How do you utterly descale Smeg Dishwasher DF410SDXK?

15 Nov 2015
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London, UK
United Kingdom

The effectiveness of my dishwasher degraded over time. It's a DF410SDXK, purchased in 2011; though this is an ongoing issue.

Tablets don't quite dissolve (but I'm told that's normal).

The water is hot at the end of a programme, so I assume it's not a heater fault.

I took various measures to eliminate other problems (cleaned the filter; cleaned the spray arm; topped up salt; put the drain hose into a bucket at ground level in case it had trouble pumping up to the drain connector; run full programmes with appliance descaler tablets)

When I put jars in the top tray to collect water, they only collect 8mm of water over a full programme. (See pic. The programme was the "eco" setting. The glasses are the "right" way up - ie not the way I'd put them in if I was trying to clean them.) I infer the pump is not working fully. My understanding is that I should be able to fill them in 30s.

Oh, in terms of actually using the dishwasher: it just doesn't get anything clean. It hasn't even washed the gel soap off the soap tray.

I live in a very hard water area (East London), and other appliances that pump the mains water supply (eg a power shower) have been degraded to uselessness by limescale over a few years. So my theory is that the pump has been degraded by limescale.

Before calling out an engineer, would it be worth trying a heavier duty descaler? Possibly introduced into the water supply rather than the the dishwasher tub? (Not an option that involves opening up the device.)




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Dishwashers do not generally suffer from scale as they contain an ion exchange water softener inside, hence the need to put salt into it on a regular basis.

The hoses and spray arms can be easily blocked, usually when people put unsuitable items in such as paper and plastic film.
Thank you for answering.

Re: Hoses, do you mean internal hoses that would require opening up the dishwasher to clean?

I have let salt run low from time to time so it's not *impossible* I may have messed that up. But I've also run hot programmes with descaling tablets.

The spray arms have been cleaned, so that shouldn't be the problem. Am I right to think that those jars should indeed be filling with water?

There won't be film, but I do sometimes put jars & tins with paper on them there. (As you can see in the pic. Ow.) There's the filter to catch that. Though I know the two filters are not perfect because of the gunk that gets into the arms sometimes.
Why are you washing tins and jars in a dishwasher - if eco-recycling they only need rinsing out
All the gunk they contain and the paper wrappers are probably chocking your filter and pump
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Ecorecycling. So now we've established I've messed up, how do I fix it? Beyond cleaning the filter (which I have).
Going back to your original entry you state the tablets don't fully dissolve and that's "normal"
I'd consider it far from normal as the rinse operation is intended to remove all traces of the cleaning chemicals and if the tablet material still remains the rinse cannot possibly be effective.
Although the water is heating there may be a faulty temperature control
Time to spend some money getting a service check methinks.
For the original query - those jars should be full of water after a few seconds. As they are not, either the pump has failed or the arms/hoses inside the machine are blocked.

If the pump has failed it can be replaced, although it is a major cost item and may not be worthwhile.
If internal hoses etc. are blocked then the machine is probably unrepairable as the only way to clean or replace them is to dismantle most of the machine, after which it is guaranteed to leak.

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