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Error code reference

Sub-Zero Refrigerator Error Code 30 U 30

Water valve solenoid energized for more than 35 seconds; icemaker system disabled.

Sub-Zero codesSub-Zero refrigerator codes

Water valve solenoid energized for more than 35 seconds; icemaker system disabled.

First step from the service manual

Check water valve solenoid (160-165 ohms), flow meter, and water supply. Correct problem and press ALARM key for 15 seconds.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What 30 U 30 means on a Sub-Zero refrigerator

Error code 30 U 30 on a Sub-Zero refrigerator indicates that the water valve solenoid remained energized for more than 35 consecutive seconds during an icemaker fill cycle. Under normal operation, the water valve solenoid opens briefly to deliver a measured amount of water to the ice mold, then closes once the flow meter confirms the correct volume has passed through. When the control detects the solenoid has been held open beyond the 35-second threshold without the flow meter signaling completion, it disables the entire icemaker system and triggers this alert to prevent flooding or continuous water flow.

The water valve solenoid itself should measure between 160 and 165 ohms of resistance. A reading significantly outside this range points to a failed solenoid coil that may be drawing excessive current or failing to fully open, causing the control board to keep the circuit energized in an attempt to initiate water flow. The flow meter is equally important in this fault scenario: if the meter is not registering water movement due to a stuck or dirty turbine, the control cannot confirm delivery and will keep the solenoid open indefinitely until the timeout triggers.

Water supply conditions are the third major variable. Insufficient line pressure or a kinked supply line can restrict flow to a point where the solenoid stays open far longer than intended. After identifying and correcting the root cause, the icemaker system will not resume automatically. The technician must press and hold the ALARM key for 15 seconds to clear the fault and re-enable the icemaker.

Source: manufacturer service documentation.

Common causes of 30 U 30

  1. 01

    Low or no water supply pressure

    Wiring / connection

    Insufficient household water pressure or a kinked, closed, or partially obstructed supply line can restrict flow enough to keep the solenoid energized past the 35-second limit. Check the shut-off valve, supply line routing, and inlet screen for debris.

  2. 02

    Faulty or clogged flow meter

    Part replacement

    The flow meter turbine can become stuck or fouled with mineral deposits, preventing it from signaling water delivery to the control board. Even if water is moving, a non-responsive flow meter will cause the solenoid to stay open until timeout.

  3. 03

    Failed water valve solenoid

    Part replacement

    A solenoid coil that reads outside the specified 160 to 165 ohm range indicates a failed coil. A coil with too high resistance may not open fully, and one with too low resistance may indicate a short, both of which disrupt normal fill cycles.

  4. 04

    Frozen or blocked water fill tube

    Wiring / connection

    Ice buildup in the fill tube leading to the ice mold can block water flow entirely, causing the solenoid to remain open while the control waits for the flow meter to register delivery. Inspect the fill tube for ice obstructions.

  5. 05

    Control board fault

    Part replacement

    If the solenoid resistance, flow meter, and water supply all check out within spec, the control board circuit managing the solenoid relay may be holding the output energized incorrectly. This is the least common cause and should be diagnosed only after ruling out all other components.

See the test procedure for each cause

Frequently asked questions about 30 U 30

What does 30 U 30 mean on a Sub-Zero refrigerator?
Error code 30 U 30 means the icemaker water valve solenoid was held energized for more than 35 seconds during a fill cycle without the flow meter confirming water delivery. As a safety measure, the refrigerator disables the icemaker system to prevent overflow. The code points to a problem with water supply, the flow meter, or the solenoid itself. The icemaker will remain disabled until the fault is cleared manually.
How do I fix error code 30 U 30 on my Sub-Zero refrigerator?
Start by confirming the water supply valve is fully open, the supply line is not kinked, and the inlet screen is free of debris. Next, test the water valve solenoid with a multimeter: it should read between 160 and 165 ohms. If the solenoid and supply check out, inspect the flow meter for a stuck or fouled turbine. Once the root cause is corrected, press and hold the ALARM key for 15 seconds to clear the fault and re-enable the icemaker.
Will resetting the refrigerator clear the 30 U 30 error code?
A simple power cycle will not permanently clear this code. The Sub-Zero control requires you to press and hold the ALARM key for 15 seconds after the underlying problem has been corrected. If the root cause is not fixed before resetting, the code will return as soon as the icemaker attempts another fill cycle.
Is error code 30 U 30 a safety concern?
The code itself represents the refrigerator responding correctly to a potentially unsafe condition. The control disables the icemaker to prevent the water valve from running indefinitely and causing a leak or flood inside or around the unit. As long as the icemaker is disabled, there is no active flooding risk, but the underlying issue that triggered the fault should be diagnosed and repaired promptly.
How much does it cost to repair a Sub-Zero refrigerator showing error code 30 U 30?
Repair costs vary depending on the failed component and labor rates in your area. A water valve solenoid or flow meter replacement typically ranges from around 150 to 400 dollars including parts and labor. If the fault is simply a restricted supply line or closed shut-off valve, there may be no parts cost at all. Control board replacement, the least common cause, can push costs considerably higher, often in the 400 to 800 dollar range or more.

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