Zanussi ZDT6255 not completing cycles, no fault codes!

[labman]

Hello,

My Zanussi ZDT6255 dishwasher has developed a fault. When on a standard wash cycle it gets about 10minutes into it then starts having problems. I can hear plenty of water sloshing around as normal and pumps working but it gets so far then starts cutting in and out. It seems to be trying to fill with more water as I can hear the cold supply pipe rushing, it does this 3 or 4 times in short succestion then just cuts out. When I open the door all the lights are out and its completely dead. To reset it I have to unplug it and switch it back on again.
If it helps it has got to the point of releasing the detergent as the tablet is part disolved at the bottom.
I’ve also noticed the water is cold, so either the heater element is not heating or its not got to that part of the cycle.
If I run the cycle again, I can hear it drain the old water then start the process and the same thing happens.

If I run a rinse and hold cycle it drains the old water, refills, sloshes around for a good while then stops and is sat with a buzzing/humming sound. This time when I open the door the rinse and hold cycle light is on, closing the door again results in the buzzing noise and nothing else happens. This time to reset it I can just press and hold the rest buttons as normal.
Again, no audible warnings ar fault codes are given.

I’ve cleaned the filters and there doesn’t appear to be any blockages immediately visable. Wash arms are clear and spin ok, salt/rinse aid etc all topped up.

Any ideas whats up?

Thanks

[Penguin45]

Re: Zanussi ZDT6255 not completing cycles, no fault codes!

Almost certainly the pcb at fault. These suffer from burnt-out/dry joints on the heater circuit and the transformer for the power supply has been known to break down.

If you can wield a soldering iron, it’s worth having a look.

Power off first, mind.

Penguin45.

[labman]

Cheers for the pointers.
I’ve got the PCB out and no sign of any dry joints, certainly no charing or signs of over heating round the heater circuit, I re-soldered all the components anyway, not the SMD ones minds.

I noticed the white block connector with the 2 orange wires is connected and assuming this goes to the heater element I measure the resistance. Its open circuit. Sounds like the element has gone, if this is where the orange wires go to. Would you agree?

[helo_75]

its a good shot, and if the pcb is ok, then it has to be the heater

[labman]

PCB seems to be fine because I’ve put it back and still no change. Seems odd that the heater would cause problems during a rinse cycle though. The water never got hot during rinse cycles previously.

[helo_75]

well, it should have done

they all do

[Penguin45]

Re: Zanussi ZDT6255 not completing cycles, no fault codes!

A “standard” programme is normally:

Cold pre-wash.
Hot wash.
Cold Rinse.
Hot rinse and dry.

Meter heater – you’re looking for an ohms reading in the 20’s.

Penguin45.

[labman]

Well I think I’ve tested it and its open circuit, trouble is its right at the back and a bugger to get to. Any ideas how to get it out, can the main wash compartment be removed easily?
Or do I need to break my arm in several places to get to it?

[labman]

Managed to get the heater out, its fine. 25ohms.

Just run a rinse and hold cycle and just left it buzzing, it did this for about a minute or two then finished and did the end of cycle beeps, so maybe its done this all the time and I’ve just never noticed.

Tried a 30min quick wahs and after a few minutes the soap dispenser flap solenoid started going beserk, I noticed it was doing this the last time we used when it actually worked. With all the covers off I can also see that when it hits trouble the 30min light switched ona dn off as the pumps and motors are switching in and out.

So, would a dodgey soap dospenser solenoid cause thiese problems or is more likely (As I suspect) that the main PCB is knackered?

[labman]

Now thats interesting, as I was writing the last post, the thing sprung back into life.
It starts and seems normal but then cuts out, starts again,….cuts out, starts again,… cuts out, starts again,….. cuts out,… then just gives up and all the lights go out!

[Author]

Posts