Taking it to pieces

[thurgarton]

I have a Hotpoint Aquarius DWF31 dishwasher which, I believe has suffered a heater element failure. I have stripped the machine as far as I can – top and sides off but it is impossible to access the heater without removing the base. This. however, offers no clue as to it’s removal. I have unlocked the metal bracket below he door which appears to locate the base but I can find no means of removing (or pivoting) the base to gain access. There is a hole on the front of the base which is marked with a double headed horizontal arrow and arrows pointing down (left of hole) and up (right of hole). Hole runs right through base and has holes in it through which you can shine a torch. Hole appears to have a u shaped insert running its full length but I have no idea whether this is meant to rotate in the hole to allow the base to hinge downward, nor do I have any tool that would let me do this. Can anyone advise please as I don’t want to spend £150 on a replacement if I can’t fit it!!

[iadom]

This is a Bosch based machine and the heating element is part of the heater flow chamber. This involves a massive strip down and even experienced engineers baulk at doing these. The inner tub does have to be completely removed. Basically, top off, sides off, door off, complete inner tub off. Getting it all back together is the really tricky part.

Are you certain the element has failed, it’s far more common for the control module to suffer burnt out solder joints to cause this fault.
Have you tested the element across it’s terminals for continuity and resistance?
The up and down arrows are for raising and lowering the rear feet, may not even be used on a free standing machine, usually for built in appliances. The base could well be used across a wide range of machines.

[thurgarton]

Thanks for your prompt and helpful response and explanation regarding the base. I haven’t tested the element as I don’t think that it is possible to reach the heater element terminals from the side but will check. Presume you are referring to the PCB in the door re solder joints. I must admit that, having found that everything appeared to work with no fault codes but the wash was awful as the water hadn’t heated, I presumed that it was an issue with the heater element. I will post again once I have made further checks.

[iadom]

Element terminals are accessible from the right hand (looking from front) side.

[thurgarton]

Thanks for the advice. Looks as though you were right as heater unit has continuity with a resistance of 23.4 ohms (with all the connections still in place). I’m about to check the PCB.

[iadom]

Most of this model range was subjected to safety recall many years ago for pcb faults. Not sure how would stand given the advanced age of this appliance?

[thurgarton]

Thanks for the info. My machine has no serial numbers (I’ve checked all the locations) and as I was given it I have no evidence of sale so I doubt that Bosch would be interested!
Have still to check the PCB – went a bit too far with dismantling and now have the door off its hinges rather than the PCB off the door! Will need to fix that before checking PCB. I presume that the resistance is ok as, from other threads i was expecting a slightly higher reading.

[electrofix]

the model numbers on this machine are on a sticky label at the top centre of the door. look on the stainless steel but look to one side. the label is see through and not easy to see until you know its there

https://www.hotpointservice.co.uk/safety-notice-dishwasher

it still asks you to proceed on your model number saying its at risk

Dave

[iadom]

As a rough guide the service manual I have for this model is dated 2001. Your machine will be around 18 to 20 years old. 😉
Heater reading is fine.
Some of these had the ID label stuck directly onto the top edge of the inner tub, just under the top. Most of them also had the very difficult to see, etched serial plate along the top, inner edge of the door. Again you need to get it at just the right angle to see it clearly.

[thurgarton]

You are right – but the label is extremely faded. Managed to get the door back on – I see what you mean by a complete dismantling is a nightmare! So I am now able to look at the PCB. It appears that it has a hinged cover which is very hard to release, also I am not sure which solder joints I am looking for. Any suggestions. The last white goods I stripped was a Hoover Keymatic in the 70’s so you will appreciate that I am a bit rusty at doing this kind of thing.

[iadom]

The assembly complete with cover will slide out from the metal backplate if you locate the correct securing lugs. Then you should be able to open the two halves of the plastic holder. This plastic does become rather brittle with age. If it is the pcb then the damage is usually obvious. As it is a known fire risk resoldering the joints is not advisable.

[thurgarton]

Removed PCB. Nothing obvious re dry joints and those connections that I can check for continuity seem ok. Looks like I might need a new PCB!

[iadom]

On older machines the wiring harness can break near the hinge where it bends. These models are not as prone to this type of failure as others though. Also not sure if the pcb is still available. It was made obsolete more than 10 years ago but then came back in stock. Not cheap especially for such an old machine even if you can still get one.

[iadom]

Did you remove the pcb completely from the holder and check for signs of burning on the back of the pcb?

[thurgarton]

e spares are quoting £258 !!! Really not worth it. I am just going to rebuild the dishwasher and cross my fingers (or perhaps try a dry joint remedy by oven baking the boards to try and restore any dry joints). Many thanks for your help

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