The F1 error on your Bosch Dishwasher means the control board has detected a continuous water fill fault, usually triggered by the Aquastop safety system. Turn off the water supply and check the inlet hose and float switch before resetting the machine.
| Error code | F1 |
|---|---|
| Meaning | Water fill or Aquastop safety fault — the dishwasher has sensed water flowing for too long or a leak in the base tray |
| Severity | Medium — the dishwasher will not run a cycle until this is cleared, but it prevents flooding |
| Time to fix | 15–40 minutes |
| Tools needed | Torch, towel, adjustable pliers (optional) |
What the F1 error means
Bosch dishwashers use a float switch and flow meter to monitor how much water enters the tub during the fill stage. If water keeps flowing past the expected time, or if the float switch in the base of the machine detects water where it shouldn't be, the control board locks out the cycle and shows F1 as a protective measure. This is the same logic used in the Aquastop hose, which shuts off water supply if a leak is detected anywhere along the line.
It's a safety-first fault rather than a sign the dishwasher is broken beyond repair — most cases trace back to a stuck valve, a blocked drain, or a tripped float switch rather than a failed control board.
Common causes
- Inlet water valve stuck partly open, letting water trickle in continuously
- Float switch in the base tray triggered by a small leak or condensation
- Aquastop hose has detected pressure loss and shut off the supply
- Blocked or kinked drain hose causing water to back up
- Debris or a misaligned float sensor preventing it from resetting
- Faulty flow meter sending incorrect fill data to the control board
How to fix the F1 error
- Turn off the water supply and power — Isolate the dishwasher at the stopcock and unplug it or switch off at the wall for at least 2 minutes.
- Check the base tray for water — Tilt the dishwasher forward slightly and look underneath for pooled water; dry it thoroughly with a towel if found.
- Inspect the float switch — Open the lower access panel and confirm the float rises and falls freely without debris jamming it.
- Examine the inlet and Aquastop hose — Look for kinks, cracks, or a swollen safety valve; straighten or replace the hose if damaged.
- Clear the drain hose — Detach and flush it to remove any blockage that could cause water to back up into the tub.
- Restore power and run a short cycle — Plug the dishwasher back in, turn the water on, and run a rinse cycle to confirm the F1 code has cleared.
FAQ
Can I reset the F1 error myself without calling an engineer?
Yes, in most cases. Isolating the power and water supply for a few minutes, then checking the float switch and hoses, clears the fault without needing a technician.
Is it safe to keep using the dishwasher if F1 keeps coming back?
No. A recurring F1 means the machine keeps detecting a water fault, and running it repeatedly risks a leak or flood. Get the float switch and inlet valve checked before running further cycles.
Does F1 mean the control board needs replacing?
Rarely. Most F1 faults are caused by water sensing issues rather than the board itself. A board replacement is only needed if all hoses, valves, and the float switch test fine and the fault persists.
If you're also dealing with other Bosch appliance faults around the house, guides like Bosch Drill Won'T Start: Causes and How to Fix It and Bosch Drill Overheating During Use: Causes and How to Fix It cover similar step-by-step troubleshooting. For power tool issues, see Bosch Drill Chuck Won'T Tighten: Causes and How to Fix It or Bosch Drill Battery Not Connecting: Causes and How to Fix It.
