Sub-Zero error code · 50 U 87
Sub-Zero Code 50 U 87: Water Flow Meter Detected No Flow
Sub-Zero code 50 U 87 means the flow meter detected no water flow. Check water pressure and supply, and confirm the meter is not blocked or dirty.
Sub-Zero code 50 U 87 means the water flow meter registered no flow during a dispense attempt. The fix is to restore water supply and pressure to the unit and confirm the flow meter itself is not blocked or dirty.
What 50 U 87 indicates
This code indicates the dispenser was commanded to deliver water but the flow meter sensed none passing through. The control board sees zero measured flow, which signals either no water reaching the meter or a meter that is fouled and not registering. It typically means the water path is interrupted or the meter is obstructed.
Symptoms you may notice
- No water comes out when the dispenser is pressed
- Service mode shows code 50 U 87
- Ice maker may also stop if it shares the supply
- No sound of water moving during a dispense attempt
- Often follows a frozen line, closed valve, or very old filter
What causes 50 U 87
No flow is usually caused by a closed or failed supply valve, a fully clogged water filter, or a frozen, kinked, or disconnected supply line. The flow meter can also become blocked with debris or scale so its impeller no longer turns, or it can fail to read flow that is actually present. A stuck or dead inlet water valve will also produce no flow.
Likely causes
- Closed supply shutoff valve or no water to the unit
- Fully clogged water filter cartridge
- Frozen, kinked, or disconnected supply line
- Flow meter blocked or dirty so the impeller will not turn
- Stuck or failed inlet water valve
Parts typically replaced for 50 U 87
- Water flow meter assembly — Replace when supply and pressure are confirmed but the meter is blocked, dirty, or not reading flow
- Inlet water valve — Replace if the valve will not open and no water reaches the meter
Owner-safe checks for 50 U 87
- Confirm the supply shutoff valve is fully open and water is on
- Replace a very old or clogged water filter
- Check the supply line for kinks or signs of freezing
- Power-cycle the unit and retest a dispense
When to call a technician
If supply, pressure, and the filter are good but flow is still zero, a technician is needed to test the inlet valve and determine whether the flow meter is blocked or has failed.
Frequently asked
Sub-Zero 50 U 87: people also ask
What does Sub-Zero code 50 U 87 mean?
Code 50 U 87 means the dispenser was commanded to deliver water but the flow meter registered no flow at all. The board sees zero measured flow, which signals either no water reaching the meter, or a meter so fouled it cannot read flow that is present. It usually means the water path is interrupted, by a closed valve, clogged filter, or frozen line, or the meter is blocked.
Can I resolve code 50 U 87 on my own?
You can do the first checks: confirm the supply shutoff valve is fully open and water is on, replace a very old or clogged water filter, inspect the supply line for kinks or signs of freezing, then power-cycle and retest. If those restore water, you are done. If flow is still zero, a technician is needed to test the inlet valve and check whether the flow meter is blocked or failed.
How do I clear code 50 U 87?
Once water actually flows through the meter again, after restoring supply, thawing or unkinking the line, or replacing a clogged filter, the meter registers flow and 50 U 87 clears. A power-cycle and a test dispense confirm it. If the code persists with good supply and a fresh filter, the inlet valve or the flow meter itself is the holdup.
How urgent is code 50 U 87?
Cooling and food safety are unaffected, so it is not a food emergency, but no water is dispensing and the ice maker may also stop if it shares the supply. One common trigger is a frozen supply line, which is worth checking promptly. It is medium severity, address it soon to restore water and ice, but it does not threaten the contents of the unit.
Which part does 50 U 87 point to and what does the repair cost?
If supply, pressure, and the filter are confirmed good, the suspects are the inlet water valve (stuck or failed so no water reaches the meter) or the water flow meter assembly (blocked, dirty, or not reading). Owner filter and supply checks are free; if a technician is needed, the diagnostic is a flat $89 with a 365-day warranty, bookable at (650) 668-1554.
How can I tell 50 U 87 apart from the low-flow code 50 U 86?
50 U 87 is zero flow, the meter senses nothing during a dispense, so look for a fully closed valve, a completely clogged filter, a frozen or disconnected line, or a blocked meter. 50 U 86 is reduced flow, the meter sees water but less than expected, usually a partly clogged filter or low pressure. No water at all is 50 U 87; a weak trickle is 50 U 86.
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