Bosch SMS3042GB/03 – no water coming in

[dwp]

Have a Bosch SMS3042GB/03 dishwasher which suddenly stopped taking in water, just made a ticking/buzzing noise. I read various suggestions in this forum, such as checking for sludge in the hose from sump to matrix – none found. Also checked microswitches on the water matrix and on the ‘leak detector’ holder with the white float block at the bottom – both ok. Checked both the mains water inlet hose and the waste outlet hose – no blockages found.

Took water inlet valve + solenoid out to test and it seemed faulty (just sat and whined a bit) so ordered a new one. Cost £48 but when I fitted it the water still doesn’t come in. It sort of ticks continuously during the water inlet phase, then just goes quiet. I put a meter on the solenoid terminal and it reads 240v.

Can anyone suggest what to try next please ? Having spent this much I don’t want to give up without a fight.

[Penguin45]

Re: Bosch SMS3042GB/03 – no water coming in

Supply tap isn’t one of those self-cutting jobbies is it? Notorious for clogging up. The buzzing noise should be the valve opening, so I’d check for actual flow from the fill hose next.

Penguin45.

[dwp]

Re: Bosch SMS3042GB/03 – no water coming in

Thanks for the response. The supply tap is one of the inline type with a small plastic blue handle which turns through 90 degrees, turning a hollow ball inside. Is that the sort you mean ? Anyway I connected the hose to it, took the other end off the inlet valve, aimed it into a bowl and turned the tap on. There was no lack of flow !

So it looks like water is getting to the inlet valve ok, it’s just not getting any further. Any more ideas for anything I should try ?

[cockney steve]

Re: Bosch SMS3042GB/03 – no water coming in

If the solenoid is powering, I’d expect to hear a pronounced “click” followed by a mains-frequency hum ,as long as the valve is held open.

Have you checked the wiring circuit TO and FROM the valve…..you could well have a loose or corroded connection there somewhere.

REMEMBER TO UNPLUG FIRST !!!! WATER AND ELECTRICITY DO NOT MIX WITH INQUISITIVE FINGERS.

[dwp]

Re: Bosch SMS3042GB/03 – no water coming in

I don’t hear a click from the valve, the ticking noise I get may be the control knob creeping round. As I said, the meter shows 240v on one of the solenoid terminals, but I didn’t measure the other one, so don’t know what drop there might be. I’ll check that next, I think it goes to a terminal on the pump.

I could also test the valve with it disconnected – what sort of resistance should I expect from the solenoid coil ? Does the machine simply apply 240v AC across the solenoid when it calls for water inlet, or is there anything else apart from microswitches in the chain ?

[cockney steve]

Re: Bosch SMS3042GB/03 – no water coming in

I’d suggest you try your local library for a “haynes” repair manual…IIRC, this covers washers ,vacs etc. -but only in a general operating principles sense.

Ultimately, yes, your solenoid will have one side “earthy” (more correctly,it’ll be Neutral and the other will have 230 on it…..the switching from the controller, pressure-switch etc. will be series when it has power on it BUT…it’s not necessarily the LINE that’s switched 😯 This is why it’s important you understand the fundamentals!

Unplug machine, disconnect solenoid coil and do a simple continuity check on it,-if your machine has more than one solenoid, just compare the coil resistances.
I’d *guess* about 1.5K as a rough figure.

I don’t think it’s wise to direct you further, other than to suggest using the Forum’s “find an engineer” link.

[dwp]

Re: Bosch SMS3042GB/03 – no water coming in

Thanks for the advice. I disconnected the inlet valve solenoid and the coil resistance measured 4.2K (another solenoid nearby was 2.7K). I did some more checking with power connected – when the controller is turned to the water inlet position, one terminal of the solenoid (the one with the brown wire) is switched to 240v but the other terminal (with blue wire, in series with the float microswitches) is not switched to neutral. So this terminal is also at 240v and no current flows through the solenoid coil.

I took the door front panel off and traced the wires up to the door switch and controller. The door switch is working ok and the neutral wire to the solenoid from the controller (via the anti-flood device in the base and the microswitch on the matrix) is intact. But the contoller isn’t supplying neutral on this wire. All the rest of the wiring appears in good condition too and all the connections seem sound.

I need to do a bit more checking to see if I can find the problem, unless anyone has any suggestions ? I’m hoping it’s not a faulty controller because they list at £83 and that spells the end for this dishwasher !

[Penguin45]

Re: Bosch SMS3042GB/03 – no water coming in

Timer fault for sure, I’m sorry.

Future readers be advised that UKWhitegoods will not condone, or assist with live appliance testing. In almost all circumstances, faults can be diagnosed by continuity testing only.

Please don’t do it.

Penguin45,
Moderator.

[cockney steve]

Re: Bosch SMS3042GB/03 – no water coming in

Well, DWP, unless you “normally” work with electricity , you’ve had a lucky escape from this year’s Darwin Awards 😉

As Penguin says, It’s extremely dodgy unless you’re really familiar with the techniques and safety-procedures.

you could always look on “fleabay” or “loot” and find one of the same model, with a good timer..

I must confess to having stripped and repaired a mechanical timer…it wasn’t a long-term fix, due to the non-existence of contact-blades,cam-followers etc.
If you just want to see how one works, that’s different,

BUT DO IT WHEN IT’S DISCONNECTED! live safe and long.

[iadom]

Re: Bosch SMS3042GB/03 – no water coming in

cockney steve wrote:If the solenoid is powering, I’d expect to hear a pronounced “click” followed by a mains-frequency hum ,as long as the valve is held open.

TBH, you do not hear any kind of a click when solenoids used in domestic appliances are energised under normal circumstances.

Jim.

[dwp]

Re: Bosch SMS3042GB/03 – no water coming in

Thanks guys, both for the advice and for the concern for my safety. Actually, the only live testing I carried out was just to check the solenoid voltages, everything else was done with the mains cable disconnected from the wall. I’m no electrician but I’ve been working with electricity in some form for about 45 years, I’m currently (!) in IT technical support, which frequently involves running kit with its innards hanging out. I also completely rewired my house in the days before the H+S industry decreed we are all too stupid to be trusted not to kill ourselves, and no-one found that shocking.

So I think I’m more likely to qualify for a Darwin for the stupidity of wasting my life, spending longer trying to fix this dishwasher than it would take me to earn enough for a new one. Still, that’s curiosity I suppose, and a hatred of throwing away anything with some life left in it. It’s amazing how much satisfaction there is in spending three hours repairing an object that cost a quid and was definitely not meant to be repaired !

If the general opinion is that it’s a controller fault then I guess that’s curtains, but yes I probably will take it to pieces – that old curiosity again ! A dishwasher is one of the things I’ve never stripped down before, so it will fill a hole in my RAM. And it would be very satisfying to actually see the cause of the problem.

[dwp]

Re: Bosch SMS3042GB/03 – no water coming in

Thought I’d just update this call in case it helps anybody else. It wasn’t a faulty inlet valve, or a timer fault, but I did solve the problem and the dishwasher has been running perfectly for a little while now.

I started taking it to pieces because I was interested in how the timer controls everything, and ended up drawing out a complete circuit diagram. Once I’d done that I realised there was no continuity in the neutral wire from the mains input at the bottom to the switch panel at the top of the door.

This puzzled me because the flat ribbon wiring from top to bottom looked in good nick, even where it bends at the hinges when the door opens. It has heavy flat sleeving on at this point so I peeled back part of this and found the neutral wire (fairly heavy gauge, coloured mauve/white) on the extreme left-hand edge had sheared clean through, even though there was no external sign of any damage. The other conductors in the ribbon were all ok, so it must be the neutral one on the edge that gets the most stress as the door opens.

I soldered a bit of replacement wire in place, insulated it well and added a bit of padding. Result : fully functioning dishwasher !

So, just a tip for anybody else with a similar problem – check all the wiring, even if it looks in perfect condition, you never know what’s lurking inside. It could be that this Bosch design is prone to fracture of this particular wire after a number of years.

[cockney steve]

Re: Bosch SMS3042GB/03 – no water coming in

😆 It’s great when people DO take the trouble to post the outcome.

I’m glad you managed to find your fault….the fault is common in the car-trade where wiring-looms go into doors from the pillar (though they’re far superior now!.)…….Also , back in the ’60’s the “Ex” had a Bendix washer-dryer,which had a hefty loom between casing and door,-of course, it was ordinary wiring and the cores succumbed to work-hardening, being flexed back and forth every time the door moved . Consequently,as you found, they could part, leaving the insulation intact.

if you were “lucky” the broken ends would arc a bit and the burnt plastic would show where the fault was.
It’s particularly noticeable with the Japanese electronics/electricals, that the strands are extremely fine on their flexible conductors,rendering them far “softer” and less prone to fatigue.
I did the same “fix” as you…it outlived the rest of the machine 😛

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