Bosch WFF 2000 – Trips RCD of Mains Elec

[Gavin Edwards]

The RCD of the mains electric trips out when washing with our Bosch WFF 2000. Some washes seem to go through ok, but on others the RCD will trip out a number of times per wash cycle.

The house electrics have been checked out by a qualified electrician – all are ok. On his recommendation I changed the heater element, but unfortunately, the problem still persists.

I did notice, however, that there is a thin black film coating much of the inside of the machine. The black substance wipes off easilly, especially from the plastic areas and insulation. Don’t know if that is significant.

Any ideas, please? Cheers. Gavin

[gegsy]

Re: Bosch WFF 2000 – Trips RCD of Mains Elec

Hi
The black stuff is motor carbon dust. This stuff is electrically conductive so if it gets where it shouldn’t will cause problems.
I would start by removing motor, check brushes and replace if necessary.
Remove as much of the dust you can from the motor itself as it could be tracking over and causing the fault you have.

Power off first before attempting :plug:

Greg

[Gavin Edwards]

Re: Bosch WFF 2000 – Trips RCD of Mains Elec

Thanks for the advice; makes sense about the arcing. I will try to clean it off. Is it possible that it has got into the inner workings of the controller or other sensitive parts?

One thing I didn’t say though was that when the power does trip it seems to happen at the same point in the wash part of the cycle – near the beginning of the main wash – particularly on the 60 deg C or above washes. Does this indicate a more specific issue?

Thanks, Gavin

[gegsy]

Re: Bosch WFF 2000 – Trips RCD of Mains Elec

Sounds more like a heater problem TBH 😕
With a suitable meter (megger) you can check for breakdown of the heater.
Power off first 😥

Greg

[Gavin Edwards]

Re: Bosch WFF 2000 – Trips RCD of Mains Elec

Thanks Gegsy. Problem is I just replaced the heater element yesterday. Is it likely that it (genuine part) would be defective on fit?

Have cleaned off all the carbon from the exposed wiring and terminals. Is it possible to get access behind the control panel? There imust be carbon behind there as it has come through to the programme dials behind the perspex.

Cheers, Gavin

[gegsy]

Re: Bosch WFF 2000 – Trips RCD of Mains Elec

You can get earth leakage on new elements, had it myself.
Only a suitable meter as mentioned will confirm for you.
Ive never had problem with carbon dust in the module TBH, but in saying that its not impossible.

Greg

[Gavin Edwards]

Re: Bosch WFF 2000 – Trips RCD of Mains Elec

Thanks again Gegsy. Will see if I can get it tested tomorrow and will let you know.

In the interim, how easy is it to get access behind the control panel?

Cheers. Gavin

[Penguin45]

Re: Bosch WFF 2000 – Trips RCD of Mains Elec

3 screws round soap drawer opening, the lever panel off with flat-bladed screwdriver – gently…….

Penguin45.

[Gavin Edwards]

Re: Bosch WFF 2000 – Trips RCD of Mains Elec

Problem well and trully solved! A very good steer on the carbon-dust film which was definitely the source of the problem.

I cleaned everything I could. Took about 2 hours to do: unclipped all wiring and disconnected every electrical connector in turn and wiped them down with sheets of kitchen towel before reconnecting them. Then wiped down the surfaces and anything else I could get my hands on. Found evidence of tracking across 2 pins on at least one connector. I guess this could have been enough to provider the mAmps needed to trip the RCD.

Since had about a 20 washes including 5 x 90 deg C service washes and 8 at 60 deg C all without power tripping. Fantastic. Thank you very much for your advice. :worthy: 😀

Gavin Edwards

PS. Do you think the buildup of carbon-dust film is normal over a period of time or is this an indication that the brushes have broken down and need to be replaced?

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