Rain Dial Controller Outputting Only 15V: Isolate Controller or Field Wiring Fault

Rain Dial Sends 15 VAC to Solenoids; Transformer Measures 24 VAC

1. Disconnect the field wire from terminal 1 and the common wire from terminal C.
2. Activate zone 1 and measure voltage between terminal 1 and C.
3. 24 VAC: Field wiring has a voltage drop (high resistance, bad splice).
4. 15 VAC: Controller output stage is bad—replace circuit board or entire controller.