Sub-Zero Refrigerator Error Code 50 U 87

Error code 50 U 87 means the water flow meter did not detect any water movement during a fill cycle. The refrigerator monitors water flow with an inline sensor, and this code appears when that sensor registers zero flow after the control board commands water to run. The fault points to a supply pressure issue, a blockage, or a problem with the flow meter or inlet valve itself.

The refrigerator itself will continue to cool normally while this code is active, so food safety is not immediately compromised. However, the ice maker and water dispenser will not function correctly until the water flow issue is resolved. Leaving the fault unaddressed for an extended period can allow ice maker components to run dry and wear prematurely.

Repair costs vary depending on the cause. If the fix is simply opening a shutoff valve or clearing a kinked line, there is no parts cost involved. Replacing a clogged inlet valve screen is inexpensive, typically in the range of a few dollars to around twenty dollars for the part. A new flow meter or water inlet valve assembly on a Sub-Zero unit can cost anywhere from roughly sixty to over two hundred dollars for parts alone, with additional labor costs if a technician performs the repair.

Start by confirming the water supply shutoff valve is fully open and that household water pressure is adequate at the refrigerator connection. Next, inspect the water supply line for kinks, check the inlet valve screen for sediment buildup, and examine the flow meter for debris or mineral scale on the impeller. If cleaning does not resolve the fault, the flow meter or water inlet valve may need to be replaced.

A reset may temporarily clear the displayed code, but if the underlying water flow problem has not been corrected the fault will return as soon as the refrigerator attempts another fill cycle. The code should only be considered resolved after the root cause, such as a blocked flow meter, low pressure, or a faulty inlet valve, has been diagnosed and corrected.