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Error code reference

Thermador Range Error Code F

Dishwasher

Thermador codesThermador range codes

Dishwasher: Water level or filling error (underfill, overfill or water in the base).

First step from the service manual

Correct cause; code will reset itself 15 minutes after dishwasher turned on, or by running diagnostic program.

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

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What F means on a Thermador range

The F error code on a Thermador range-integrated dishwasher indicates a water level fault. This code is triggered when the dishwasher's water management system detects an abnormal water condition during operation. The three specific fault conditions that activate this code are underfilling (the tub did not receive enough water within the expected timeframe), overfilling (water level exceeded the safe maximum), or water detected in the base pan beneath the tub assembly. The control board monitors water level through a pressure switch or float sensor, and when readings fall outside the acceptable parameters, the F code is generated and the cycle is interrupted.

Water in the base is often the most serious of the three conditions, as it typically indicates an active leak from an internal component such as a door seal, hose connection, spray arm fitting, or pump housing. The base pan on many dishwasher designs includes a float switch that trips when pooled water is detected, immediately flagging the error to prevent motor damage or further leakage. Underfill faults generally point to a restricted water supply, a faulty inlet valve, or low household water pressure. Overfill conditions often stem from a stuck-open inlet valve or a malfunctioning water level sensor that fails to signal the control board to stop filling.

According to the diagnostic procedure, the F code will clear itself automatically 15 minutes after the dishwasher is powered on, provided the underlying cause has been corrected. It can also be cleared by running the built-in diagnostic program. Simply resetting the code without addressing the root cause will result in the error returning during the next wash cycle.

Source: manufacturer service documentation.

Common causes of F

  1. 01

    Water in the base pan

    Part replacement

    A leak from a door gasket, hose connection, pump seal, or spray arm fitting can allow water to pool in the bottom pan and trip the float switch. Check beneath the tub for standing water and inspect all visible seals and hose connections.

  2. 02

    Faulty or stuck water inlet valve

    Part replacement

    An inlet valve that fails to open properly causes underfill, while one that sticks open causes overfill. Listen for the valve during the fill phase and check the water supply connection for adequate flow and pressure.

  3. 03

    Kinked or blocked water supply line

    Wiring / connection

    A restricted supply line reduces water flow into the tub, triggering an underfill fault. Inspect the inlet hose behind the unit for kinks, and verify the supply shutoff valve is fully open.

  4. 04

    Malfunctioning water level pressure switch or float sensor

    Part replacement

    If the pressure switch or float sensor provides inaccurate readings to the control board, the unit may incorrectly report an overfill or underfill even when water levels are normal. The sensor or switch may need to be tested and replaced.

  5. 05

    Low household water pressure

    Wiring / connection

    Insufficient incoming water pressure can prevent the tub from filling to the required level within the allotted time, resulting in an underfill error. Check that your home's water pressure meets the minimum requirement for the appliance.

See the test procedure for each cause

Frequently asked questions about F

What does F mean on a Thermador range?
The F code on a Thermador range refers specifically to a dishwasher water level or filling error. It activates when the dishwasher detects that the tub received too little water, too much water, or that water has accumulated in the base pan beneath the tub. The code halts the cycle to prevent damage and requires the underlying cause to be identified and corrected before normal operation can resume.
How do I fix the F error code on my Thermador dishwasher?
Start by identifying which of the three fault conditions applies: underfill, overfill, or water in the base. Check the water supply line for kinks, verify the shutoff valve is fully open, inspect the door gasket and hose connections for leaks, and look for standing water in the base pan. Once the cause is corrected, the code will reset on its own 15 minutes after the dishwasher is turned on, or you can run the diagnostic program to clear it sooner.
Will resetting the Thermador dishwasher clear the F code?
The F code will clear itself 15 minutes after the dishwasher is powered on, or by running the built-in diagnostic program, but only after the root cause has been resolved. If the underlying water level problem is not addressed, the error will return as soon as the next cycle begins. Resetting alone without fixing the cause is not a permanent solution.
Is the F error code on a Thermador dishwasher a safety concern?
The water-in-base condition associated with this code can indicate an active internal leak, which warrants prompt attention. Allowing water to accumulate in the base pan can lead to motor or component damage over time. If you suspect a leak, avoid running the dishwasher until the source has been identified and repaired.
How much does it cost to repair the F error code on a Thermador dishwasher?
Repair costs depend on the cause. Clearing a kinked supply line or adjusting the shutoff valve costs nothing. Replacing a water inlet valve typically ranges from $75 to $200 including parts and labor. Repairing a leak involving a door gasket, pump seal, or hose connection can range from $100 to $350 or more, depending on the component and the labor involved. A faulty water level sensor or pressure switch replacement generally falls in the $80 to $200 range.

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