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My SGI3305GB (about 9 years old) has stopped cleaning properly. I have searched the forums but cannot find anything useful. I have pulled it out (it is built in) and I confess it has me stumped – I repair most things but I am confused. Left is my left as I look inside the dishwasher, front is the door.
It does everything it should except it leaves food on the dishes and coffee stains on the cups. Things on the upper tray are dirtier than those on the lower tray. I have seen the detergent tablet lying on the sloping base of the door – it wasn’t washed into the base of the machine.
It used to produce a “swishing” sound but now it does not so I think that the water is not being pumped hard enough. The electric motor has 240V at pin 1 and is spinning, but when I open the door and quickly peer inside, the upper spray arm is not spinning, the lower is only going slowly, and the water is only jetting about 3 or 4 inches above the lower rotor. All jets in both arms are clear and both spin freely.
I removed the upper basket and spray arm and ran it. When I opened the door I could see a jet of water from the back of the washer which would normally go to the upper spray arm. I seem to have volume but not pressure.
The spray arms are clear and rotate freely. The filters are clean and I have removed the cover plate above the small impeller just to the left of the microfilter and cleaned it out – the impeller spins OK (there was almost nothing to remove).
I have just replaced the microfilter (3″ dia, 3″ high) because the original one split so I may have some food blockage somewhere, but I cannot see where.
I can see the water levels changing in the labrynth (rear of left side) when it fills. The top left of the labrynth is badly discoloured but it does not appear to be blocked when I probe with a skewer. The water gets hot during the wash. Rinse works but no swishing sound and coffe and tea stains left in cups etc. It empties OK.
It used to bang when filling – I had assumed it was water hammer caused because the feed pipe had a long stub going upstairs which was blocked off at the time of the dishwasher install – but I don’t think it does now. Where is the inlet valve so I can check it?
The water level seems low – it barely covers the mesh filter and is not up to the salt filler. It empties OK and takes in (some but not enough?) water for the next wash. I poured in several jugs of water and raised the level to the salt cap, and tried washing, but it made no difference. I can see the red float on the left side rising and falling as the machine fills.
I have removed the sides but I still cannot see easily how to get at the pipework / motor etc underneath to check for no blockages as the white plastic tray at the bottom obscures everything.
Q1 How do I get access to everything underneath? Can I lay the dishwasher on its side or back, or will I then have problems that the labrynth gets confused? If I can lay it down, does that allow me to remove the white tray (or something else!) and get access?
My tentative diagnosis is that the water pressure from the pump is too low. It could be a blockage, or it could be that the motor is not rotating fast enough – I don’t know.
There is what looks like a cylindrical transparent container at the back left about 4 or 5 inches in diameter and 4 or 5 inches high which seems to be filled with what looks like coarse brown demarrarah sugar grains or dark sand. I have no idea what it is or whether what is inside should be there. I cannot get at it to check.
I will appreciate any help anyone could give me. I am an electrical engineer by training (it is powered off with the fuse removed when I am investigating) so I am used to doing most things round the house.
Or do I call someone in to look at it? Or is that just a waste because (s)he will merely say “It isn’t worth mending gov – 9 years old – buy a new one”. But the engineer in me screams that 99{e5d1b7155a01ef1f3b9c9968eaba33524ee81600d00d4be2b4d93ac2e58cec2d} of it is working fine!
Re: Bosch SGI3305GB – not cleaning – pumped water pressure l
You couldn’t find one of the numerous posts about Bosch machines underfilling? There’s one right HERE, not five posts below yours.
Penguin45.
Re: Bosch SGI3305GB – not cleaning – pumped water pressure l
Penguin45
Many thanks for your help, especially as the post to which you pointed me seems to have worked.
I realise that moderators like you give an enormous amount to the forum – your 19,000+ posts speaks for itself. I thought I did search very thoroughly before posting – I spent over 2 hours. My search arguement was bosch cleaning and while it picked up the post you pointed me to, its title lead me to ignore it -is “Bosch SGS4302 – not heating up and stuck on 1 minute”. Mine is heating up, and it does not stop after 1 minute, so I did not read it :-(. I did read at least 40 or 50 others though! Of course, someone more experienced than me would realise that the two symptoms probably shared a common cause.
Could it be retitled to include not cleaning in the subject?
Secondly, while you say “You couldn’t find one of the numerous posts about Bosch machines underfilling” I erroneously thought I had eliminated that by “I poured in several jugs of water and raised the level to the salt cap, and tried washing, but it made no difference.”
Also, I was working on the assumption that the red float (which I could see was operating the microswitch during fill) was the level control managing the water level. I now believe it is probably the overflow control – stop everything – we have too much water. Certainly, I have run a rinse and I am now running a wash, and in neither case did the red float rise off its floor. Its container has no water in it.
Anyhow, I removed the level control assembly and the pipe to the pump. Both contained small quantities of a very soft brown sludge – so little that I doubted cleaning it out would make any difference. However, I cleaned it all thoroughly and it seems to have fixed it!! Certainly, I am getting a much more vigorous sound from it like it used to do. I don’t have any dirty dishes to try it with as we have resorted to hand …
My observations are
1 During fill for both wash and rinse, the red float does not rise as the water level never gets high enough to cause it to rise. I assume the shallow circular diaphragm is the water level control – as the water rises it traps the air in it and operates the left / upper microswitch. I am now not getting any banging during fill. The fill water now courses through the assembly and into the pipe so fast only the bottom half of the pipe has water in it.
2 I was confused by the labyrinth. I now realise that the left two large bore tubes are the waste outlet “break the syphon” U with an air hole. I took the labyrinth off and cleaned the inlet water tube going to the float assembly – it did not matter that the Labyrinth was empty when I restarted the machine.
3 I needed to put some water in the machine to prime it to get it to go.
So, many thanks for your help! I will post again to confirm it is working when I have done a wash.
(As an aside, I guess that the head driving the water into the pump is only an inch or two, so any constriction or blockage in the pipe or assembly will have a big effect.)
Re: Bosch SGI3305GB – not cleaning – pumped water pressure l
Alas my optimism was unfounded.
The whole inlet assembly including labrynth, the water level control assembly, and the pipe from the water level control to the inlet of the pump are as clean as the proverbial whistle.
But I still don’t get enough pressure to get the spray arms spinning properly and I don’t get that “swishing” sound of the water hitting the sides and top of the washer. However, I think it is better that before I cleaned it. (I guess I thought the action was more vigorous after cleaning because I was running it without it being built in so it was noisier than normal.)
Does anyone have a suggestion for my next step?
Q1. Is it most likely to be the water pump or its impeller or a blockage in the pump? Should I remove the pump and clean them and see if the impeller blades have broken off?
Q2 Is it possibly the motor itself? I have 240V on pin 1 of the main motor, and the capacitor looks fine (no discolouration or leakage). Are there any tests I can run on the motor? I can borrow a rev counter – what speed shouldf it rotate at?
Q3 Is there anything more I can do to check for blockages somewhere?
Any help will be gratefully received and acknowledged.
Re: Bosch SGI3305GB – not cleaning – pumped water pressure l
ps…
I love the little bug in eastlmark’s sticky about cleaning dishwashers. It caught me out – I was thinking I would have disassemble my monitor before I cottoned on – wonderful!
Re: Bosch SGI3305GB – not cleaning – pumped water pressure l
The correct water level in the machine is about 1/3 – 1/2 way up the salt cap on the floor of the machine. Check that first. Assuming that that is correct, the circulation pump may be running slowly (unlikely). The circulation pump impellor may be damaged or partially detached (happens, not often) or there is a physical obstruction somewhere in the pipework.
If the water is running freely into the machine during the fill sequence, the red float should not be operating the flood protection microswitch at all. This turns on the drain pump and removes water from the machine.
Hope that makes sense,
Penguin45.
Re: Bosch SGI3305GB – not cleaning – pumped water pressure l
Thank you for your suggestions. It seems to be fixed (or it is certainly MUCH better).
The correct water level in the machine is about 1/3 – 1/2 way up the salt cap
The water level is about 1/2 way up the low (right) side of the salt cap.
I stripped the machine down (removed the front panel, undid the 6 external screws and the 4 internal ones, unscrewed the salt reservoir ring, unhooked the 2 door springs and lifted off the tub to gain access). I removed the pump and heater from the sump as a unit (I couldn’t separate them) and then removed the pump housing (rotate it after depressing the tab). Everything looked fine. The rotor is clean and undamaged and does not slip. I blew through the heater and it was clear.
I re-read the Basic Faultfinding Guide at http://www.ukwhitegoods.co.uk/modules.p … ge&pid=206 and wondered about the motor capacitor as a failing capacitor gives my symptoms (now that I have fixed the low water level) of not enough power from the motor.
I had a lightning strike recently which took out two PCs so I wondered if it could have damaged the capacitor. The motor is OK – the main winding is 50 Ohms, the phase-shift winding 75 Ohms.
I found a method of testing the capacitor on the web (I am a trained electrical engineer), and while it told me the capacitor was OK, the capacitor only had about 220-230V across it during the test, and I (later) measured 380V across the new capacitor when the motor was running.
I decided to invest £6 and I bought a new 5uF 440V flame resistant metal can motor start/run capacitor from RS Components.
It appears to be cleaning OK now. When re-seating the tub I forgot to re-seat the labyrinth and the level control pipes so I got a leak.
What do I think the problem was? Penguin45’s comment about the blocked level control assembly and pipe was definitely a factor because my red “overfill” float was lifting during fill which (I now know) is a sure sign of problems with filling. I remain amazed about how little sludge is needed in the fill loop to cause problems! I guess the sludge is from the water softener as the fill loop is quite separate from the recirculating loop used by the water when pumped during a wash.
Did the capacitor make it better still? I cannot be sure. I was going on how it sounds and I don’t think it sounds any different after the capacitor was changed. I think it used to “swish” more than it does but I cannot be sure. However, the £6 was well spent – taking the machine out and apart is easy, but time consuming.
… and Bosch machines are well engineered – everything is a push fit. I found the exploded diagrams on the Bosch web site very useful too.
So, many thanks for your assistance. I have posted details in the hope it will assist others reading it. I was initially quite daunted by the prospect of getting access to everything in the white plastic tray at the bottom of the machine but it turned out to be quite simple to lift off the tub (easier with a helper).
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