Tumble Dryer
F15
The F15 error code on a Bosch tumble dryer indicates a fault with the appliance’s moisture sensor or its associated wiring, preventing the dryer from accurately detecting when your laundry is dry. It’s a moderately serious fault — the machine may still run, but programmes will be unreliable and clothes may come out over- or under-dried.
What does this error mean?
Bosch tumble dryers use two small metal moisture-sensing bars inside the drum to measure how damp your laundry is as it tumbles. The F15 code means the control board is receiving an abnormal or absent signal from these sensors. This could mean the sensors are physically dirty, damaged, or that there’s a wiring fault between the sensor and the main PCB.
Est. repair cost
£80–£150 for a professional repair; moisture sensor bars cost £10–£25 as a DIY part if you are confident and competent
🔍 Likely causes
🛠️ Step-by-step fix
Reset the dryer first: unplug it from the mains, wait 10 minutes, then plug it back in and run a short cycle to see if the error clears.
Locate the moisture sensor bars — they are two parallel metal strips, usually positioned just inside the drum opening below the door seal. Clean them thoroughly using a soft cloth dampened with white vinegar or a mild descaler, then dry with a clean cloth.
Check the drum seal and door area for any obvious damage or debris that might be preventing proper drum rotation or sensor contact.
Reduce your load size to no more than three-quarters of the drum capacity and re-run the cycle. Overloading can cause persistent sensor misreadings that trigger the fault.
If the error returns after cleaning and resetting, visually inspect (without opening any panels) for any visible loose or burnt wiring near the door hinge area — if you spot damage, stop and call a professional.
If none of the above resolves the fault, the moisture sensor bars or the main PCB likely need replacing — do not attempt to open the rear or side panels yourself; book a qualified engineer.
📞 When to call a professional
If the F15 error persists after cleaning the sensor bars and performing a reset, call a Bosch-approved appliance engineer or a reputable local white goods technician. Tell them you have an F15 fault code, that you’ve already cleaned the moisture sensors, and ask them to check the sensor wiring loom and main PCB. Do not attempt to open the machine’s panels yourself — internal wiring carries mains voltage and must only be handled by a qualified engineer.
⚖️ Repair or replace?
A professional repair for an F15 fault — typically a sensor replacement or wiring fix — costs around £80–£150 in the UK including parts and labour. If your Bosch tumble dryer is under 5 years old, repair is almost always worth it; Bosch machines are built to last 10–15 years. If it’s over 8 years old and the PCB needs replacing (£120–£200+ for parts alone), weigh that cost carefully against a new mid-range condenser dryer at £300–£450.