Samsung Washer nF1 Error Code — What It Means
The nF1 code on a Samsung washer indicates a hot and cold water supply mix-up fault. The washer has detected that the cold-water inlet is receiving hot water, almost always because the supply hoses are reversed or the home plumbing is misconnected. This is a specific inlet-temperature error, not a general fill failure. The machine expects cold water at the cold inlet and hot water at the hot inlet, and when that relationship is wrong, it throws nF1 and stops the cycle to protect the wash process.
Common Causes
- Hot and cold hoses swapped at the washer The blue cold hose is connected to the hot inlet or the red hot hose is connected to the cold inlet at the back of the machine.
- Hoses reversed at the wall shutoff valves The connections are correct at the washer but the hoses are crossed at the supply valve end, sending hot to cold and cold to hot.
- House plumbing crossover or mislabeled lines The wall outlet labeled cold is actually delivering hot water due to upstream plumbing errors or backfeed from the hot-water system.
- Restricted or clogged inlet screens Sediment or debris in the mesh filters at the water inlets can disrupt flow and temperature sensing, though this is less common for nF1.
- Failed water inlet valve or temperature circuit If plumbing is verified correct, a faulty inlet valve, wiring harness, or control board may be misreading or misrouting the water supply.
Step-by-Step Fix
- Unplug the washer or turn off the circuit breaker to safely work on the water connections.
- Pull the washer forward far enough to access the rear panel and the two water inlet hoses.
- Verify hose routing by confirming the blue or cold-marked hose connects to the cold inlet on the washer and the red or hot-marked hose connects to the hot inlet, then trace each hose back to the wall shutoff and confirm cold-to-cold and hot-to-hot at both ends.
- Check that both shutoff valves are fully open and inspect the hoses for kinks, pinches, or crushing that could restrict flow.
- Remove and inspect the inlet screens at each water valve port on the washer, rinse any sediment or debris, and reinstall them.
- Test the wall outlets by briefly opening each shutoff into a bucket to confirm the cold line delivers cold water and the hot line delivers hot water, ruling out a plumbing crossover.
- Restore power and run a test cycle after reconnecting everything correctly, and if nF1 persists with verified correct plumbing, proceed to component diagnosis of the inlet valve, wiring, and control board.
Parts Often Needed
| Part | Notes |
|---|---|
| Water inlet valve assembly | Amazon | Main component when supply plumbing is correct but fill errors or nF1 persists. |
| Inlet screen mesh filters | Amazon | Serviceable filters at the valve ports, clean or replace if damaged or heavily restricted. |
| Inlet valve wiring harness | Amazon | Check connectors and wiring if the valve is commanded correctly but the code remains. |
When to Call a Pro
Call a technician if the nF1 code remains after you have verified that both hoses are correctly routed cold-to-cold and hot-to-hot at the washer and at the wall, and you have confirmed that the wall cold supply is truly cold and the hot is hot. Persistent nF1 with correct plumbing points to a failed inlet valve, temperature-sensing circuit, or control board issue that requires component-level diagnosis and replacement. Also call a plumber if you discover that your home’s cold supply line is delivering hot water, as that indicates a plumbing crossover upstream of the washer.