Sub-Zero error code · 15 U 00
Sub-Zero Code 15 U 00: Water Valve Relay Stuck Open
Sub-Zero code 15 U 00 means the water valve relay is stuck open with no power to the water valve. The fix is to verify and replace the control board.
Sub-Zero code 15 U 00 means the water valve relay is stuck open, leaving no power to the water valve. The relay is on the control board, so the repair is to verify the fault and replace the control board; inspect the water valve as well.
What 15 U 00 indicates
The water valve relay on the control board energizes the water inlet solenoid for the icemaker and dispenser. Stuck open, the relay cannot deliver power to the valve, so no water is supplied for fill or dispensing. Sub-Zero directs verifying the condition and replacing the control board because the relay is integral to it.
Likely causes
- Water valve relay stuck open on the control board
- Aged or surge-damaged relay losing contact
- Degraded solder joints at the relay on the board
- Failed water inlet valve solenoid compounding the no-water symptom
What causes 15 U 00
The valve relay switches an inductive solenoid load repeatedly, and contacts can wear, pit, or fail to close over time. Contact arcing, in-rush current, and aging board solder joints contribute. Power surges can also leave the relay open and unable to energize the valve.
Symptoms you may notice
- No water dispensed and no ice production
- Icemaker never fills despite being switched on
- Empty ice bin that does not refill
- Fault code 15 U 00 stored or shown in service mode
- Dispenser pad presses produce no flow
Parts typically replaced for 15 U 00
- 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 and replace only if the solenoid is found open or faulty during diagnosis
Owner-safe checks for 15 U 00
- Power the unit off at the breaker for two minutes, then restore power to see if the code clears
- Confirm the household water supply shutoff is fully open and the line is not kinked
- Verify the icemaker is switched on so a turned-off icemaker is not mistaken for this fault
- Note the exact code and whether it returns after the power cycle
When to call a technician
The water valve relay is built into the control board; a technician must confirm the stuck-open relay, replace the board, and verify the inlet valve energizes and fills correctly.
Frequently asked
Sub-Zero 15 U 00: people also ask
What does Sub-Zero code 15 U 00 mean?
Code 15 U 00 means the water valve relay on the control board is stuck open, so it cannot send power to the water inlet valve. With the valve never energized, no water reaches the icemaker fill or the dispenser. Because the relay is built into the board, Sub-Zero treats this as a control board fault, though the inlet valve should also be inspected.
Why do both my ice and dispenser water stop with 15 U 00?
The water valve relay feeds the single inlet valve that supplies both the icemaker and the dispenser, so when it is stuck open neither gets water. That is what distinguishes 15 U 00 from the selecting-relay fault 15 9 66, where ice keeps being made and only the dispenser dies.
Can I do anything about 15 U 00 myself?
Owner-safe checks are confirming the household water shutoff is fully open, the supply line is not kinked, and that the icemaker is actually switched on so a turned-off icemaker is not mistaken for this fault. The repair itself, replacing the board and checking the inlet valve, requires a technician.
How do I reset the 15 U 00 code?
Switch the unit off at the breaker for about two minutes, then restore power and check whether water flow returns and the code stays cleared. A genuine stuck-open relay will keep the valve dead and re-log 15 U 00, indicating the board needs replacement.
Is it urgent to fix 15 U 00?
It is a medium-urgency fault. There is no flooding risk because the valve stays off, but you lose all dispensed water and ice production, and an empty ice bin will not refill. Cooling is unaffected, so you can keep using the refrigerator while you arrange service.
Which parts are involved and what will the repair cost?
The primary fix is a new control board, since the water valve relay is integral to it; the water inlet valve is replaced only if the solenoid is found faulty during diagnosis. We charge a flat $89 diagnostic, warranty the work for 365 days, and you can call (650) 668-1554 for scheduling and an estimate.
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