Appliance Spares
Quick answer: The Bosch F18 error code is a drainage fault—it means the machine could not empty the drum within the allotted drain time. F18 and E18 are the same underlying fault; Bosch simply uses different prefix letters across model generations. A blocked pump filter is the cause in the majority of cases and is free to fix. If the filter and hose are clear, the drain pump motor needs replacing—around $49.95 for a compatible part.
Not sure which one fits? Match your model number or check the sticker inside the door.
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Parts for your model: Bosch drain pump WAW28620AU / WAW28790AU — $49.95 · WAP28380AU / WAP28482AU — $49.95 · find your model
Is F18 the same as E18 on a Bosch washing machine?
Yes—F18 and E18 are the same drainage fault code. Bosch uses “E” as the fault prefix on some display generations (particularly older Classixx, Logixx, and early Avantixx models) and “F” on others (many Series 4, 6, and 8 models). The underlying fault condition, the diagnosis process, and the repair steps are identical regardless of which letter your display shows.
Both codes mean: the machine started a drain cycle and the water level sensor confirmed that water was still present in the drum at the end of the allotted drain period. The control board then halted the cycle to avoid overflow or motor overload.
What causes the F18 / E18 drainage fault?
The cause breakdown across Australian Bosch front loaders is consistent regardless of whether your display shows F18 or E18.
| Cause | Likelihood | Typical fix |
|---|---|---|
| Blocked pump filter | Very common | Clean filter — free |
| Kinked or blocked drain hose | Common | Straighten or clear — free |
| Drain hose outlet too high | Common (especially after a move) | Re-route hose — free |
| Failed drain pump motor | Moderate | Replace pump — ~$50 part |
| Pressure sensor fault | Uncommon | Replace sensor — ~$40 part |
How to fix Bosch F18 step by step
- Power off and unplug. Turn the programme dial to off and remove the power plug. Wait two minutes before proceeding.
- Drain residual water via the filter port. Open the small access flap at the bottom front of the machine (usually lower right). Place a shallow tray beneath it. Slowly turn the filter cap anti-clockwise to release trapped water gradually.
- Remove and clean the filter. Once the water has drained, pull the filter cap out fully. Remove any lint, debris, or foreign objects. Rinse under running water and refit, turning clockwise until hand-tight.
- Check the drain hose. Pull the machine away from the wall and inspect the grey corrugated hose from the back of the machine to the standpipe or sink trap. Straighten any kinks. Confirm the hose outlet sits no higher than 100 cm above floor level.
- Plug in and test. Run a Spin or Rinse+Spin cycle. If the machine drains and F18 does not return, the filter or hose was the cause.
- Replace the drain pump if needed. If F18 returns after the above steps, the pump motor has likely failed. The pump is the same component whether your machine shows E18 or F18. Check your model sticker (inside the door frame) and select the correct pump below, or use the Part Finder:
Repair cost guide
| Option | Cost | Time |
|---|---|---|
| Clean pump filter (DIY) | Free | 10 minutes |
| Pump replacement (DIY) | ~$50 part | 30–45 minutes |
| Tradie call-out + pump | $180–$300 | 1–2 hours |
Frequently asked questions
Does F18 mean my Bosch pump is definitely broken?
Not necessarily. In most cases the pump is working but is impeded by a blocked filter or a drain hose issue. Clean the filter and check the hose first—these are free fixes. Only if the fault persists after those checks should you consider replacing the pump.
Why does my machine show F18 instead of E18?
Bosch changed the display convention across production runs. Machines manufactured from roughly 2015 onwards often show “F”-prefixed codes; older machines show “E”-prefixed codes. Both conventions refer to the same internal fault conditions.
Can F18 appear even if the pump sounds like it’s running?
Yes. A partially blocked filter reduces flow rate enough to trigger a drain timeout even when the pump motor itself is still turning. If you can hear the pump hum but the drum is not emptying efficiently, a blocked filter is the most likely cause.
Will the machine damage itself if I keep running it with F18 active?
The control board stops the cycle when F18 is triggered, which protects the motor. However, leaving standing water in the drum for extended periods can encourage mould and odours. Address the fault promptly.
My Bosch is under warranty — does F18 void it if I clean the filter myself?
Cleaning the pump filter is a standard user-maintenance task described in the Bosch owner’s manual. It does not void the warranty. Replacing parts yourself on an in-warranty machine may affect warranty coverage—check your warranty terms if the machine is recent.
Related
Disclaimer: this article is general information only and is provided without warranty of any kind. Appliance designs vary between models and production runs — always follow the manufacturer’s instructions, switch off and unplug the appliance before starting any work, and confirm parts against the model number on your appliance’s model sticker. Any repair is undertaken at your own risk and Oz Appliance Spares accepts no liability for injury, loss or damage arising from work performed after reading this guide, to the maximum extent permitted by law. If in doubt, use a qualified technician.
