The nF error means no water fill detected within time limit — machine couldn't fill to required level.
The Samsung front-load washer displays the nF error and halts the current cycle until the underlying problem is fixed.
Check these in order. The first cause accounts for the majority of nF errors.
The supply valve at the wall is partially closed or the hose behind the machine is kinked. This is the most common cause — check before anything else.
Fine mesh screens inside the water inlet valve trap sediment over time. Even partial blockage reduces flow below the threshold needed to fill within the time limit.
If water pressure at the machine drops below ~20 PSI, the washer can't fill fast enough. Test a nearby faucet — if flow is weak, the issue is upstream.
If hoses and screens are clear and pressure is fine, the inlet valve solenoid may have failed open-circuit. Test with a multimeter and replace if no continuity when energized.
Follow these in order. Stop as soon as the error clears.
Cut power before any inspection. Wait 60 seconds.
Pull the machine slightly forward. Inspect both hot and cold hoses for kinks or tight bends against the wall.
At the wall, turn both shutoff valves counterclockwise as far as they go.
Disconnect supply hoses at the machine. Use needle-nose pliers to remove the small mesh screens from the inlet ports. Rinse under running water to clear sediment. Reinstall and reconnect hoses.
Run the kitchen or bathroom faucet full-blast. If flow seems weak house-wide, contact your water utility — low pressure can't be fixed at the machine.
Restore power. Run a Rinse+Spin cycle. If nF returns with all the above clear, replace the inlet valve.
For warranty service, contact Samsung support ↗ or a certified appliance technician.