What F5 Means
WHICH MACHINES THIS APPLIES TO: F5 is used on the US T731 and T741 and on the TD73A and TD77A in the TD70 to TD77 range. Both families give it the same meaning, and two separate Asko documents say so.
US T731 AND T741 - WHAT F5 MEANS: the Use and Care Guide's error-message table reads, in full, "This indicates a problem in the moisture sensor. Running a dry program with dry clothes or an empty machine could also cause this error. Try opening the door. If the message remains, call a service technician." That middle sentence is the most useful line in the whole table, because it means F5 is not always a problem at all.
TD73A AND TD77A - WHAT F5 MEANS: the Asko Cylinda after-sales index prints F5 as "Problem in the moisture sensor". The supporting figures in the same document set the expected sensor output at 1 to 16 mV DC while the machine is running, and state that other values stop the program. The same section notes that a moisture sensor not installed in the fan casing, or a problem in the control unit, makes "the machine stops after ca 20 min".
HOW AN AUTOMATIC DRYING PROGRAM USES THE SENSOR: a sensor program does not dry for a set time. It runs until the laundry stops conducting, because wet fabric conducts between two metal strips in the drum and dry fabric does not. That is why loading a machine with laundry that is already dry, or starting an automatic program on an empty drum, can produce this code: the control asks for a reading that says "wet", gets one that says "nothing there", and treats it as a sensor that is not working.
WHAT YOU MAY READ ELSEWHERE: at least one repair site publishes F5 as a door safety switch problem and offers a mains reset as the cure. Two Asko documents - the T731 and T741 guide and the Cylinda index for the TD70 to TD77 range - both give the moisture sensor, and no Asko document assigns F5 to the door. If you arrived here holding the door-switch reading, that is where it came from and it is not supported.
CLASSIFICATION: problem, with a documented false trigger in front of it. The false trigger is common enough that Asko printed it in the consumer manual.
Common Causes of F5
- Automatic program started with dry laundry, a very small load or an empty drum, which is a documented false trigger rather than a problem
- Moisture sensor strips in the drum coated with fabric softener or detergent residue
- Moisture sensor circuit open or short, giving an output outside the 1 to 16 mV DC band the manual states
- Moisture sensor not seated in the fan casing, which the manual links to the machine stopping after about twenty minutes
- Wiring or connector between the sensor and the control unit
- Control unit problem
🔧 One Safe Check You Can Try
Start with the possibility Asko puts in its own table: was the load already dry, very small, or was the drum empty when you started an automatic program? If so, the code is the expected result and not a failure. The printed way to clear it is to open the door, which cancels the message; on the US machines you can also switch the power off and on. Then put in a genuinely damp load and run the automatic program again, and see whether F5 returns. If you dry small loads often, a timed program rather than an automatic one avoids the situation entirely, because a timed program does not ask the sensor anything. The other check that costs nothing is the sensor strips themselves: with the dryer switched off at the wall or the breaker and the drum cool, look inside the drum, usually at the front edge, for two metal strips. A coating of fabric softener or detergent residue across them insulates them and produces the same reading as dry laundry. Wipe them with a damp cloth and a little vinegar and let them dry. If F5 still appears with a wet load and clean strips, the sensor circuit or the control is to blame and that is where the owner work ends.
⚠ Why You Shouldn't Go Further Than That
- Wiping the sensor strips inside the drum is ordinary cleaning, but the dryer is switched off at the wall or the breaker and left to cool first, because the drum and the air behind it are hot at the end of a cycle.
- The sensor wiring and the control unit sit behind panels that also carry the heater and motor supply, which is live whenever the machine is connected to power.
- The millivolt figure in the manual is a running measurement taken by a technician with the machine energized and instrumented, which is not something to reproduce at home.
Opening a panel to inspect or repair something yourself doesn't automatically cancel your manufacturer's warranty — but it can risk accidental damage, and some manufacturers do have specific service conditions. Check your product's warranty terms, or ask us, before deciding.