Bosch SGS69A02 dishwasher bottom arm not spraying

[sean5302]

I know I’ve had this machine 9 years but it cost me £600 and has been very good until now.
It’s a Logixx Auto Option dishwasher model SGS69A02.
I live in a soft water area and have checked the spraybars, which are like new. No blockages.
I vaguely remember that this machine has a valve somewhere that sends cleaning water first to the top spray bar and then to the bottom.
I’m only getting water to the top bar so something has failed.
Does anyone know what sort of a job it is to strip down and repair?
Any instructions etc, please?

[Martin]

Re: Bosch SGS69A02 dishwasher bottom arm not spraying

The ‘instantaneous water heater’ will need replacing to cure that fault.

[sean5302]

Re: Bosch SGS69A02 dishwasher bottom arm not spraying

Thanks.
I’ve been looking around the internet and it seems heater part 488856 is the one I’ll need.
Bosch Appliances UK want £158 for this.
I’ve seen similar ones on ebay, secondhand for around £25.
I’ve just bought one so I’ll post my success or failure here.
It looks like a major stripdown to fit these.

[sean5302]

Re: Bosch SGS69A02 dishwasher bottom arm not spraying

I stripped the dishwasher down and tested the instantaneous water heater.
When I put 240V across the little motor terminals, it works fine, rotating at 1 rpm.
The plastic wheel rotates and I can see the orifice holes open and close.
It seems the root cause is there is no power getting to this motor in normal operation.
Is there a control board problem that may be common to these?

[sean5302]

Re: Bosch SGS69A02 dishwasher bottom arm not spraying

Fixed it.
I took the Copreci motor from my £25 ebay part and fitted it in place of the existing motor.
Fortunately, both motors and their spindles are identical.
I can’t say that about the rest of the instantaneous heater block. Lying ebay seller sold me the wrong part.
Anyway, I can now see that my old motor turns fine when there’s no real load on it. As soon as it comes up against a load ie trying to close a port that’s open and feeding water through, it fails to turn.
Thanks for the help.

[clivejameson]

Re: Bosch SGS69A02 dishwasher bottom arm not spraying

Unlikely that’s its failing under load, there’s actually very little load on it as it’s a ‘hit and miss’ type valve.

IIRC there are position switches within the gearbox, it’s conceivable that if they are not working correctly then the pcb won’t power the valve. Either that or you’ve had a solid object (piece of glass?) get wedged on there and it’s chewed a few teeth off somewhere on the drive.

[Martin]

Re: Bosch SGS69A02 dishwasher bottom arm not spraying

The stuff you can get on eBay and the resourcefulness of some DIYers never ceases to amaze. It is true to say that in this case that the gearbox and cam are put under load by the sheer pressure of water. The tiny motor cannot cope under the strain. Likewise the nylon gears wear equally and the whole thing dies as does the water shaft seal. There are only two realistic long term options, either to replace the complete (new) heater unit or scrap the machine.

[Author]

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