Zones won't activate

We recently installed the Rachio Gen 3 at our home, switching from a Hunter Pro C control panel that died. However, we couldn’t get any of the zones to come on during the test. We got an error that said “Rachio detected a fault in zone master valve…”

It has been a while since we ran the system, and we aren’t sure if this problem existed before installation the Gen 3 or is new.

Where do we begin with troubleshooting?

Thank you for your assistance!

Can you post a picture of how your Rachio is wired? Also, do you have a master valve?

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Thank you for your response. A pic of the Rachio wiring is below with the previous Hunter wiring.

I am not sure if we have a master valve.

@jim - The thick blue wire in the Rachio M terminal goes either to a master valve or a pump start relay (if there is a pump that supplies water to the irrigation system).

If there is a pump start relay in the system, some models pull too much amperage to turn on the pump and Rachio will report a zone fault in the master valve. If this is the case a low power (amp) pump start relay may be needed.

If the thick blue wire goes to a master valve (a sprinkler valve that shuts off the water to the rest of the irrigation system when it is not running), then the issue can be with the master valve or the valve on the first zone being run. I’d manually open the master valve (usually a bleed screw or turning the solenoid a quarter turn), disconnect the thick blue wire and see if the zones run.

Another test would be to disconnect the master and zone 1 wires and see if Rachio can run zone 1 with out any error (no water will come out). Then connect zone 1 to Rachio and run zone 1 again (again, no water will come out - unless the master valve has been manually opened). Then disconnect zone 1 and connect the M (thick blue wire) run zone 1 again (still no water should be expected). If no error messages have been generated on any of these tests then connect the M and zone 1 wires back and try to run zone 1. If an error message was generated then that is where the error domain is.

Additionally, one can measure the resistivity down the M and zone 1 lines and back to the C line with an ohm meter to see if there is a short in the line.

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Thank you so much for the help! We were able to locate the master valve tonight and tested the resistance between the common wire and all the zones. There was resistance on all. However, there was no resistance between the common wire and the master.

We were also able to manually turn on the master valve and manually turn on each of the four zones where we could find the solenoids.

Is there a reason there wouldn’t be resistance between the common and master? Once we figure that out, we will try the tests you mentioned with the Rachio controller.

Also, is there an easy way to locate the solenoid for the 5th zone? It is not on the schematic the installer left here at the house and grass has grown over the solenoids, making them difficult to find.

@Jim - with the master valve manually open and disconnecting the blue wire from the Rachio, the Rachio should be able to run all the zones.

Upon further review of the wiring, it looks like the prior setup had a wired rain sensor (two black wires) and a remote control unit (blue, red and white wires).

Rachio won’t support/use the remote control unit, so the small red and white wires in the 24 VAC - and + can be removed. I see the small blue wire doesn’t appear to be connected. (If that does go to a remote control unit).

The wired rain sensor should have one wire in S1 (or S2 - your choice) and the other wire in 24 VAC -.

See ->

As far as finding the fifth valve - do you have a metal detector? I’d try having the Rachio run the fifth zone and see where it is watering. Then I’d see where the nearest known valve is and walk from the nearest known valve via right angle path toward the fifth zone area to see if I could find it. One may need to call out an irrigation specialist to find it if necessary. If the Rachio runs the fifth zone with the master valve open, the it may not be necessary.

No resistivity between the thick blue wire (master valve) and the thick white wire means there’s not a circuit there. Not sure why that would cause a master valve zone fault. I might double check/redo the connection at the master valve. Use water tite wire nuts for that connection.

We got overrun by things tonight but will be running these tests tomorrow. Thank you!

Thank you for your patient help, @DLane. With your assistance, we figured out we have a bad master valve and will replace. You saved us some good bucks!

We may be back, we have a few more issues to work on but grateful to have this resource available :slight_smile:

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@DLane For the win, again!