Miele T 294 C tumble dryer

[shoz]

Right, I hope I am on the correct thing here. If you look at the picture of the connector with 4 terminals the 2 connections to the left had brown wires attached and the 2 to the right had light blue wires. If you number those terminal 1, 2, 3 and 4 then I could get no reading between terminals 1 and 2 and no reading between terminals 3 and 4 but when I tried terminals 1 and 3 I got a reading of 5.3 ohms and a reading of 14 ohms between terminal 2 and 4 which is not what I expected. I thought it would be adjacent pairs that should have a resistance or am I completely wrong?

Untitled

• shoz
• 18 Jul 2012
• 1

from left, 1, 2, 3 and 4

 

[zipper]

Errmm...that's the mains suppressor.
The heater pcb is in the white plastic case to the right of it.

 

[shoz]

ooops, proves what I know about dryers

Will look again tonight, from what I can remember there were quite a few wires on that.

 

[shoz]

Untitled

• shoz
• 20 Jul 2012
• 1

Ok, let's see what sort of mess I can make of this.

You said 2 thin wires and 2 thicker wires. The picture shows a pale blue connector to the left with 2 white, thick wires with a coloured stripe woven into the insulation. The resistance at this plug was 92 ohms. To the right of the picture is a white connector with 2 light grey, thin wires. The resistance at this plug was 148 ohms. I hope that makes sense.

 

[zipper]

The element is ok.
Are you sure the two thin (NTC) wires measure 148Ω & not 148kΩ?
Because if it measures 148Ω it is shorted. Check your meter settings & report back.

 

[shoz]

Yes, you're right, it should have been k ohms. The actual reading this morning was 139.7 k ohms but the dryer had been on a cool cycle. This is the reading at the plug and not the pcb, hope I am measuring the right one.

 

[zipper]

Ok. How old is this machine BTW?
I suspect the front NTC is defective. Before we go any further put the machine in service mode by doing this...Switch off, close the door, & turn the program selector to finish. Press & hold in the start button & switch on (still holding in the start button). As soon as the start LED lights up release the start button. Immediately press & release it 3 times, but on the 3rd press hold the start button in until the start LED flashes slowly. Release the start button. If successful the start LED will keep flashing at 1hZ. Turn the program selector to position 1 & watch the drying LED. It should blink in a repeating sequence of long or short flashes (or a combination of both). This represents a specific error code. Note the sequence & post it here.

 

[shoz]

The dryer is coming up to 5 years old.

The sequence of flashes is -

drying led is 4 quick flashes then approx 2 second gap the repeat 4 quick flashes etc etc

cool air led 1 flash approx every 2 seconds

 

[zipper]

Call Miele spares on 0845 365 6605 & order P/N 3523184 (temperature sensor K276/12K/A21). This is the front NTC & to get at it you'll have to remove the kick strip & lid, then remove the front panel (ca: 8 - 10 T20 screws). You will see the NTC at the bottom left once the front is off. It has a plug connection with 2 thin black wires. The NTC retails at around £60.

 

[shoz]

Thanks, I will get one ordered and let you know the result.

 

[shoz]

The good news - sensor arrived and fitted this morning

The bad news - it made no difference, the alarm sounds just as before. I took the resistance of the the sensor I removed and it was around 13 k ohms which gradually reduced as it warmed when I held it.. The new one started off around 14k ohms with the same sort of reduction in resistance.

 

[zipper]

The sequence of flashes is - drying led is 4 quick flashes then approx 2 second gap the repeat 4 quick flashes etc etc

That equates to error F4 which signals a open circuit front NTC. As you have changed it now with no difference I would suggest checking the continuity of the NTC cables back to the main pcb (remove the plug & check there is continuity on both cables then re-seat the plug firmly). If that doesn't help go back into service mode to where you read the error code. At this point press & hold the start button for min 5 secs to delete the error log. Then run a new cycle, if it gives an alarm go back into service mode & post the sequence of flashing lights as before.

 

[shoz]

Will try all of the above asap.

Is the front sensor the same as the rear one? Are they interchangeable in case it's the rear one that's faulty?

Will the heater element be ok?

 

[zipper]

No the front & rear NTC are very different. Looking back through my answers on the thread I see I mistakenly posted the wrong resistance for the rear NTC earlier. I said it should be 14kΩ but of course I missed off a digit & it should have read 140kΩ. You measured 148kΩ which shows it is around ball-park resistance at room temp. But try warming it up in a cup of boiled water & check if the resistance drops rapidly to around 12kΩ. If the rear NTC had failed you ought to have seen the drying LED repeatedly flash twice (F2) & not 4 times (F4) as you did. I think we can safely rule out an element issue.

 

[shoz]

Sorry for the delay in replying but it looks as though we might have got the gold medal at long last.
I did all the checks you said, removed all connectors and then put everything back together and since then everything has worked fine. Maybe when I put the new sensor in I didn't push the connector fully home.
Many, many thanks for your help and if you ever get near Turriff I'll get you a pint or a wee dram.

Thanks