Washer dryer f13 error – a tale of diagnosis and repair

Our Hotpoint Ariston AQD1070D-69 washer dryer runs a heavy schedule in this house. The last few days was more noisy than usual, especially while the centrifuge was running. Then, the machine stopped with a massive display of blinking LEDs and a «f13 error» message. Panic ensued at family management, as the ever-flowing stream of laundry suddenly started to pile up. A swift repair was required.

This is the story of my repairing this machine, which might be useful for diagnosing a handful of related faults. Part numbers etc. mentioned will be specific to the AQD1070D-69, but the principles I’d guess applies to many if not most such washer dryers.

Searching «washer dryer error f13» immediately suggests a faulty temperature sensor in the hot air (dryer) channel. This channel runs on top of the drum, and is accessible by taking off the top cover (undo two screws at the rear). The aluminum channel consists of one upper and one lower part, screwed together with 6-7 torx screws (t20) and a gasket inbetween. Take off the top part of the channel, and this exposes the temperature sensor (part C00290251) which sits in front of the heating element, next to the air fan (the motor and fan is fixed to the top of the air channel).

There are some good videos available that shows how to access the sensor: here and here (although I guess you’ve already found those videos before finding this page).

Now unplug and take out the culprit, i.e. the temperature sensor. But is it really at fault? It is stamped 20K, meaning it’s nominally 20 KOhms at 20 degrees celcius, and less with higher temperatures. Measure its resistance (two small alligator clips worked well for me) at room temperature and in a cup of hot water. If the values are not reasonable, replace and reassemble. But mine seemed to report perfectly fine temperatures, so it was unlikely to be the real problem.

This means that for some reason the temperature in the hot air channel is outside the range of temperatures the brainbox expects. So either there is no heat (too cold) or there is no airflow (and so too hot). Which it is can be checked by running a washing cycle without the top cover and feel the temperature of the air channel when the f13 error comes on. (I didn’t do this at first.)

Next in line is the heating element. Measure the resistance over its two terminals. I don’t remember the exact value, but it should measure a handful of ohms. Also inspect the element visually that it’s not broken. You can also power up the heating element, if you’re comfortable with power electronics, but if resistance and visual inspection is OK, the heating element is likely fine, as mine was.

Now for the fan. At this point, the problem is likely to be too high temperature, which can only be from insufficient airflow in the channel. (Again, this can be verified by running a wash dry cycle.) Easiest check I believe is to hook it up to power and see if the fan runs. A wall plug connected to spade connectors is useful for this. As are the usual precautions with exposed power electrons. If the fan won’t run, it must be replaced. My fan ran fine.

Now, the fan moves air coming from the drum through a plastic channel running down behind the drum. If something blocks airflow, no air and so no heat will be moved. So we’ll remove and inspect this plastic channel. First, remove the lower part of the aluminum air channel, fixed with 4 or 5 larger torx screws (t27 I think). Also remove all the electronic connectors to the fan and heater element, and the two relevant water pipes. Take off the rear panel for access. The translucent plastic channel is fixed with large hose clams both on top (to the aluminum air channel) and bottom (to the drum). The upper hose clamp you don’t need to loosen for removal (the screw is difficult to access under the aluminum channel), but the lower hose clamp must be undone with a long screwdriver from above. It’s a tight fit, but the plastic channel can now be removed. Clean it out. Mine was dirty, but not overly so. Also, there is a green plastic filter where the plastic channel attaches to the drum. This might be where airflow is blocked. Take it out and clean it. Mine was quite dirty, but I wouldn’t think it should block airflow completely.

Now, reattach everything. Almost everything that should theoretically be able to cause the f13 error has been inspected and verified, so it is time to run a cycle and see if the problem persists. Well, in my case, it did persist. Quite peculiar.

When the f13 error now appeared, I did notice that indeed the aluminum air channel was extremely hot to the touch. That must mean that air is not moved properly. But I checked the fan already, and it ran fine!?

Running another dryer cycle, looking carefully at the fan motor spindle that is just visible, I could see that the fan was in fact not running. I pulled off the top of the air channel with the fan, so I could test-run in once more. And once more the fan ran just fine. This suggested something was hindering the fan from turning when it is mounted in position. The obvious suspect would be the heater element which is located right nest to the fan. But why would the heater element suddenly start touching and blocking the fan’s movement?

It was at this moment I connected the dots: The excessive noise we’d been hearing from the machine the last few days, was in fact the sound of the heater element being shaken and stirred inside the aluminum air channel. And sure enough, at closer inspection there was a small metal bracket broken off at the far end of the heater element, no longer holding it securely in place. Consequently, the heater made a loud noise when the machine was shaking from the drum running at high speed, and it also blocked the fan from running, causing zero airflow and so much too high temperature in the air channel (and no heat in the drum), triggering the f13 error.

In the picture above you can see the heater element, fixed with a new bracket (at the extreme right of the element) that I made from some sheet metal.

Now, reassemble everything, and enjoy a silent, error-free machine that dries your clothes somewhat more efficiently than before, due to the cleaned up air channels and filter.