Siemens Dishwasher Hydrosensor – no heat

[ian25]

Hi
I have a Siemens Hydrosensor Dishwasher SE25A090GB/17. The machine runs but we have noticed that it is not heating the water and the cycle now lasts for a very long time (e.g. over 5 hours) or doesn’t complete at all. There are no error codes displayed. I understand the washer is ‘self-learning’ in that it adjusts the cycle time based on the previous wash. Hence, now if you select a standard 50C wash it predicts it lasting 192 mins whereas usually it was more like an hour.

I am thinking that the heater unit has probably failed and needs replacing. Before further investigation and spending circa £100 for a replacement I just wanted to get some guidance on whether this is the likely cause. The dishwasher is over 10 years old and up until now has worked OK.
Thanks for your help.

[Martin]

Re: Siemens Dishwasher Hydrosensor – no heat

There are generally two reasons it is not heating. The most obvious being the heater unit (part no 00488856 – costs around £75 direct from Siemens) OR there is a dry joint of the heater relay terminals on the control unit PCB. The latter a simple fix with a soldering iron the former a major strip down to access.

[ian25]

Re: Siemens Dishwasher Hydrosensor – no heat

Thanks Martin. I’ve yet to pull the machine out and won’t have chance to do so for several days. But once I do I’ll take a look at the circuit board first. Thanks for the guidance.

[Trilobite]

Re: Siemens Dishwasher Hydrosensor – no heat

Perhaps the reason for non heating is that the transfer tube linking the water matrix to the sump is clogged with greasy gunk?

Clogs might cause water levels to be misread, leading to ‘no heat’.

According to Siemens’ exploded diagrams, this machine does indeed have the problematic transfer tube.

[ian25]

Re: Siemens Dishwasher Hydrosensor – no heat

Thanks Trilobite. I’ll check that out first. Much obliged.

[ian25]

Re: Siemens Dishwasher Hydrosensor – no heat

I have now had chance to look at the dishwasher. It did indeed turn out to be a dry joint on the circuit board (see photo – scorched joint towards bottom right). I have repaired that and it now seems to be working and heating up again fine.

Thanks for the pointer Martin as I wouldn’t have thought to look at the circuit board first. Saved me a lot of time and expensive from replacing a heater which wasn’t actually at fault!

Cheers!

[Author]

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