Bosch Exxcel dishwasher constantly draining

[rodders1965]

I had problems with this UK model dishwasher not filling with enough water and the spray arms not spinning (both arms are clean and unblocked) which it was suggested could have been caused by two things, a faulty impeller jug downstream of the inlet valve, which measures the flow of water into the machine, or a blocked supply pipe from the water matrix into the sump. I removed the left hand side panel and cleaned this pipe and checked for any blockages. I also checked the drain pump impellor in the sump and it is fine. When I reattached the water sump supply hose, now when I start the machine on a cycle it wont start the cycle instead, it justs runs the drain pump continually, the red float drops down inside the chamber (it moves freely BTW) and the inlet water starts to flow into the matrix, then the float rises (some water also leaks out of the top of its chamber, though a tiny amount) and the inlet water supply is shut off. Then the drain pump kicks in again but stays like this indefinitely even though there is no water inside the machine base. If I manually push the float down it repeats the same thing again. There is not enough water in the base to activate the anti flood microswitch BTW.

The white disc shaped float made of polystyrene which sits in the base of the machine and actuates a vertical red plastic rod (Bosch's Aqua Stop system), is NOT sitting in a pool of water. How can the machine ever fill up if the float rises as soon as the inlet valve opens and the floats microswitch then shuts it off again and starts draining. I have an impeller jug on order anyway as the machine also used to pulse and bang when the water was being fed into it from the mains, which a faulty impeller jug was cited as being the cause. Wonder if it could also be causing these fill/drain loop issues I now have inherited.

Also why when water flows into the matrix and the float rises does it spill out over the top of the float chamber, surely this is because the inlet water is not getting through the matrix and water is therefore backing up? As I said the pipe that runs into the sump of the machine which is attached to the bottom of the float chamber, is unblocked so what else could be causing the water not to flow into the machine properly. There is a bit of crud and build up in the matrix but no obvious blockages. Any ideas?

 

[cjapeterborough]

Can you post model code and Fd number imprinted into inside door rim?

 

[rodders1965]

Can you post model code and Fd number imprinted into inside door rim?

Yes the model number is SGS45E02GB/?? I think, there is no number inside the door rim or on the door itself. I know there are two numbers at the end that this model might be, where i have shown two question marks which are 45, 52 or 56 but I dont know which. There is no serial number I can see anywhere on the machine in fact front back or sides!!

 

[cjapeterborough]

will try and help.........my 10p worth

Have you checked the circulation motor is working OK?

-easily checked by viewing the motor turning at high speed on the RHS of the machine with the panel off.

If this isnt working/jammed or leaking then this will cause a backup
and activate the flood -although you say there is no water in the base.

Have you checked the drain from the sump?
-sometimes this can be blocked.
This can be cleared by disconnecting from the matrix,removing the return flap valve
near the torx screw in the sump and blowing through from the matrix side.

You may indeed have a faulty impellor-the valve banging is down to pressure changes between your mains
and your machine and is very common sometimes folk fit pressure restrictors to the feedpipe to deaden the shock.
I doubt this has much to do with your overfilling problem though...

 

[rodders1965]

Thanks for the tips CJ but I have fixed it!!!! Took off the entire matrix assembly and the water feed to the sump hose (AGAIN!). I thought I had cleaned out the latter on my last attempt, but there was still some crud in there. To get the other end of the this pipe off I had to remove the panel under the door and the metal plate underneath. Quite fiddly. The matrix itself was also hard to clean but I poured a degreasing agent into the tubes and boiling water then left it upside down for an hour, shifted 99% off the gunge in there. I also disassembled the float chamber assembly and microswitch and found a blockage in the small vertical water channel under the float itself. Cleaned the whole thing until it sparkled, then reassembled the float mechanism and actuating arm and switch. I then dried out the base and checked the anti flood mechanism was working properly. Reasssembled the matrix and connected up all the water pipes once more and switched on the machine again, having reconnected the external water supply. Fingers crossed.

It ran fine and looking at the way the water is sent to the sump via the matrix, I can see how easily it could become blocked owing to the tortuous route the water has to go through! Let the machine run a whole cycle and checked for any leaks. It was only after two hours that I sat in front of the machine for the real acid test. Would it stay stuck on 1min display.............then....zero......hoorah I actually fixed it myself and saved over £100 in repairs if I had called soemone out. Dishes are now clean and dry. Chuffed to bits I have sorted it out!!

 

[cjapeterborough]

JOB WELL DONE!!

Congrats....