The short answer
F28 on this washing machine means there is a problem with the flow sensor — that is what the manufacturer published for it, and no more. The machine may still fill using a fallback timing, so it can often be used while the fault waits for attention. One of the checks below is an owner check, and the rest of the work is behind a panel.
Error codes
Reference| Code | Meaning |
|---|---|
| F28 | These error codes indicate there is an issue with the flow sensor. |
What the machine does alongside the code
- The code appears while the machine still fills and washes — Measurement faults often leave the function working, which is what makes them easy to live with briefly.
- You can hear the valve open with little water arriving — That separates a commanded valve from a supplied one, which is the whole question here.
What triggers F28, most likely first
- Grit or scale in the sensor, often after plumbing work — It goes first because it is the commonest and it points outward: the sensor sits behind the inlet where debris from the supply collects, and anything that disturbs the pipework sends grit straight to it.
- Low pressure at the appliance — The appliance needs the pressure the manufacturer specifies; a shared feed or a mains problem drops it below that and the fill times out.
- A safety device that has shut the water off — Last: where the appliance has a supply-side protection device, it stops the water deliberately, and the code is then the consequence rather than the fault.
Check in this order, and why
- Ask whether any plumbing work has been done recently — Grit stirred into the supply lands at the first restriction it meets, which is often this sensor.
- Look along the inlet hose behind the appliance — A tight bend or a crush at the back does not show from the front.
- Test the pressure at a nearby tap — This tells you whether the restriction is in the house or in the appliance feed.
- Body: Compare the appliance against the house before touching either: a nearby tap answers in seconds whether this is a supply problem at all.
The reset, then the owner-safe checks
- Compare with a nearby tap during the fill — Run the tap while the appliance tries to fill; poor flow at both puts the fault in the house supply.
About 10 min
- Open the tap fully, straighten the inlet hose, then power-cycle and run one short programme — You are removing the supply-side explanations before anyone opens the machine.
About 45 min
- Cut power for a minute and restart the cycle — Clears the stored code so you can see whether the fill is genuinely still failing.
About 5 min
- STOP HERE — the filter screen and the valve are service items — Both mean disconnecting water and opening the appliance, so this is where an owner check ends.
Before anything is opened
Safety
Unplug the machine or switch off its breaker before any panel comes off — a capacitor can hold a charge after the power is off. Close the supply tap before touching a hose, expect standing water when a filter comes out, and never work round the door interlock.
When this is a service call rather than a reset
Call at once if water is escaping anywhere, if a supply-side safety device has triggered, or if the appliance fills when it should not.
Neighbouring codes on Bosch washing machines
What this page does not cover
This reading applies to the Bosch washing machine line as a whole, not to one family or model. It does not cover what differs between model lines — wiring colours, connector positions, part numbers and service-mode sequences — which are in your own model manual and which a technician matches to the rating plate rather than to this code. Where a family- or model-specific page for this code exists, it is linked from the code index below and it is the more specific answer.
Links: - [Bosch washing machine error codes](/blog/bosch-washer-error-codes)
Where to go next
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
