Sprinkler Solenoid Resistance Diagnostic
Enter a power-off resistance reading to place the circuit in a useful fault range. The tool distinguishes an open circuit, likely short, high resistance, and a plausible reading—without pretending resistance alone proves the valve is good.
Turn controller power off. Disconnect at least one conductor so you are not measuring through the controller or parallel wiring. Never measure resistance on an energized circuit.
- Reference range
- 20–60 Ω
- Your reading
- 30.0 Ω
The resistance is plausible for this reference, so a dead short or fully open circuit is less likely. This does not prove the valve opens hydraulically or that voltage remains adequate under load.
What the reading can tell you
A resistance test checks the continuity of the electrical path at rest. It cannot show whether controller voltage collapses when the solenoid is energized, whether the plunger moves, or whether water reaches the valve inlet.
How to isolate the fault
- Switch controller power off and label the station conductor.
- Measure at the controller first. Then disconnect the coil at the valve box and measure the coil directly.
- If the coil is plausible but the full field circuit is high or open, inspect the cable and waterproof splices.
- If electrical checks pass, continue with the solenoid diagnostic guide instead of replacing parts by guesswork.