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F18

Error code

high severity Bosch

F18 Error: If your Bosch dishwasher display is showing an F18 error cod

If your Bosch dishwasher display is showing an F18 error code, your appliance has detected a water heating fault. This means the water inside your dishwasher isn't reaching the temperature it needs to clean your dishes properly, so the machine has stopped mid-cycle to prevent damage. Whilst this sounds concerning, the good news is that many F18 faults can be resolved without calling out an engineer, potentially saving you a considerable amount of money. The most common culprits behind this error are a faulty heating element, a malfunctioning thermostat, or issues with the temperature sensor that monitors water heat. Occasionally, mineral deposits from hard water can also interfere with the heating system's performance. Before you worry about expensive repairs, it's worth checking a few straightforward things yourself, such as inspecting the heating element for visible damage or ensuring your water inlet temperature is adequate during winter months. This guide will walk you through the diagnostic steps and explain which components are most likely responsible for your F18 error.

Diagnostic Steps

  1. 1

    Step 1

    Check the heating element is not scaled up — descale if necessary

  2. 2

    Step 2

    Test the NTC thermistor for correct resistance

  3. 3

    Step 3

    Inspect wiring connections to the heater

  4. 4

    Step 4

    If element is faulty, replacement is required

⚠️ Always disconnect your appliance from mains power before starting any repair. If in doubt, consult a qualified engineer.

Frequently Asked Questions

What does the F18 error mean on a Bosch dishwasher?↓
If your Bosch dishwasher display is showing an F18 error code, your appliance has detected a water heating fault. This means the water inside your dishwasher isn't reaching the temperature it needs to clean your dishes properly, so the machine has stopped mid-cycle to prevent damage. Whilst this sounds concerning, the good news is that many F18 faults can be resolved without calling out an engineer, potentially saving you a considerable amount of money. The most common culprits behind this error are a faulty heating element, a malfunctioning thermostat, or issues with the temperature sensor that monitors water heat. Occasionally, mineral deposits from hard water can also interfere with the heating system's performance. Before you worry about expensive repairs, it's worth checking a few straightforward things yourself, such as inspecting the heating element for visible damage or ensuring your water inlet temperature is adequate during winter months. This guide will walk you through the diagnostic steps and explain which components are most likely responsible for your F18 error.
Can I fix the F18 error myself?↓
Many F18 faults can be resolved by a competent DIYer. Always disconnect from mains power first. If unsure, consult a qualified engineer.

Quick Summary

Code
F18
Brand
Bosch
Parts to check
0