More white goods failure - dishwasher now.

[julianf]

So, just recently, with the forum help, I've managed to avoid buying a new tumble dryer (stuck relays) and fixed my compressor (various faults) and now the dish washer has died!

It's an old Bosch one. It must have a PCB somwhere but I also wouldn't be surprised if it was just relays.

Here's a photo of it, it's a really basic one -

The issue is that it's not filling with enough water, so the pump has nothing to pump really.

It seems to fill with a bit, as the feed pipe "jerks" as the solenoid shuts off, but not enough.

I can tell this by setting the sprinkler arm to a known position, and, when I reopen the door, whilst it's dripping, it will be in the same position, and I can't hear it spinning from outside.

If I manually Chuck some water inside, it's all back to whooshing about again.

Until it tries to drain and refill for the next part of the cycle.


We have had the unit for years, and I replaced the solenoid about 6 months ago, as the old one was not shutting off perfectly, so would dribble over time, causing leakage.

I mention this as the solenoid is then quite new, but has been working fine for about half a year, maybe longer.

My question at this stage is how these machines know when to stop filling?

I'm assuming they're not just timed, and they have a sensor?

I guess what I don't get is that the external feed pipe shudders as the solenoid closes, so there is some flow, but obviously just not enough (for whatever reason) is getting into the machine.

I need to work out why.

Thank you once again!

 

[wacky7791]

take the left panel off and there will be a plastic thing that fills with water, in it there will be a little cog thing that spins when it fills with water (if I remember correctly)and a
sensor, it lets the machine know it is filling and determines how much. when it gets stuck it'll do what yours is doing. main power PCB I believe is behind the RH panel near the lower rear corner (its been a few years since I worked on these) but it won't be that.

often just pulling it out of the hole and tipping it back 45 degrees will free off the fill level sensor.

 

[wacky7791]

actually could be a float switch rather than a spinning gear on that one, similar to a toilet cistern float but much smaller. been a while since I've worked on them but tipping it back can free them off.

 

[julianf]

Thank you. What you say confirms my suspicion -

The sump for the diaphragm switch was full of slime. I'm not sure if that would stop it working, but I've just cleaned out most of it and am waiting to see what happens now.

Thanks again.

 

[frank horton]

suprising how much muck u get with mains water......

 

[zx9]

suprising how much muck u get with mains water......

The water is warmed when the washer is in use, it is open to the air allowing slime and gunk to grow over the years.

 

[julianf]

I think I've stuffed it up more, and / or made no difference -

I took out the diaphragm unit, and it seemed to be pretty much inactive. Ie a blockage or somthing. A lot of sustained pressure was needed to change the diaphragm state.

I took it apart and there is a sort of pinhole insert that was the restriction, I suspect it's a sort of denounce design, but it was really very restrictive indeed.

I thought I'd take the insert out to check the other side and, ping, it flew off to join all the 10mm sockets in another dimension.

Anyway, I thought I'd reassemble without the pinhole but and at least see what happened, but, I think its possibly the same as before -

I didnt think the unit was filling before, and this was tested by manually putting in water, but what appeared to be happening before I gave up and went to bed was -

Solenoid opens
Water comes in
Level float rises (not the diaphragm, the other one)
Diaphragm switches (I've tested the micro and it works)
Water continues
Level float activates
Pump out starts and empties the machine again. But it seems to go forever as it can't seem to grub up the last bit of water to deactivate the float.

Or maybe I've misunderstood it and it's then trying to run on dry again. It was getting late so maybe I was getting confused.

Either way not working and now I've lost the pinhole bit on the diaphragm (diaphragm and micro are working but, as I say, I suspect it was a denounce thing)

Don't know what to do now.

 

[badabec]

Try giving espares a call. I have found them very helpful

https://www.espares.co.uk/

 

[addjunkie]

While I understand fixing things, and the satifaction gained from such things. For a little over 200 quid, you could remove the hassel. If you value your time to earn also a new one may work out cheaper

Are there any filters on the inlet and out let restricting your flows

 

[julianf]

While I understand fixing things, and the satifaction gained from such things. For a little over 200 quid, you could remove the hassel. If you value your time to earn also a new one may work out cheaper

Which was very much my thoughts in the small hours of this morning.

It's just frustrating, as most of these things fail from such a small cheap parts, but it's just working out which one. The tumble dryer was fixed with a £3 relay (and a whole load of time!)

Another significant factor -

This machine is fully mechanical. If I replace it I'll probably end up with an electronic box, which will be less fixable than this (as yet unfixable) one!

So, most of me agrees with you. It's just uncomfortable consigning somthing to landfill for the sake of one part, just because I'm too dumb to work out what part.

 

[Pigeon_Droppings2]

Last time mine broke it "just" needed a very good clean. Amazing how much rubbish accumulates inside the machine. On mine the little channels were getting blocked because we have hard water. I soaked in citric acid for a day which shifted it ...

 

[Cobbler]

We had a Bosch dishwasher very similar to that, it packed up & the service guy said there was a problem with a dry joint on the circuit board, it was a common fault & he found it in seconds. It ran for another couple of years & went wrong again. A clued up friend had a look at the board & found that where the dry joint was, it had overheated the resister on the other side & had failed. From what I recall, that showed up as a filling problem.

 

[RonA]

While I understand fixing things, and the satifaction gained from such things. For a little over 200 quid, you could remove the hassel. If you value your time to earn also a new one may work out cheaper

Are there any filters on the inlet and out let restricting your flows

As Groucho Marx once said “Its not the principal its the money”
RonA

 

[julianf]

I think it may be sorted. As in I've even put the sides back on... (so it probably isn't!)

The dirty bit is the float chamber. The float worked fine, but that little bleed off pipe to the lower section was restricted.

It seems that the machine fills. I'm not so sure what the diaphragm level sensor is, but it appears to do some sort of dance between filling and then the float going up, it pumping out for a second or so, filling for half a second, pumping for a quarter, and then going onward to the next stage.

I feel it probably shouldn't be like this, but, with the leak off from the float chamber restricted, the pump out cycles were too long. And the machine ended with no water at the start of the setup.

Now that the leak off is sorted, it does about 3 quick cycles of fill, pump, fill and then starts up on the next part of the cycle.

It seems an odd way of doing things, but it seems to be sorted now. I guess I'll know at the end of the program.

Thanks to all, once again.

 

[addjunkie]

Good news, now go and quickly spend the 200 quid on tools, before you need to buy a new dishwasher next time it stops

 

[Will!]

Congratulations! I normally have a window of 2 days to diagnose, buy parts, and fit; before a new washing machine / dishwasher / car turns up. 24h turnaround is spectacular indeed.

 

[slim_boy_fat]

I thought I'd take the insert out to check the other side and, ping, it flew off to join all the 10mm sockets in another dimension.

But.....but....those pingfeckits must have been performing a function of some sort [apart from catching the unwary 'repairer'], what if they all come back for revenge on account of your have furloughed them?