Washer-dryer combo will not start or advance; display shows F05 and may indicate a door or water level issue.

Safety first: Unplug the appliance. Some internal edges can be sharp; wear cut-resistant gloves.

Step-by-step checks:

• Locate the pressure switch: Typically mounted near the top side wall under the top cover. A small rubber or plastic hose runs from the tub/air dome to the switch.
• Inspect the pressure hose: Remove the hose from the switch and from the tub/air dome. Blow gently through it; it should be clear. If blocked with soap scum, rinse and clear it fully.
• Check the air dome: Where the hose connects to the tub, inspect for buildup. Clean any residue that could trap air or block pressure changes.
• Test the switch: With a meter, check continuity across the switch terminals while gently blowing into the port. You should see contacts change state as pressure increases. Refer to the wiring diagram for correct terminals.
• Inspect wiring: Ensure the harness from the switch to the control board is intact and firmly connected.

When to replace: If the hose and air dome are clear but the switch does not change continuity with pressure, replace the water level pressure switch. If the switch tests good and F05 persists, suspect the main control board.