A "Zone Fault" notification detects electrical faults, which are typically caused by wiring issues. In this article, you will find reasons for Zone faults and how to troubleshoot.
How To Fix a Fault
Some common reasons for faults include:
- Worn or defective solenoid;
- Damaged or faulty wiring;
- Poor wire connections and/or improper wire installation
When the controller experiences a fault on a zone (or the master valve) we:
Restart the controller.
Send a push notification to your mobile phone.
Add an event to your History feed.
The controller History feed will include the zone number (or master valve) that faulted and the time of day the fault occurred.
Continue attempting to run the zone as scheduled, although the zone may not actually water.
A fault will restart the controller but will not complete the schedule after the affected zone is identified. The detection feature is not available on Generation 1 controllers.
Isolate the fault
Remove the wire from the zone terminal identified from the controller. Manually run a 2 minute test schedule for all zones. If the fault is not detected in the activity feed, the problem is with the solenoid or field wiring.
Check the solenoid
Check the voltage to the nonworking zone using a multimeter.
Check voltage at the controller
Using the AC voltage reading on your volt meter, touch one probe to the station terminal you wish to test and the other probe to the C or COM terminal while the station is activated. Typically, it does not matter which of the two colored probes goes where, but for consistency purposes use the black probe for the C terminal and the red probe for the station terminal.
Checking voltage at the solenoid
Use the same AC voltage reading on your volt meter as used on the controller. It is no coincidence that the solenoid has two wires and the controller had two screw terminals for you to test. Solenoids have two wires, one for the COMMON wire and one for the station's power wire. Typically COMMON wires are shared throughout irrigation systems to save on wire. Place either probe from the volt meter on what's presumably the COMMON wire at the valve manifold, place the other probe on the solenoids power wire. With the station activated you should have 24-28VAC.
Test the resistance “ohms” between the common terminal and the nonworking zone. Turn off the system, turn the multimeter to test for ohms (Ω) or (~), and place the leads on the common terminal and zone terminal. This simple test will let you identify if there is a shorted solenoid or a cut wire going to the valve. In either case, the valve will fail to open when the proper voltage is sent to it from the irrigation controller. You should get a reading from 20-60 Ω; every manufacture’s valves will have a slightly different reading. If the ohms fall below the required amount (20 Ω), the solenoid that operates the control valve for that zone is defective and needs to be replaced. The defective solenoid will be connected to the same color wire as the zone wire at the controller. Conversely, any reading above 60 Ω is indicative of a wiring problem. This usually occurs due to the age of the valve, electrical surge or cut wire.
If you get a reading of zero or offline (OL), this usually indicates a wire has been cut between the irrigation controller and the zone. If you receive the same OL (offline) reading for all the zones, this may indicate the common wire has been cut as all the zones share this wire. Remember to test Zone 1, as an OL reading for indicated the common has been cut between the controller and the first zone. To make repairs in this situation you may need to run a new common or track down the break with a fault locator.
Although valves themselves rarely need to be replaced, solenoids do occasionally fail. Replacing them is quick and easy. Remember to unplug the controller and make sure the valves on the backflow device are turned off. Inside the control valve box, remove the wire connectors and disconnect the two wires on the defective solenoid from the common and field wires. Turn the solenoid counterclockwise to unscrew it from the valve. Water will slowly seep out of the valve opening, even with the water turned off.
Place a new solenoid in the valve and turn it until it's finger-tight. Twist the ends of the new solenoid wires onto the same common and field wires that the old solenoid was attached to. It doesn't matter which solenoid wire goes to the common and which one goes to the field wire. Twist a new waterproof wire connector over each connection. To make waterproof connections, use a silicone-filled “direct bury” connector available at home centers.
Check the wiring
If the ohms reading between the common terminal and fault zone terminal is too high (above 60 Ω), the problem is a severed or bad wire to the control valve. If only one zone isn't working, the field wire is damaged. If none of the zones in a control valve box is working, the common wire is damaged, although the field wires could also be bad.
To find a bad wire, bypass the wire by temporarily substituting a temporary wire for the original that you run above ground. Make the wire connections with the controller turned off. Then turn the controller back on. Test the field wire first. If the zone turns on, the old field wire is bad. Replace it with an 18-gauge wire rated for underground burial. Bury the wire at least 8 in. underground. Follow the same procedure to test the common wire.
Find a Rachio Pro
Need help fixing a zone fault? Click the button below to find a local Rachio Pro!