Miele Dishwasher Error Code F78

Miele Dishwasher Error Code F78

Error code F78 indicates a water inlet valve malfunction or water supply issue on Miele dishwashers sold in the USA. This error prevents the dishwasher from filling properly with water during the wash cycle.

Symptoms

• Dishwasher fails to fill with water during the wash cycle
• Cycle stops midway through operation
• Error code F78 displays on the control panel
• No water sound or flow heard during startup
• Dishes remain dry after cycle completion
• Water may not reach the spray arms

Possible Causes

• Clogged or kinked inlet hose connections
• Water supply valve to the dishwasher is closed or partially closed
• Faulty water inlet valve solenoid (120V electrical component)
• Debris or mineral deposits blocking the inlet valve filter screen
• Defective water level sensor
• Main control board malfunction
• Low household water pressure below minimum 20 PSI required for USA models
• Frozen water supply line (in cold climates)
• Broken or damaged inlet hose

Safe Checks You Can Do

• Verify the water supply valve located behind or under the dishwasher is fully open by turning the valve handle counterclockwise
• Check that the inlet hose is not kinked, pinched, or frozen
• Inspect the inlet hose for visible cracks, leaks, or damage
• Ensure the dishwasher door is fully closed and properly latched
• Verify that your home circuit breaker powering the dishwasher has not tripped; reset if necessary
• Remove and rinse the dishwasher filter basket and check for debris blocking water flow
• Check spray arms for blockages and ensure they rotate freely
• Test water pressure at a nearby faucet to confirm adequate household water supply
• Perform a complete appliance reset by switching off the circuit breaker for 60 seconds, then switching it back on
• Consult your user manual for the inlet valve filter screen location and gently flush it if accessible without disassembly

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