Miele W4800 - Drain Fault

[MisterMoose]

With increasing frequency (but not every wash cycle), my Miele W4800 washer is producing a "Drain" fault/alarm and fails to complete the cycle, leaving me with a bunch of soaking wet clothes, and often a locked door. The machine is about 10 years old. I've cleaned the filter and verified that the pump impeller spins with some magnetic resistance. I've verified that the drain hose is not kinked.
When the fault occurs, there is a hum/buzzing noise that sounds like something is jammed. If I am present when the hum/buzzing starts, before the drain alarm sounds, I can consistently (100% success rate) correct the situation by tilting the machine forward (the back is about 3 inches off the floor) and letting it drop abruptly. When I do this, the buzzing stops, it sounds like the pump is working properly, and I can hear the water exiting the machine via the drain hose. If I gently tilt the washer forward and gently tilt it back, the problem does not correct itself, so I think that the jarring is what temporarily corrects the problem.
I am tempted to think that there is something on the exit side of the impeller that is jamming it, and that to correct this, I'll have to remove the panels and see if I can open the drain system and inspect it for debris. I don't really want to open the filter to check the impeller while there is water in the machine because I don't want to flood my laundry room. That said, I might decide to open it up (with water in it) when the problem occurs and hopefully be able to vacuum the water up with a shop vac before it floods the room.
Before I do anything, I thought that I would post here to see if anybody else has experienced a similar problem. Maybe it's a faulty sensor or something other then debris jamming the impeller?
Thanks for any help.

 

[MisterMoose]

So, I did a little more recon on the situation. When it faulted and stopped the cycle, I opened up the filter compartment to see if the pump impeller was jammed. It was not, so my theory of something jamming the pump impeller and preventing it from spinning is probably not correct. In addition, another time that it faulted, I managed to get to it before it shut down the cycle. I opened up the filter compartment and let the water drain out with the intention of checking to see if the pump impeller was stuck or not. The impeller started spinning on its own as the water was being drained out. I'm now starting to wonder if there is a float switch of some kind that may be sticking/faulty.

 

[MisterMoose]

Another observation is that the fault only happens on the final spin/drain. The washer drains at the start of the cycle, after the pre-wash, after the main wash, after the first rinse, then it crashes on the last rinse/spin cycle, unless I can catch it when it first happens and tilt/jar the machine to keep it going.

 

[RichardMNZ]

You may have a blockage in one of the breather pipes which run from the pump and from the under the detergent drawer to the top of the drain.
Remove the lid and behind the detergent drawer black hose running to the top of the anti-siphon unit.
Unscrew the cap. Is your one clean?

(Left of the orange inlet solenoid valve)
http://www.automaticwasher.info/TD/AWJPEG/MODERN/2012/vacfanatic++10-18-2012-19-15-36.jpg

 

[MisterMoose]

Thanks for the insight @RichardMNZ
I'll check this when I open the unit up. What really has me stumped is the "hummmmm" noise that the machine makes when the problem first shows itself. It will hum for a minute or so before the fault alarm sounds, and the unit stops the cycle. If I jar the unit before the fault alarm sounds, the humming stops, the machine works properly, and finishes the cycle. As an alternative to jarring the unit, draining some water from the filter port also causes the unit to stop humming and successfully carry on with the cycle. I have a feeling that this may be a multi-beer fix.

 

[MisterMoose]

@RichardMNZ, all of my breather tubes were clear, including the anti-siphon unit. I pulled all hoses off except for the one coming off of the base of the tub. No gunk other than a very thin film of slime in some spots. I'm tempted to think that it might be the pump motor that is starting to go. There might be a dead spot in the motor brushes.

 

[RichardMNZ]

What does the drain pipe connect to? Can water flow out of it easily?
When you hear the humming, if you put your hand on the pump filter can you feel any vibration (like the pump is going).

Have you tried the service menu to test the components?
On YT, there is a video titled Miele Touchtronic W3033, where they access the service menu.
On the component menu, the drain pump is M8.

The pump is also brushless.

 

[MisterMoose]

I replaced the pump motor. Fixed! I think that the impeller was slipping on the shaft. I didn't really verify this since I'd have to destroy the old motor to see if that was the problem... and I don't have time for that. I think that the hum that I heard was the motor running while the impeller was stationary. On a positive note, I was really impressed with how clean the filter and drain system components were after 10 years of use. No gunk to clean out, but I still rinsed everything with a mild bleach solution to freshen it up. There was a helpful (but not perfect) video on youtube that gave me enough information to be able to take the W4800 apart. It showed the sequence of which parts to remove first: lid, control panel, door seal, front panel, then side panels. If I ever have to open the unit up again, I might strap my GoPro on and make a better video to post for others to use. Having never worked on the W4800 before, the trickiest parts for me on this project were:
1. Removing the lid. After loosening the side screws, I initially did not push the screws in which is necessary to release the catch mechanism.
2. Removing the control panel cover. The plastic of the cover as well as the plastic of the bracket that frames/retains it are both brittle in my opinion. I ended up using a thin metal spatula to pry and flex the bracket away from the panel so that it could be popped out. Luckily, no damage was done. The yellow/orange plastic wedge tool that comes with the unit would probably work to remove the panel, but mine is broken.
3. My machine has the "upgraded" door seal kit, which means that it does not have a spring clamp on the outside of the door seal. Instead, it has a ring that ratchets together. It's difficult to see how to release the ratchet mechanism. Miele technical service would not tell me whether it was a single-use clamp or whether it was designed to be removed. A little twisting pressure with a flat screw driver inside of the ratchet mechanism releases it.

Hopefully, this final post helps others in the future.

Moose-out!

 

[bpowell555]

Hi, out of interest did u replace with miele original pump or espares cheap version?

Cheers!

 

[MisterMoose]

Hi @bpowell555
I had a Miele tech come in and replace the pump with a Miele part.

 

[bpowell555]

Thanks for the reply

Turned out was not pump noise but fan noise in the blower/condenser on mine.