An ice maker shut-off valve is the household stop on the 1/4-inch supply line feeding the refrigerator, and closing it cuts water to the ice maker without closing the house main. Switch the ice maker off first, then close the valve: a quarter-turn lever is shut at 90 degrees across the pipe, and a round handle turns clockwise until it stops.

A built-in Sub-Zero also has an internal water valve, and a half-closed stop often shows up as a fault code, not a puddle.

What does each valve on the ice maker water line do?

The household shut-off valve is house plumbing: a quarter-turn ball valve, a multi-turn compression stop, or an older saddle valve clamped onto copper pipe. On a built-in, panel-ready Sub-Zero, the stop usually sits in an adjacent cabinet or under the sink.

The Sub-Zero water valve sits in the machine compartment; the control energizes its solenoid for each fill, then cuts power so the valve snaps shut. Owners never touch that valve.

How do you close the water supply to a built-in ice maker?

Step 1: Switch the Sub-Zero ice maker off so the control stops calling for water.

Step 2: Find the shut-off valve by tracing the tubing from the refrigerator.

Step 3: Close the valve gently; a corroded stem forced too hard can snap and leave water running.

Step 4: Relieve pressure by holding a glass under the Sub-Zero dispenser, if fitted.

Step 5: Reopen the stop fully, watch the fittings for drips for an hour, then switch the Sub-Zero ice maker back on and discard the first batches of ice.

Does shutting off the water affect the ice maker?

Yes, if the Sub-Zero ice maker is left on. The control keeps opening the water valve, gets no flow, and after repeated long fills disables the ice maker to prevent flooding. A partly open stop triggers the same codes.

Sub-Zero 600 and 700 Series: EC 30 with Service flashing means the ice maker cycled off after excessive water valve activation. Turn the ice maker off, open the supply, and report the code and temperatures if it returns.

Sub-Zero 600 Series code 30: the solenoid was energized over 15 seconds, 5 times. Check for a jammed cube before calling. If SERVICE and ICE both flash, turn the unit off for 10 seconds and back on; call if it recurs often.

Sub-Zero Classic (BI): a single ice cube icon flashing without an alarm means the water valve stayed open too long and was disabled. Check the supply, then hold Alarm until CFC (Clear Fault Codes) appears.

Sub-Zero UC-15I: a flashing blue ice light means automatic shut-off after two maximum-length cycles or 120 cycles without filling the bin. Make sure the water is on, allow 1 hour, and try removing the water filter.

Why do shut-off valves leak, seize or starve the ice maker?

Drip at the stem: dried packing in a multi-turn shut-off valve. Snug the packing nut an eighth of a turn; if it still drips, replace the valve.

Frozen handle: mineral scale locks an old compression stop; close the house main and let a plumber replace it.

Saddle valve: its small pierced hole clogs with scale and the clamp can weep, giving a Sub-Zero ice maker slow, undersized ice.

Kinked tubing: sliding a built-in Sub-Zero into a tight opening can fold the line behind it, cutting flow even with the stop fully open.

Is a valve problem DIY or technician work?

Owners can turn the stop, snug a packing nut, clear a jammed cube and run the resets above. A plumber replaces a seized, leaking or saddle-type shut-off valve. A technician handles water inside the Sub-Zero cabinet, a humming internal valve that never fills, returning codes and pulling a built-in out. Sub-Zero Fremont Repair Co. publishes a $275-$850 band for ice maker and water line repairs, and the $89 service call is waived when you book the repair.