Zanussi ZDT21006FA beeping four times – pressure sensor error

[enthusiasticamateur]

We have a Zanussi ZDT21006FA (911539205-03) integrated dishwasher which recently refused to start a cycle and beeped four times (repeatedly). The manual says that this means there is a problem with the water pressure sensor. I took the pressure sensor out and soaked it in white vinegar, then replaced it and the machine started to work again for a few days, doing about five full cycles, before reverting to the same problem (four beeps). So I ordered a new pressure sensor for £16 on ebay and replaced the old one. The machine did one full cycle successfully but then when I tried to start it the next time it beeped four times. I am confused now as it has a brand new pressure sensor so how can there be an error with it already. I am also confused as to why the problem is intermittent.

Any ideas as to how to fix this would be great! I don’t mind tinkering with the inside if it avoids having to junk an otherwise good machine and spend large sums of money on a new one. Thanks in advance for any help.

[electrofix]

have you checked the pressure chamber for blockages ?

Dave

[enthusiasticamateur]

Hi Dave, many thanks for your reply. I haven’t checked the pressure chamber, only because I’m not familiar with dishwashers so didn’t know there was such a thing as a pressure chamber! Do you have a picture of what it looks like so I can locate it? I’ve had a look at the Zanussi spare parts catalogue for this machine (here: https://shop.zanussi.co.uk/search?text=91153920503) and I can’t see anything labelled as a pressure chamber so I’m not sure what I’m looking for!

Thanks.

[electrofix]

the pressure switch works with air not water so there is a chamber like an upturned cup that traps water and turns it into air pressure for the switch to operate. these can get gunked up and stop the switch operating

its actually moulded into the sump. i get a cable tie and being flexible you can work it around and see what comes out. i do it with a small amount of water in so it washes the rubbish out

Dave

[enthusiasticamateur]

Amazing, thank you so much. Is it possible/sensible to do this while the dishwasher is upright and in situ, or should I be taking the sump out to clean it in the sink?

[electrofix]

put a pint of water or so to fill the sump. use warm water as its nicer to work with

get a cable tie and curl it to push it up into the chamber, then just jiggle and furkle around. anything in there should end up in suspension in the water so you will be able to see if anything is in there

Dave

[enthusiasticamateur]

Dave, I can’t thank you enough, that worked a treat. It was full of grease. I ended up removing the water pressure sensor and poking the zip-tie through from the sensor side into the inside bit of the sump as I didn’t want to accidentally push the grease from the other side into the sensor. It’s successfully running a cycle now and hopefully it continues for many years to come!

[yulita11]

I’ve registered specifically to say thank you for this post. My dishwasher is Indesit. Same symptoms: intermittent red flashing lights and complete stop. You saved me buying the pressure sensor. I opened mine up, tried blowing into the pipe connected to pressure sensor and it was almost impossible, like playing a trombone 😀
Tried my best cleaning it up where the air was bubbling out, got a few bits and pieces out. Made the air flow free. It’s now on third cycle, going strong and happy.
Thank you!

To add to this, my dishwasher was about 8 years old, no wonder it accumulated some unpleasant residue down around the waste.

[matrixresonator]

Very common issue with Electrolux made machines, steam cleaner is good too for cleaning those chambers out if you have one handy.

[Author]

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