Dishwasher MRO

Ok, so now the dishwasher is back in action how do I keep it that way? Well the manual for the machine had some advice

􀊋 Check spray arm for grease and limescale deposits.
If you find such deposits:
􀊋 Fill detergent dispenser with detergent. Start the appliance without utensils in the programme with the highest rinsing temperature.
Clean the appliance with detergents/appliance cleaners which are particularly suitable for use with dishwashers.
􀊋 To extend the life of your appliance, clean the appliance regularly with a special dishwasher detergent.
􀊋 To ensure that the door seal always remains clean and hygienic, regularly clean it with a damp cloth and a little washing-up liquid.
Regularly wipe the front of the appliance and fascia with a damp cloth; water and a little washing up liquid are adequate. Do not use sponges with a rough surface or abrasive detergents, as these could scratch the surfaces.
Special salt and rinse aid
􀊋 Check the refill indicators and, if required, refill salt and/or rinse aid.

.... blah, blah, blah, yawn.

More succinct instructions were to be found on the Which website, where a nice man in a suit shows us how to clean an immaculate dishwasher. I kid you not, look

Britain's Best-dressed Dishwasher Repairman

The list of to-dos is straightforward and the provision of repeat periods means the information is easy to put into a recurrent job.

1. Clean the dishwasher filter - Weekly
2. Wipe the dishwasher door seals clean - Weekly
3. Top up with dishwasher salt and rinse aid - Monthly/when indicated
4. Remove and clean the dishwasher spray arms - Six-monthly
5. Run the dishwasher empty and hot - Six-monthly

JOB DONE.

Break-time over

Ah well, back to it.

Currently we're having a white/brown goods situation, so let's start with the dishwasher, which presented itself like this,

mmm, lovely.

After emptying the machine by hand and checking that the pump wasn't blocked and was running freely, running a rinse cycle replicated the problem so it wasn't a flyer. Taking the machine out of its' alcove showed that the waste path out of the washing chamber didn't seem too bad.

Water handling matrix of a Neff S51E50 dishwasher

The waste flow is the corrugated pipe coming in from the pump on the right-hand side and going up into the matrix, the flow then loops over and exits out via the white pipe to the back of the machine. Visually it looked OK. There does appear to be some residue in part of the matrix but A) I'm not sure this is causing the problem and B) there is no way in to clear it out as the matrix appears to be a sealed unit. Running a rinse cycle into a bucket worked fine.

The next port of call was the path from the waste pipe into the sink waste water plumbing. No need to see that part of the process, it was pretty foul (it'd gie yer the boke).

40mm waste water pipework

40mm trap seal (L - old/R - new)

After cleaning out many years of grot and replacing a dodgy 40mm trap seal that had been stretched and was leaking slightly it went back together no problem.

So all good, replaced the dishwasher waste pipe and ran another rinse cycle and hey presto! No change.

Disconnected and repeated the rinse cycle running it into a bucket: no problem. Is the pump not efficient enough? Ran another rinse cycle with the waste pipe elevated above the height it would usually connect at; no problem. Hmm..., reconnected it back to the waste piping and now it's back to working normally.

What was the problem? Basically I'm not sure. Current and final thoughts are

• Waste water was not draining, but pump was working. Therefore, probably, not due to a blockage in the waste path.
• So either the programmer or an associated detector wasn't working properly.
• No reason why it should just start working again if it was the programmer.
• A flaky sensor is a possibility but that is likely to reappear as a fault.
• Or the check valve on the waste outflow (if there is one) was allowing waste to siphon back into the machine.
• But on the first occasion the water was very gunky, indicating that it hadn't been through the rinse cycle at the end of the programme, so siphoning seems unlikely.
• Or the pump wasn't working properly.
• But if this was it, it must have been a blockage rather than a mechanical issue with the pump.
• Or repeated rinses may have removed an obstruction or crud and this might have brought it back to life.

Or in short, I have no idea but don't care as long as it keeps working.

Time spent : Day and a half, off and on.
Cost : £0.59 for replacement washer.