Explanation:
The controller has detected a short circuit on the master valve (MV1 = Master Valve 1, MV2 = Master Valve 2). This occurs when the load on the master valve circuit exceeds the skip current threshold, which is set to 1.5 amps (1500 milliamps) by default in the advanced menu. If this happens, the controller will not activate the master valve, and all zones dependent on it will not irrigate. However, once the current returns to a normal level, the fault will be cleared automatically.
Resolution:
A short circuit is usually caused by a faulty valve solenoid. Begin by testing the solenoid itself. You may also need to inspect the wiring between the controller and the solenoid.
You can test the valve circuit using a the controller's built in milliamp meter or an electrical multimeter on the ohms (Ω) setting (see here for a tutorial on testing ohms). A typical, healthy reading is between 200-350 mA and 20-60 ohms.
- A resistance reading below 12 ohms may cause the fuse to blow.
- A reading under 20 ohms indicates an issue with the wiring, which may require inspecting for wire damage or broken connections in the valve box.
If the multimeter shows a resistance greater than 20 ohms but the short circuit error persists, it’s likely that the solenoid needs replacement.
You can also adjust the current threshold before the fault is triggered by modifying the "SKIP CUR" setting in the advanced menu. To do this:
- Turn the dial to the Advanced Menu.
- Scroll to "SKIP CUR" and press the next button.
- Use the up and down buttons to set the desired threshold between 1.0 amps (1000 milliamps) and 2.5 amps (2500 milliamps).
Note: The controller has a 1.0 amp slow-blow fuse, and drawing more than 1 amp for extended periods can blow the fuse.
Once the issue has been resolved, manually clear the fault and run the program again to confirm the fix.