How to Diagnose a Bad Water Inlet Valve

A properly working water inlet valve is essential for consistent ice production. When this valve fails, it can prevent water from filling the machine or cause overfilling and leaks. Diagnosing a bad valve is straightforward if you know what to look for.

The first step is to check the water supply. Make sure the water line is open and that the machine is getting at least 20 PSI of pressure. It’s also common for the inlet screen to become clogged with debris or mineral buildup, which can restrict flow and cause the same symptoms as a bad valve. Cleaning or replacing the screen is often a quick fix.

Next, listen for the valve during the fill cycle. You should hear a click or a light humming sound as it activates. If there’s no sound, the valve might not be receiving power or the solenoid inside has failed. To confirm, use a multimeter to test for voltage at the valve coil during the fill cycle. You should see around 110–120 volts (or 220 volts on some models). If voltage is present but no water flows, the valve is defective. If there’s no voltage at all, the issue is likely with the control board, float switch, or wiring rather than the valve itself.

Another common sign of a failing valve is water leaking or dripping when the machine is off. This means the valve is stuck open and allowing water to pass through continuously. Even a small drip can cause ice overproduction or freeze-ups inside the bin.

You can also test the valve’s solenoid coil for resistance. With the power disconnected, use a multimeter to measure across the coil terminals. Most water inlet valves should read between 200 and 500 ohms, though exact specs vary by brand. If your reading is far outside that range—or if the coil is open (infinite resistance)—the valve should be replaced.

If the valve fails any of these checks, replacement is the best solution. Always use a genuine OEM or factory-approved valve to ensure proper flow rate, fill timing, and ice quality. Before testing or replacing any components, disconnect both power and water supply for safety.

A well-functioning water inlet valve ensures your ice machine performs efficiently and consistently—helping you avoid downtime, poor ice quality, or costly repairs down the line.