Sub-Zero error code · 15 U 01
Sub-Zero Code 15 U 01: Water Valve Relay Stuck Closed
Sub-Zero code 15 U 01 means the water valve relay is stuck closed with power to the water valve at all times, risking flooding. Replace the control board.
Sub-Zero code 15 U 01 means the water valve relay is stuck closed, leaving power applied to the water valve at all times, which can flood the icemaker or dispenser. The relay is on the control board, so the repair is to verify and replace the control board; shut off the water supply until serviced.
15 U 01, explained
The water valve relay on the control board energizes the inlet solenoid. Stuck closed, the relay keeps the valve powered continuously, so water flows whenever the inlet solenoid is healthy enough to open, risking overfill and leaks. The flashing SERVICE light with chime signals an active fault, and Sub-Zero directs verifying and replacing the control board.
Severity:Service needed · Service light:FLASH W/CHIME
How 15 U 01 shows up
- Flashing SERVICE light with an audible chime
- Continuous or excessive water flow, overfilled icemaker, or leaking
- Water in or under the unit, or ice bin flooding
- Fault code 15 U 01 stored or shown in service mode
- Inlet valve buzzing or running when it should be idle
What usually causes it
- Water valve relay contacts welded closed on the control board
- Surge-damaged or aged relay stuck in the energized state
- Degraded solder joints holding the relay circuit closed
- Internal board fault keeping power applied to the valve
Which part 15 U 01 points to
- Control board — Primary fix; the water valve relay is integral to the board, so Sub-Zero specifies verify and replace board
- Water inlet valve — Inspect for damage from continuous power and replace if the solenoid is compromised
Why 15 U 01 appears
Relay contacts weld closed after years of switching the solenoid load, leaving the circuit permanently energized. Contact arcing, heat, in-rush current, and power surges drive the failure. Aging board solder joints can also keep the relay path closed.
What you can safely check
- Shut off the household water supply to the unit to prevent flooding until service
- Power the unit off at the breaker for two minutes, then restore power to see if the code clears
- Wipe up any standing water and watch for renewed flow
- Note the exact code and the flashing-light-with-chime alert
When 15 U 01 needs a technician
Constant power to the water valve can cause flooding; the relay is built into the control board, so a technician must verify the stuck-closed relay and replace the board promptly.
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Frequently asked
Sub-Zero 15 U 01 — questions
What does Sub-Zero code 15 U 01 mean?
Code 15 U 01 means the water valve relay on the control board is stuck closed, leaving power applied to the water inlet valve at all times. Whenever the inlet solenoid opens, water keeps flowing, which can overfill the icemaker and dispenser and lead to leaks. The flashing SERVICE light with a chime signals this active fault.
What should I do right now if I see 15 U 01?
Shut off the household water supply to the refrigerator immediately to stop any continuous flow and prevent flooding. Then wipe up standing water, note the flashing-light-with-chime alert, and call for service. This is the one error in this family where you should cut the water before a technician arrives.
How is 15 U 01 different from 15 U 00?
They are opposite states of the same water valve relay. 15 U 01 is stuck closed, so the valve is powered constantly and water can overfill or leak, which is why it carries a chime and high severity. 15 U 00 is stuck open, so the valve never gets power and you simply lose all water and ice with no flood risk.
Can I clear or reset 15 U 01 myself?
You can shut the water off and try a breaker power cycle of about two minutes, but a welded relay will keep the valve energized and re-trigger the chime. Resetting will not stop the flooding, so the only real fix is having the control board replaced; leave that to a technician.
Is it safe to keep using the unit with 15 U 01 active?
No, this is a high-urgency fault. Continuous power to the inlet valve can flood the ice bin and the surrounding floor and may damage the valve itself. Keep the water supply off and have the board replaced promptly rather than continuing to run the unit with the water connected.
What does the repair involve and what will it cost?
The control board is replaced because the water valve relay is built into it, and the inlet valve is inspected for damage from being continuously powered and replaced if compromised. Our diagnostic is a flat $89, the repair is covered by a 365-day warranty, and you can reach us at (650) 668-1554 for prompt scheduling.
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