Rachio wiring block.

On the rain sensor - depending on the type there may be a button that can be pressed to test the switch. One can also dump a cup of water on it - slowly so it will soak it up to test - but it will need to dry out before the system will water again (unless you take it out of the app).

I used this to help find my wires: Kolsol Underground Wire Locator…

It wasn’t a panacea, as parallel lines tend to inductively pick up the signal. If you can find the box with the valve for this sprinkler, that’s the best place to start with this tool. I had one box which was covered in grass, and just pushing a screwdriver into the ground was the most help in finding the box once I dug up one of the sprinkler heads to find the supply pipes. I had to add a new wire, as some time in the past, they drove 4 valves with 3 wires, and one of them broke I had 7 zones driving 8 valves and one of the zones didn’t work, and I’ve added a new zone for foundation watering, and would like to add 3 more, two to separate the parkways (corner lot) from the other zones, and one more foundation watering zone (it’s a North Texas thing). Glad I got the 12 zone system.

I’m going to pick this up. Where should I connect the leads? One on common, and the other on the zone that doesn’t work?

One lead connects to the wire of interest, the other to earth, as stick a long screwdriver into the dirt and connect the other lead to the screwdriver. There is some getting used to the detector, and both pieces use 9v batteries faster than you would expect. The detector has a wire with a sensor on the bottom, and you swing it like a pendulum perpendicular to where you expect the wire. When it’s right over the wire, it makes no noise, loud when slightly off center, and quieter the further you get away from the wire. It could help to put 5 feet or so of wire on the ground, and practice when you can see the wire and listen to the sound. It works best when not close to the where the signal is induced. One problem is that the neutral wire will be running next to the supply wire, and it will inductively absorb some of the signal, which may make it hard to find the break, but it will at least help find the path of the cable.