Miele washing machine tripping electrics

[Googleit]

Hi, so I am after some advice regarding a Miele washer WKB120. Bit of a long post so apologies.

The other day something tripped the RCD, went round turning off and turning back on items to find the culprit and it was the washer. I have tested the machine from the plug with an insulation resistance tester and getting greater than 2000MO, plugged it back in didn’t trip straight away, seemed to be mid wash, started, drum turned slightly then tripped again.

So I suspected either the motor which is the induction type or heater (as mid wash my thinking was it might be trying to engage the heater.) Disconnected the motor and ran it, managed to cancel the program and drain the water. And didn’t trip. IR tested the motor and again >2000 so good and about 5.8ohms continuity through each of the terminals on the motor itself. Disconnected and tested the heater 25ohms continuity and 458MO to earth. Again I would think OK readings.

I decided to reconnect everything and try it again and now the machine seems to run fine, had it on an express 20 which ran through fine without tripping.

I have borrowed one of those plug in socket testers so did a test on that and the socket seems to be good too.

So basically any ideas on what could have been causing the tripping and why it now seems to have resolved itself?

[Googleit]

I also managed to lift the cover on the main PCB board to check there’s no burning/ charring and from what I could see looked in order. Don’t want to remove the board fully as it looks a bit involved with the wiring etc.

[electrofix]

its an earth fault that blows a trip and the main board is not earthed so it cant be that. yes if something had gone bang it may blow the trip but that would mean something would stop working and you have not got that

trips can blow for all sorts of reasons, including bad joints in sockets

so see how it goes and if it trips again try a different socket

assume you had no signs of water in the base

Dave

[Googleit]

Now you mention leaks where the door seal mounts onto the outer drum I could see signs of a small leak from there running down onto the heater shielding piece and into the base of the machine. Checked the seal for holes and didn’t see any so tightened the clamp ring on the drum a bit and that seems to have sorted it. I felt around it and there was a bit of moisture but nothing on the actual connections for the heater so can’t see as that had caused the tripping but maybe I’m wrong.

I’ll keep an eye on it, if it’s not that I can only think the socket is the problem as no earth faults were picked up on my megger.

[Googleit]

Update – ran a maintenance wash which was fine, then a relatively small load which was also fine. Put a big load of bedding in and it’s tripped again. Any ideas? Meggered it and again readings are perfect. Any ideas?

[electrofix]

check for your leak

Dave

[Googleit]

No leak anymore

[electrofix]

well it gets harder now

could be heater as some units only fail when hot

could be a faulty socket so try another one

does it trip when its washing or spinning
try to find out what its doing when it trips

Dave

[Googleit]

Indeed, really scratching my head over this one, the machine is full of water so must be mid wash when it went wrong. I did think heater like you said breaking down when hot however when I plug the machine back in and the heater must now be cold it turns the drum slightly then trips. Also I ran the maintenance wash on 90 degrees so if it was the heater failing you’d think it’d fail then.

I’m just wondering if the motor is failing with the heavier load?? but as I can’t pick up a fault on my meter I’m really not sure what else it could be.

I’m going to run an extension to another room on a different circuit and rule out a problem with the RCD.

[Googleit]

Worked a couple of washes on a different circuit and it’s doing it again, seems to be with the larger loads it fails mid wash. Does it sound likely that it could be the motor failing when turning the larger loads? It’s an induction motor so presumably should be quite reliable.

[electrofix]

have you checked wiring

heavier load means drum is lower, have you got wiring rubbed through anywhere ?

Dave

[Googleit]

Hi Dave, had a thorough look over the wiring again more carefully and you are correct, the heater wiring had rubbed through on the metal outer drum and with the larger load would throw the drum just enough to short out. I didn’t notice it last time as it’s hidden behind a metal reinforcement across the front of the machine and to be honest didn’t really expect it on a Miele. Repaired, rewrapped and clipped the wiring up so that it won’t happen again. Thanks for all the advice, much appreciated.

[Gokhk]

Thanks for the update nice to know your hard work paid off

[Author]

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