Dryer Full of Dust? - A service guide - Miele Tumble Dryer

[dishman]

I got given a rather good miele tumble dryer model T7934 -

The previous owner was "upgrading" to a integrated heat pump variety.

The problem was, they did not really look after this thing properly. They rarely cleaned the lint filter or checked/cleaned the seals.

This resulted in dust making it past the lint filter and basically collect in areas of the dryer it should not collect. I suspect many people use their dryer in a similar fashion.

So this is an example for people to show all the crap that will slowly clog up your dryer if you do not maintain it.

Serving a modern machine like this is seemingly a pain. So do not let it get to this stage!

This could also end up being a fire risk. If a lot of dust makes it to the motor or a poorly designed heating element, it could be at risk.

Step 1 - Inspect the dryer


Step 2: Remove the screws at the back that secure the top via a detachable hinge.



Step 3: Remove the caps down the sides of the top. You will need good nails or a slim/sharp flat head screwdriver. Remove the screws.



Step 4: Remove the Top to reveal the innards


Take note of the armature that connects to the drum. This is Miele's moisture detection system. It apparently passes a small current through the drum which is passed through those tracks and through the armature to a sensor.



The armature supports two carbon brushes which make contact with the tracks. These slowly wear down over time. When the carbon brushes are worn away, the armature begins to catch the drum once every rotation. This may make the dryer sound like the bearings are going. They are not!! You just need to replace the carbon brushes. These cost £20.

Also note the huge amount of carbon dust deposit. I found this everywhere inside.

Seems like you over engineered this Miele!

Continued in Post 2

 

[dishman]

Step 5: Before you can remove the sides, you have to remove the front.
The front comes off in one big unit with door attached. So you need to remove every visible screw on the front panel. Including the door hinge screws. These do not hold the hinge on directly, so the door should not fall off.



You can see the two screws I have left.

Note the signs of all the dust clogged in areas it should not be:



Also note the damaged door seal




Step 6: - Remove the front and then access the side panel screws and remove them. The control panel also lifts up as it just slots into the door. Remove this and rest it on top. You can detach this, but it means disconnecting all the circuit connections. I did not bother.

Just ensure there is no tension on the wires otherwise they could pull out the connections to the circuit board. I recommend taking a photo of the board just in case.



Step 7: Inspect

 

[dishman]

Inspect more:


As you can see, there is a lot of dust that has found it's way out of the pipe work and into the machine itself, around the motor, on and around the drum. Whether this is because of the environment it was used in, or poor maintenance has caused it to escape, it needs to be cleaned. It should not be there!

Dust in the pipework is more explainable, but again, by cleaning the lint filter regularly, and ensuring the seals are clean around the door, it should minimise this much collecting.


Step 8: There is still one more place to check.

This is the compartment under the door, it was chock full of dust and is hard to access from the door itself. It also connects to the fan impeller. This should be inspected.



To do this you need to remove two larger screws on the front. One is just below the drum and is at the bottom of a hole. It is not visible from the surface. The second is at the bottom right and connects to the motor housing.

These two screws hold the front drum surround on.

I found this easier to do with the machine on its back on the floor. This also means the drum is not supporting it's own weight when you remove it.

So lie the machine on it's back

 

[dishman]

Once it is on it's back.


Unscrew the retaining plate that was supporting the control panel. It has four screws and then lifts off. Once you have removed this, the front surround and ducting compartment can be removed.

Jiggle it and lift it off. It is kept on by hooks at the top corners.

Step 9: Inspect the revealed areas:

Just look at all that inaccessible dust and crud.



Step 10:

Start cleaning!

Vacuum all the dust with a wand and brush. All this dust completely filled a bag.

Then use a wet microfibre cloth to clean out all the pipe work. Clean any rubber seals. Do not use washing up liquid on rubber seals (it is not good for them).



To be continued!

 

[dishman]

Step 11:

Next I had to deal with the door. This contains the lint filter. This is one of the problem areas. If you do not empty the lint filter regularly, the lint will get stuck in the door, fall down and get pushed into areas it should not go. Basically the lint/dust should not make it past the door. Or this happens!



As you can see, the slot is too small to clean. So you have to take the thing apart.

To do this, you need to remove the front which is held on by plastic tabs. I used a plastic knife to prise it off....

Voila!


Then - remove the hex screws, and all the component pieces come come apart.



These need to be cleaned.

The lint filter itself was also clogged with dust. This had to be soaked to get the dried in dust out of the mesh, otherwise a lot of airflow would reduced.

 

[dishman]

Step 12

Next I checked the rear of the machine where the heating elements are housed.



I decided to remove it just to give it a quick check. I found yet more dust:



I also found that dust had collected behind the drum where hot air enters the machine.



I did not really want to do this, but I decided to remove the actual drum. As there was a lot of dust back there, and if I was going to give it a good service. I may as well do it properly....

Unlike many dryers from the guides I have seen on youtube about, the drum is not held in place by any supports other than the front door housing. Once the door housing is removed it has no other structural support except the rear bearing connection. So I strongly recommend doing this on it's back.

Ideally you could put it on a frame to work on it from underneath. I just propped a chock under it and worked on it at an angle.

I removed the small plate you can see in the picture above which revealed a small plastic latch which seemed to lock the drum to the frame.

This is all that held it in place so it would be tempting fate to try this upright. It would put a lot of pressure on that latch.

Once the latch was turned 90 degrees the drum was released...

This is what found:



So, it did require this....a quick clean and....

 

[dishman]

Step 13 -

Put all the main components back together.

The hardest part was getting the drum seated and getting the plastic latch to turn 90 degrees and lock. It has no groove in to use a screwdriver. I ended up having it in the lock position and screwing the rear retention plate on after.

Putting the belt back on was not as hard as I imagined.At first I was using a lot of force but then realised the motor was spring mounted. So I could pull the motor up to meet the belt.

Once all back together. Inspection time


Nice and clean!

 

[dishman]

Step 14

I was still concerned about amount of dust in the heating element unit.



I forgot to take a picture of the dust from the other side, but there some on and in the heating spring/coils at the bottom. You can just about see it.



So I vacuum the easy bits.
Then attached a straw to the vacuum hose. This allowed me to carefully suck all the dust off the heating elements inside.



And around the thermostat.

Before

After

Then inspect the rear again. All the dust now gone..

 

[RichardMNZ]

Great work. I wonder what the ducting in the house looked like.
This is what needs to happen to all dryers after some years.

We have a Miele dryer and although the filters are cleaned regularly dust still gets past them.

I hope you enjoy a fantastically well built machine.

Richard

 

[dishman]

I can confirm that it was connected to a flexihose which was chock full of dust when I last saw it.

What is interesting, looking at where the airflow tracks on this machine is that air is drawn in from the free space inside and from under the machine.



So there will be a vacuum like suction that draws air in from the bottom (open floor) of the cabinet. This is probably one reason why the interior got so full of dust and crap.

Why they do not design an inlet hose with a quick removable mesh filter, I know not.

I will be posting the final stages and reassembly soon.

 

[dishman]

Step 15:

The next thing I decided to look at was the inner opening seal/gasket. As you can see in the picture I took earlier, it has small but significant damage to it. This was in the 6 o'clock position on the door. Presumably too much was put in and an item of clothing got trapped in the door. As it twists during the cycle it tore off a piece.

It is also vulnerable wear and tear from stuff being pulled in and out in this position.



Looking at a straight replacement, the cost was around £60-80 !!! I think not!

Other than this small tear, it was otherwise in good condition.

One option was to just rotate it around 180 degrees so it was at the top. However, if the seal is compromised, unwanted dust and airflow would make it past. So I decided to attempt a repair.

After looking at options, bathroom sealant seemed the most appropriate material. It should dry but still have a strong flexible quality to it. Silicone is heat resistant and the bathroom variety has mould resistant properties for damp areas.



After making a mould using some card and tape and cling-film, I filled it in like cake icing using the flat end of a screwdriver.



As it was still a delicate repair I decided to cover a larger area for further support and create smooth the leading edge so it was flat. As you can see, there is an indentation down one side before this was done.



I even managed to shape it into a channel on the underside.




Success!

I shall still rotate it 180 degrees when fitting. This means the repaired/vulnerable area will be located at the 12:00 position where it is less likely to suffer constant wear and tear.

 

[dishman]

Step 16:

Reassembly Time!

Starting with the door.....



Re-attach the rubber gasket around the lint filter holder. Then just 5 screws to put it back together. The vanity front just snaps back on after aligning it.

Next, ensure that when re-attaching the front retention plate for the front door/drum support you also connect the door release cable. This is similar to a bike break cable. It hooks in to a plastic retention keep.

 

[dishman]

Step 17: Re-assembly

There are a number of different screws for this machine, so remember to make a note of what screw was used where. I nearly forgot to do this but I could use the photos and a process of elimination.



So now I had to re-attach the side panels.

Before doing this I had to ensure I slotted on the frames for the vent outlets first. It has three outlets available on each side for ease of vent pipe positioning. The two you do not use have caps that screw into a small frame. So ensure you put the frame on before putting the sides!

Attach the side panels and screw them to the frame. Then, attach the front panel.



Next I decided to insert the repaired gasket. I rotated it roughly 180 degrees from it's old position so that the repaired/vulnerable section was out of the way of daily wear and tear.



As you can see, it worked out great.


Looking down from above it looks like a brand new seal.

 

[dishman]

Step 18:

Finish.

So, now I had to connect the door, which hooks on and then screws in.



Slot the control panel into it's slots, no screws required.



Then the vent passage inserts.



Pop the top cover back on - don't forget the screws and caps down the side:


And then give the machine a clean.



Job Done!

I have to final things to do.

1. Replace the lightbulb which illuminates the interior and the doorway when collecting laundry.

This normally has a 15w incandescent. However, I have ordered a 2.3w (20w equivalent) Cool White LED bulb of a similar size which should fit and will give out a much better quality light.

2. Replace the carbon brushes. As this machine is very automated, they seem to be a requirement for proper operation. So a replacement will be ordered and fitted. These cost £19 for what seem to be a genuine replacement for a reputable supplier. Buying these direct from Miele will cost a lot more.

I will update the post when these final things are done!

 

[RichardMNZ]

Yes please. Details on where you bought the replacement brushes and bulb from please. The recommended bulb is too weak and its good to know where to get replacement brushes at a good price.
Richard