Bosch dishwasher not heating in some modes

[mjt111]

Firstly, Happy New Year to you all,

I’ve got a problem with my Bosch SMV63M00GB/01 integrated dishwasher. It started playing up yesterday after a lots of use over Christmas!

It’s not cleaning properly. In the Auto and Eco modes I don’t think it’s heating the water and it’s just doing a cold wash. It’s not coming up with any fault codes. Strangely, on the intensive 70 deg C mode it works fine though. Lots of steam comes out when I open the door mid cycle.

So I assume the heating element must be fine and a thermostat or temperature sensor is faulty. I’ve looked on the Bosch spares diagrams for the machine and I can’t see any temperature sensors. There’s an Aquasensor (00611323) shown in the top side of the sump but I don’t know what that does.

Any advice would be much appreciated.

Thanks

[Martin]

Re: Bosch dishwasher not heating in some modes

Dry joint on main circuit board the most likely reason.

[mjt111]

Re: Bosch dishwasher not heating in some modes

Hi Martin,

Thanks very much for your reply.

I took out the main board last night and had a close look at the back of it. I couldn’t see any signs of arcing at any joint or any damaged tracks. I did a resistance check between the component pins on the wide power tracks but didn’t get any strange readings. Some joints looked a little ‘powdered’ so I de-soldered and re-soldered about half a dozen. I re-assembled and tested it again and there’s no change. It only heats the water on the hottest 70 deg cycle. The others are cold.

Is there anything else you can suggest?

Thanks
Matthew

[Martin]

Re: Bosch dishwasher not heating in some modes

Not a symptom I can recall. So I would have to check the heat pump unit resistance across the NTC terminals (5,6&7) and that “aqua” (Turbidity) sensor. Heat pumps are a major issue on this series of Bosch machines unfortunately, especially if you haven’t been using salt in a hard water environment. 🙁

[mjt111]

Re: Bosch dishwasher not heating in some modes

Martin, before I gave up and called in a service engineer I thought I’d try a new Aquasensor. It was only £13.85 with postage and it was dead easy to fit. I’m pleased to say it cured my problem. The machine now heats the water in all cycles again. 😀

Thanks very much for your help, it’s much appreciated.

Cheers
Matthew

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