Sub-Zero Code 30 U 00: Water Valve Open Circuit

Code 30 U 00 means the main control read an open circuit at the primary water inlet valve solenoid instead of the coil's normal resistance. Because it can no longer energize that valve, the unit stops filling for both the icemaker and the dispenser, so you lose water and ice together.

You can safely confirm the household water shutoff is fully open, check the supply line behind the unit for kinks, and power-cycle the unit. But because 30 U 00 is an electrical open at the inlet valve, diagnosing whether the coil or the harness has failed and replacing the valve is a job for a technician, since the water line is pressurized.

Once the failed inlet valve or its wiring is repaired, the open circuit clears, and the code drops out on its own after the control sees a normal coil reading. A power cycle (unplug or trip the breaker for a minute) clears the stored fault from service mode so you can confirm the repair held on the next fill cycle.

Cooling and food safety are not affected, so the unit is safe to run. The practical problem is no water fill: the icemaker will not produce ice and the dispenser will not deliver water until the inlet valve circuit is restored. There is no leak or electrical hazard from the open itself, but the fault will not self-correct.

The usual culprit is the water inlet valve with an open solenoid winding, or a corroded connector/chafed harness feeding it. Our diagnostic is a flat $89, applied toward the repair, and every repair carries a 365-day warranty. Call (650) 668-1554 for a quote on the valve replacement.

Code 30 U 00 is the main inlet valve that feeds the whole water circuit, so both ice and dispensed water stop. Code 30 U 10 is specifically the dispenser water valve, where ice often still works while only door-dispensed water fails. A technician confirms 30 U 00 by ohming the inlet valve solenoid and verifying continuity back to the board.