Tumble Dryer
F02
The F02 error code on a Siemens tumble dryer points to a problem with the appliance’s NTC temperature sensor — the component responsible for monitoring heat inside the drum. While it can sound alarming, this fault is often caused by something straightforward like a blocked condenser or a minor wiring issue, and in many cases you can resolve it yourself without calling out an engineer. In this guide, we’ll walk you through exactly what the F02 code means, the most common causes specific to Siemens dryers, and a safe, step-by-step process to diagnose and fix it.
What does this error mean?
The F02 error code on Siemens tumble dryers — including popular heat pump and condenser models in the iQ300, iQ500, and iQ700 ranges — indicates that the NTC sensor (Negative Temperature Coefficient thermistor) has either detected a temperature reading outside the expected range, or has stopped sending a signal to the control board altogether. In plain English: the dryer’s brain can no longer accurately read the temperature inside the machine, so it shuts itself down as a safety precaution rather than risk overheating your laundry or damaging internal components. This is a protective fault, not necessarily a catastrophic failure. The dryer isn’t broken beyond repair — it’s telling you something needs attention before it can safely continue.
Est. repair cost
DIY NTC sensor replacement: £10–£25 for the part. Professional repair (sensor, wiring, or heating element): £80–£180 including call-out and labour. PCB replacement by an engineer: £150–£300.
🔍 Likely causes
🛠️ Step-by-step fix
Step 1 — Reset the dryer: Switch the dryer off at the mains, leave it unplugged for 5–10 minutes, then plug back in and power on. A temporary sensor glitch or control board hiccup can sometimes be cleared with a full power reset. If the F02 code reappears immediately or on the next cycle, move to the next steps.
Step 2 — Clean the fluff filter: Pull out the lint filter (usually located inside the door rim) and remove all built-up fluff. Rinse it under the tap if it’s coated in fabric softener residue, and let it dry fully before replacing. A blocked filter is the single easiest cause to fix and should always be your first check. No tools needed.
Step 3 — Clean the condenser unit: On condenser and heat pump Siemens dryers, locate the condenser access panel (usually at the bottom front of the machine). Unlock the fasteners, remove the condenser, and rinse it thoroughly under a cold tap until the water runs clear. Allow it to dry fully — at least 30 minutes — before refitting. This is one of the most commonly overlooked maintenance tasks and a frequent trigger for F02.
Step 4 — Check and clear the water tank (condenser models): If your dryer collects condensed water in a removable tank, empty it fully and rinse the tank out. A full or blocked tank can interfere with the moisture and heat management system, sometimes contributing to temperature sensor faults.
Step 5 — Inspect the exhaust hose (vented models only): If you have a vented dryer, check the flexible exhaust hose for kinks, blockages, or a crushed section. Disconnect it from the wall vent and look through it — it should be completely clear. Replace it if it’s damaged; a new exhaust hose costs around £5–£15 from any appliance spares retailer.
Step 6 — Check you’re not overloading the drum: Refer to your Siemens dryer’s manual for the maximum load weight for your specific programme. As a general rule, a full load should tumble freely — if clothes are tightly packed, remove a third of the load and run a test cycle to see if the fault clears.
Step 7 — Visually inspect the NTC sensor wiring (only if comfortable doing so safely): With the dryer unplugged from the mains, remove the back panel of the dryer (you’ll need a Torx or Phillips screwdriver depending on your model). Locate the NTC sensor — it’s a small component clipped to the heating duct or drum outlet, connected by a two-wire harness. Check that the connector is firmly seated and that the wires aren’t visibly burnt, corroded, or broken. Reseat any loose connectors gently. WARNING: Only do this if you are confident working around appliance internals. If in any doubt, stop here and call a professional.
Step 8 — Test or replace the NTC sensor (DIY-confident users): The NTC sensor can be tested with a multimeter set to resistance (Ohms). At room temperature (around 20°C), a healthy Siemens NTC sensor typically reads approximately 10,000–12,000 Ohms. If it reads open circuit (infinite resistance) or zero Ohms, it has failed and needs replacing. Replacement Siemens NTC sensors are available from UK spares suppliers such as eSpares, 4ourhouse, or Siemens-branded parts stockists, typically costing £10–£25. Fitting is straightforward — unclip the old sensor, connect the new one, and reassemble.
Step 9 — Run a test cycle: After completing any of the above steps, run a full drying cycle on a medium heat setting with a small load. Monitor whether the F02 code returns. If it does not reappear over 2–3 cycles, the fault has been resolved.
Step 10 — If the fault persists after all of the above: The fault is likely with the NTC sensor wiring harness, the heating element, or the main PCB — all of which require professional diagnosis. Stop DIY attempts at this point and book a qualified appliance engineer.
📞 When to call a professional
You should call a qualified appliance engineer if: the F02 error returns immediately after a full reset and the condenser/filter are both clean; you’ve replaced the NTC sensor and the fault persists; you notice burning smells, scorch marks, or the dryer is unusually hot to the touch on the outside; or you’re not comfortable removing the back panel or working near internal wiring. When you call, tell the engineer: ‘My Siemens tumble dryer is showing an F02 error code. I’ve already cleaned the condenser and lint filter, performed a power reset, and [add anything else you’ve tried]. The fault is still present.’ This saves diagnostic time and can reduce your call-out cost. Look for an engineer who specialises in Siemens or BSH Group appliances (Siemens, Bosch, and Neff all share common parts and platforms), as they’ll have the most relevant experience and are more likely to carry stock parts.
⚖️ Repair or replace?
If your Siemens tumble dryer is under 5 years old, a professional repair almost always makes financial sense — Siemens is a premium brand and a well-maintained machine should last 10–15 years. If the fix is a new NTC sensor, you’re looking at a modest parts and labour cost well below the price of a new machine. If the fault turns out to be the main PCB (control board), costs rise significantly — typically £150–£300 including parts and labour. At that point, weigh it against the age of the machine: if it’s 8 years or older, a PCB repair on an ageing dryer may not be the best use of your money, and upgrading to a new A-rated heat pump dryer (which will save on energy bills) becomes a more sensible option. New Siemens condenser and heat pump dryers currently range from around £400 to £900+ in the UK, depending on the model and retailer. If your machine is 5–8 years old and the repair is for the NTC sensor or wiring only (under £120 all-in), repair is clearly the right call. If it’s the PCB on a machine over 7 years old, replacement deserves serious consideration.