Irritrol RD-900: Controller Clicks But No Zones Activate

All nine valves operate manually at the valve boxes, but nothing works from the controller. The display functions normally, programs can be set, but manual activation from the controller produces only clicking sounds with no water flow.

Systematic Voltage Testing

Since water reaches the valves (manual operation works), the issue is electrical. Follow this diagnostic sequence:

1. Test Controller Output

With a multimeter set to VAC, measure between terminal #1 and Common (C) while zone 1 is activated. You should see 22-26 VAC. If not, the controller or its transformer is faulty.

2. Test Voltage at the Valve

If controller output is good, measure at the zone 1 solenoid wires (disconnected from solenoid). Same 22-26 VAC expected. If voltage drops here, there's a wiring break or bad splice between controller and valve.

3. Test Solenoid and Diaphragm

If voltage is good at the valve, the solenoid or diaphragm is defective. Measure solenoid resistance (20-60 ohms). If resistance is good, replace the diaphragm.

Key Insight

Since no zones work from the controller, the problem is almost certainly at the controller output or the common wire path - not individual solenoids or diaphragms (all nine failing simultaneously is extremely unlikely).