Won't drain

The warm water supply and rinse water connectors at the water supply valve look similar and can be accidentally swapped during reassembly. This causes 4C water supply errors because the wrong valve opens at the wrong time. Always label or photograph connectors before disconnecting.

In cold climates, frozen water supply lines and internal components are a root cause for multiple seemingly unrelated error codes: 4C (no water supply), 5C (drain pump frozen), HC1 (heater fires with no water), OC (frozen valve stuck open), and temperature sensor errors. Always check for freezing conditions in winter before replacing parts.

The door diaphragm (boot seal) is easily damaged during removal. Always use long nose pliers, start at the spring ring connection point, and work slowly in one direction only. For easier removal, use a flat screwdriver to release the spring from the lower part first. Rushing this step or working from multiple directions tears the rubber.

If an incorrect water level sensor part number is installed (even if it physically fits), the machine will behave abnormally without necessarily throwing an error code. Always verify the material/part code matches the service parts list for the specific model. This is a common issue when substituting parts from similar Samsung models.