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My dishwasher has been repaired under warranty, and is now working. But I am worried that the model has a heater element design problem which means I will be in for frequent heater element repairs, in the future. I am hoping somebody out there who knows Bosch dishwashers will have an opinion.
The model is SMS69M12GB. It wasn’t cheap. It is 6 months old. The heater element went, and Bosch have replaced it under warranty. I was treated to a lecture on using salt, and shown the failed element to demonstrate, to the engineers satisfaction, that the problem was hard water scale.
I was surprised at the small scale of the element, it is a flat flexible 6mm-ish wide strip of some metal in a zig-zag pattern, bonded to a piece of steel about 25mm wide that forms a cylinder of about 80mm dia that goes around the pump outflow. The scale on the inside of that metal was, I would say, less than the thickness of 2 pieces of paper, probably about equivalent to 1 piece. I could see where the element had blown, though whether it was really due to scaling is hard to know.
Is this design of element a new thing? Our last Bosch dishwasher lasted 14 years, with one repair of a blown circuit board. I always thought heater elements were more along the lines of a kettle element, something with a lot more metal and a lot more robust. I can put as much salt in as Cheshire can produce, and it will still not stop some scaling, and if this design cannot tolerate 5-10 thou of scale, then it is going to blow very very often.
I can take out a maintenance/insurance policy with someone like D&G, but they will probably want, eventually, to replace like-for-like, and I don’t really want to have this problem for ever. Are all Bosch dishwashers using this element design? Did they always? Are there any other brands that use something a bit more scale-tolerant? I appreciate that with enough scaling, any heater element will fail eventually, but 6 months is ridiculously fast.
For those who may ask, the water company says that we have 18.4 Clarke hardness, so medium-hard – this requires an “H:04” Bosch setting, out of a scale from 0-7. We use the 3-in-1 tabs, that supposedly are enough for this hardness – the engineer says the problem is that after the cycle, water is circulated that therefore has no dishwasher tab salt in it, and that is why the element blew. We will revert to using bags and bags of salt, but I am not hopeful.
Opinions, anyone?
Re: Bosch heating element opinion please
The engineer was bang on about the frequent use of salt, absolutely vital, no question. Without it and your new heat pump will fail again very quickly indeed. The design of these pumps is fundamentally flawed in my opinion. They fail time and time again, even newly fitted ones. Quintessential rubbish if you ask me.
Sorry but that’s the truth. No other brand seems to have such an inherent weakness with their similar designed heat pumps (as far as I can tell at least)
🙁
Re: Bosch heating element opinion please
I’m a bit confused by that post. On one hand you state that the Bosch engineer was correct in his conclusion that not following the instruction manual led to the short life of the element, but then criticise the design for failure when instructions are not followed.
I have worked soft and hard water areas and there is a vast difference in the failure rate of water immersed elements, with poor maintenance or not following manufacturers instructions leading to the same result.
If you want to blame a design, then please point your finger at 3 in 1 tablets. 8)
Re: Bosch heating element opinion please
The instruction manual does not say that salt should not be provided in the form of tablets.
The instruction manual says that the amount of salt used should be determined by the water company’s figures for water hardness (which it was) not by simply setting the salt setting to maximum (which is what he did).
What evidence do you have that the salt in 3 in 1 tablets is less salty than salt in bags? Would a chemist agree with you?
Do you really believe that any heating element can be kept entirely clear of scale, and if not, what is a reasonable thickness for the element to tolerate? Is it 5 thou?
Presumably I am incredibly lucky then, that my previous dishwashers, washing machines and immersion heaters all tolerate our medium hard water.
And of course, presumably Bosch would never dream of saving themselves 50p on the cost of a component, thereby introduced planned obsolescence?
Anyway, it now has 3 in 1 and full hard water bagged salt – my guess is that it will react in the same way as your car does to winter roads – by corroding away. And good riddance to it, will be my view.Re: Bosch heating element opinion please
Chas_n wrote:The instruction manual does not say that salt should not be provided in the form of tablets.
The instruction manual says that the amount of salt used should be determined by the water company’s figures for water hardness (which it was) not by simply setting the salt setting to maximum (which is what he did).
What evidence do you have that the salt in 3 in 1 tablets is less salty than salt in bags? Would a chemist agree with you?
Do you really believe that any heating element can be kept entirely clear of scale, and if not, what is a reasonable thickness for the element to tolerate? Is it 5 thou?
Presumably I am incredibly lucky then, that my previous dishwashers, washing machines and immersion heaters all tolerate our medium hard water.
And of course, presumably Bosch would never dream of saving themselves 50p on the cost of a component, thereby introduced planned obsolescence?
Anyway, it now has 3 in 1 and full hard water bagged salt – my guess is that it will react in the same way as your car does to winter roads – by corroding away. And good riddance to it, will be my view.
“Planned obsolescence”
I tried to help, but I see where this is heading.I shall leave you and your tin foil hat alone.
Re: Bosch heating element opinion please
Chas_n wrote:The instruction manual does not say that salt should not be provided in the form of tablets.
The instruction manual says that the amount of salt used should be determined by the water company’s figures for water hardness (which it was) not by simply setting the salt setting to maximum (which is what he did).
What evidence do you have that the salt in 3 in 1 tablets is less salty than salt in bags? Would a chemist agree with you?
Do you really believe that any heating element can be kept entirely clear of scale, and if not, what is a reasonable thickness for the element to tolerate? Is it 5 thou?
Presumably I am incredibly lucky then, that my previous dishwashers, washing machines and immersion heaters all tolerate our medium hard water.
And of course, presumably Bosch would never dream of saving themselves 50p on the cost of a component, thereby introduced planned obsolescence?
Anyway, it now has 3 in 1 and full hard water bagged salt – my guess is that it will react in the same way as your car does to winter roads – by corroding away. And good riddance to it, will be my view.The element has probably not failed as such. All elements in situations like this have to have an internal thermal fuse to break the circuit if the temp rises above a set limit ( fire protection). Temp rise on the element can be due to limescale but also to lack of flow due to blocked filters. had one fail recently and the centre filter was well clogged up
and no i do not like the design. there is another manufacturer who has produced a mod kit to use a previous heater design which is far superior in my opinion
Dave
Re: Bosch heating element opinion please
Chas, I think you need to understand the function of a water softener and how, using ionised crystals, it extracts the harmful calcium and magnesium from the water. A 3 in 1 tablet does NOT contain salt nor does it have any water softening abilities. The manufacturers claim that it is a substitute for or instead of a water softener merely bluff, hogwash and spin.
Re: Bosch heating element opinion please
Martin wrote:A 3 in 1 tablet does NOT contain salt nor does it have any water softening abilities. The manufacturers claim that it is a substitute for or instead of a water softener merely bluff, hogwash and spin.
This is correct.
Other than in soft or very soft water areas salt is still required and pretty much, that’s it or any element could fail due to calcium build ups.
K.
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