Tumble Dryer
F15
The F15 error code on a Siemens tumble dryer indicates a fault with the moisture sensor or drying cycle monitoring system — it’s a moderately serious fault that will prevent the dryer from completing a cycle, but in many cases it’s fixable without a professional.
What does this error mean?
Siemens tumble dryers use moisture sensor bars inside the drum to detect when laundry is dry and end the cycle automatically. The F15 code tells you the control board is receiving an abnormal or no signal from these sensors — either because the sensors are dirty, damaged, or there’s a wiring fault between the sensor and the PCB. On heat pump models, it can also relate to the humidity sensing circuit within the heat exchanger system.
Est. repair cost
£80–£180 professional repair; £15–£35 DIY moisture sensor part if self-replacing
🔍 Likely causes
🛠️ Step-by-step fix
Reset the dryer: Switch it off at the wall socket, wait 5 minutes, then power back on and attempt a new cycle. A software glitch will clear at this stage.
Clean the moisture sensor bars: Open the dryer door and look for two small metal strips on the inside of the drum, usually near the lint filter opening. Wipe them firmly with a cloth dampened with white vinegar or a small amount of rubbing alcohol to remove fabric softener residue. Dry thoroughly before running the machine.
Clean the lint filter and condenser: Remove and clean the lint filter — it should be done after every cycle. On condenser or heat pump models, remove and rinse the condenser unit (check your manual for its location, typically behind a lower front panel). A blocked condenser is one of the most common causes of sensor faults.
Check the drum for obstructions: Inspect the area around the sensor bars for trapped fabric or debris that could be bridging the contacts and giving a false reading.
Inspect the sensor wiring connector: If you’re comfortable doing so, pull the dryer away from the wall and remove the back panel (unplug first). Locate the moisture sensor wiring harness and check the connector is seated firmly. Do not probe or test live components — if you see burn marks, scorching, or broken wires, stop and call a professional.
If none of the above resolves F15, the moisture sensor or PCB will need replacing — this requires a professional repair.
📞 When to call a professional
Call a Siemens-approved or reputable local appliance engineer if the F15 error persists after cleaning the sensors and condenser, or if you find any damaged wiring. Tell the engineer you have an F15 fault code and that you’ve already cleaned the moisture sensor bars and lint system — this saves diagnostic time. A qualified technician can test the sensor resistance, check the wiring loom, and replace the PCB if needed.
⚖️ Repair or replace?
A professional repair for an F15 fault — typically a sensor replacement or PCB repair — costs £80–£180 in the UK including labour. If your Siemens dryer is under 5 years old, repair is almost always worthwhile. Beyond 8 years old, weigh the repair cost against a new mid-range Siemens or equivalent (£400–£700); if the PCB needs replacing on an older machine, replacement is usually the smarter financial decision.