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Error code reference

Miele Dishwasher Error Code F70

Float switch fault

Miele codesMiele dishwasher codes

Float switch fault — the overflow float switch B8/3 has been activated indicating water in the drip pan; drain pump runs even after machine is switched off.

First step from the service manual

Remove water from the drip pan; check all hoses, connections and threaded unions for leaks.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What F70 means on a Miele dishwasher

The F70 error code on a Miele dishwasher indicates that the overflow float switch, designated B8/3, has been triggered. This float switch is located in the drip pan at the base of the machine. When water accumulates in the drip pan beyond a threshold level, the float rises and activates the switch, signaling the control board that a leak condition exists. In response, the drain pump is commanded to run continuously, even after the dishwasher is powered off, in an attempt to remove water and prevent further overflow or floor damage.

The drip pan is designed to catch water from any internal leak source before it reaches the floor. Common leak origins include deteriorated door seals, cracked or loose hose connections, failed threaded unions on the water inlet or circulation system, and a compromised pump housing or sump assembly. The fact that the drain pump keeps running after shutdown is a deliberate safety behavior built into the control logic, not a malfunction in itself.

Diagnosis begins by removing the dishwasher from its cabinet space, soaking up or draining all standing water from the drip pan, and then carefully inspecting every hose, clamp, threaded union, and internal connection for signs of weeping or active leakage. The float switch itself can also fail mechanically, sticking in the raised position even after water has been cleared, which would require testing or replacing the switch to confirm normal operation.

Source: manufacturer service documentation.

Common causes of F70

  1. 01

    Leaking hose connection or threaded union

    Part replacement

    Hoses connecting the water inlet, circulation pump, or drain can loosen over time, and threaded unions can develop weeps due to wear or improper seating. Inspect each connection point for moisture trails, mineral deposits, or active dripping.

  2. 02

    Worn or damaged door gasket

    Part replacement

    A deteriorated door seal allows water to escape during the wash cycle and run down into the drip pan. Check the full perimeter of the door seal for cracks, tears, or sections that have pulled away from the channel.

  3. 03

    Failed pump housing or sump seal

    Part replacement

    The circulation pump or drain pump housing can develop cracks or seal failures that allow water to drip steadily into the base tray. Look for water staining or residue on the underside of the pump assemblies.

  4. 04

    Float switch B8/3 stuck in activated position

    Part replacement

    After the drip pan water is removed, the float switch may remain in the raised position due to debris or a mechanical fault, keeping the drain pump running and the F70 code active. Test the switch for free movement and correct electrical response.

  5. 05

    Overfilling due to water inlet valve fault

    Part replacement

    A faulty inlet valve that does not fully close can allow excess water to build up inside the tub, eventually overflowing into the drip pan. This is more likely if the machine fills beyond normal operating level or fills when not in use.

See the test procedure for each cause

Frequently asked questions about F70

What does F70 mean on a Miele dishwasher?
F70 means the overflow float switch B8/3, located in the drip pan at the base of the dishwasher, has detected standing water from an internal leak. The control board responds by running the drain pump continuously, even when the machine is switched off, as a protective measure. The error will persist until the leak source is identified and repaired and the drip pan is cleared of water.
Can I fix the F70 error myself, or do I need a technician?
Some homeowners can resolve F70 by pulling the dishwasher out, mopping up the water in the drip pan, and identifying an obvious loose hose or connection that can be reseated or tightened. However, if the leak source involves the pump seals, internal hose assemblies, or a failed float switch, a qualified technician with the right tools and parts will be needed to complete the repair safely.
Is it safe to keep using my Miele dishwasher when F70 is showing?
No, you should not continue running the dishwasher while F70 is active. There is an active internal leak, and continued operation could worsen the leak, cause water damage to cabinetry or flooring, or create an electrical hazard. The dishwasher should remain off until the leak is found and corrected.
Will resetting the dishwasher clear the F70 error code?
A simple reset will not permanently clear F70 because the drain pump is designed to keep running as long as water is present in the drip pan and the float switch remains activated. Even if the display resets momentarily, the code will return until the drip pan is emptied and the underlying leak is repaired. Addressing only the symptom without fixing the leak source will not resolve the fault.
How much does it cost to repair a Miele dishwasher F70 error?
Repair costs vary depending on the leak source. A simple hose reclamp or connection reseat might cost relatively little if done without parts, while replacing a door gasket typically runs in the range of $50 to $150 in parts and labor. More involved repairs such as pump seal replacement or inlet valve replacement can range from $150 to $400 or more, depending on parts and the technician's labor rate in your area.

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