Hoover W1120 washing machine short circuit

[spinynorman]

Hi, as I closed the door of my Hoover W1120 washer I noticed that the earth leakage switch on my fusebox had tripped. I hadn't even selected a program or turned the machine on. The fault is now present whenever the machine is connected to the mains, with all controls 'off', regardless of whether the door is open or closed.

Everything appears normal under the lid. I did some basic checks and discovered that the fault is on the live circuit. The live input goes to a terminal on the pressure switch. Disconnecting that terminal, not too surprisingly, stops the problem so it's somewhere further along the circuit.

On the possibility that closing the door had caused a slight pressure change in the drum and activated the pressure switch I looked inside the switch but saw nothing wrong, with no evidence of burnt terminals and the diaphragm in good condition. When blown into, the switch makes two clicking sounds a second or so apart and the same when the pressure is released, consistent with the two internal switches being operated.

The fault conditions have now changed. The washer can now be left connected to the mains but as soon as I move either the dryer or program knobs the short occurs, even before I use the 'on' switch. The washer worked normally when used a few days ago.

Any further clues appreciated

 

[jj4091]

If you do not have a multi-meter that you can use to test for a short to earth then your only option is to disconnect components (waste pump, heater element, motor, etc) until you find the one that is causing the problem. Ensure that any bare terminals on disconnected wires are well insulated with tape before reapplying the power.

 

[spinynorman]

Thanks, that's what I've been doing this afternoon.

I had a similar problem nine months ago. At that time I took the pump out and found a significant amount of lint inside. It seemed to work ok after cleaning so I refitted it and it worked fine for the next three washes before shorting again. I bought a new pump (Plaset) and all's been well since then.

This time there didn't seem to be causal link between the pump and the first short which occurred when I shut the door yesterday but I disconnected it anyway and the short was fixed. On examination the pump had the tiniest amount of lint which couldn't have caused any resistance to turning.

It didn't turn smoothly by hand but I powered it through a temporary cable and an RCD and it seemed to spin at a reasonable speed. I then connected a meter across the terminals whilst slowly rotating the fan and saw readings of around 180 kilohms with occasional drops to 0.

Just to prove it wasn't a fluke, I connected it back on the washer, expecting it to short again but it didn't. It has just completed a full load wash with no problems. I haven't really done anything to cure the problem so I'm guessing that a little water must have leaked into the motor area of the pump and I displaced it during testing.

Was I just unlucky with this pump or is something else going on, like my earth leakage trip being over-sensitive? During testing I used a plug-in Belkin RCD which is supposed to trip at 30mA but that didn't catch the fault in time.