Washing Machine Fault Diagnosis

[KaneH]

Evening,

Had the washing machine trip the RCD the other day and am trying to troubleshoot the cause as I’d rather fix than replace if possible given it’s less than 4 years old.

Originally would power up without a fault but when you start a cycle the door mechanism would lock and it would trip the breaker. I recently wired up a new supply to the shed so thought I’d cocked something up in the process. Checked the supply, no apparent issues, then plugged the machine in to another socket (upstairs via an extension lead) which is off the other RCD on the consumer unit and tripped that too. So pretty sure it’s the machine at fault.

As it was tripping when the cycle went to start I disconnected the interlock switch and powered the machine back up. Power would come on without tripping the board so I thought it must be the interlock switch. However I tried to hit the start button and it tripped the breaker again. Now what I’m unsure of is with the interlock switch disconnected would this cause the RCD to trip or is this likely pointing at something else? I do hear the switch click when it is connected suggesting that it is functioning?

From reading online I understand that when the cycle starts there’s a number of items energised (interlock, motor, heater etc) so thought if the switch is activating it could be something else. Going to pick up a multimeter tomorrow and check resistance across each of the components but not sure what values I should be looking for, any hints?

As you’d guess I’m a novice at this sort of game so any advice is welcomed.

Cheers

Kane

 

[waddycall]

I’d be tempted to disconnect the heater element and see what that does.

 

[rtbcomp]

I had one tripping the RCD it turned out that a coin had worn through the heater and shorted it to earth.

I wouldn't expect the heater to come on unless there was water in the machine, but it could give a neutral-earth fault without switching it on (or live-earth if the switch is in the neutral side)

Disconnect both heater connections.

 

[WorkshopChris]

Going to pick up a multimeter tomorrow and check resistance across each of the components but not sure what values I should be looking for, any hints?

If its operating a RCD your first point of call should be to-measure any resistance to earth.

 

[brightspark]

If its operating a RCD your first point of call should be to-measure any resistance to earth.

preferably with a megger

 

[KaneH]

No megger tester unfortunately. I’ll check with a multimeter later this afternoon and see what I find.

 

[rtbcomp]

Another possible culprit is the mains supressor, they're connected to live, neutral and earth so an internal fault to earth will trip the RCD

 

[Rig Pig]

Check the pump is dry, a leak round there will short it out.

 

[voipio]

Is it located near a kitchen sink? Had an RCD issue with water getting under the draining board and dripping onto the washing machine and finding its way into the electrics.

 

[KaneH]

Had the lid off it yesterday and didn’t see any sign of water inside. No water on the floor around the machine either so don’t think a leak is the cause.

Would the interlock switch activate if it were the cause of the problem? Or would the short happen as soon as it energised so you wouldn’t hear it click?

 

[Nell#2]

I'd look at the biggest pull of current heater would be the highest?
any spade connections loose?

 

[rtbcomp]

...
Would the interlock switch activate if it were the cause of the problem? Or would the short happen as soon as it energised so you wouldn’t hear it click?

Impossible to say, the fault isn't necessarily a full short circuit. As mentioned a few times the heater is the prime suspect. #2, #3, #11

 

[Gritineye]

Does you machine have a self test mode you can run to see if any error codes show up?

https://www.how-to-repair.com/help/...ol-awod-awd-series-repair-faults-test-errors/

 

[earthman]

Am I right in saying that older washing machines, ones that have a hot and cold feed inlet, don't have a built in heater element?

Those were the days, I were surprised that the last new washing machine I got only had one inlet hose. Lol

 

[GrahamGKD]

Am I right in saying that older washing machines, ones that have a hot and cold feed inlet, don't have a built in heater element?

Those were the days, I were surprised that the last new washing machine I got only had one inlet hose. Lol

I think they still had a heater element - or at least the ones we had back then did.

 

[angellonewolf]

not that i knoiw loads about washing mechines but untill the door lock is actvated there will not be much to take out the rcd as untill the door lock has latched no power should be sent to the pump or moter or filling valves

i belive the first to get power after the door lock has engaged is the pump to see if there is any water in the mechine it runs for a few seconds and then on to the next in line (not a washine mechine enginer ) but think im right in this

 

[KaneH]

Looks like it is the heater that’s the problem. Run a cycle with it disconnected and no issues thankfully.

Thanks for the suggestions everyone!

 

[rtbcomp]

Am I right in saying that older washing machines, ones that have a hot and cold feed inlet, don't have a built in heater element?

...

They all had heaters because you can't guarantee that the hot water will be hot enough. I have the hot & cold inlets connected to give a cold fill as I don't always have the hot water switched on.

 

[rtbcomp]

When you replace the heater look out for a clip which is fixed to the outer drum and engages with the nose of the heater element to stop it catching the rotating drum.

 

[Seadog]

Looks like it is the heater that’s the problem

Should've used Calgon