Bosch Exxcel dishwasher - fills/drain repeatedly

[Mikexx7]

My 2 yr old Bosch Exxcel dishwasher fills then immediately drains (healthy output) for a few seconds then fills then drains and the cycle continues until switched off. This is accompanied by water hammer but that might not be due to the machine.
There is no blockage through to the sump and drain pump and also the rubber non-return valve near the drain pump is clear of debris.
The timer remains at the start time for each program.
There is no water in the base and so the anti-flood is not activated.

I have so far changed the inlet water valve and the controller.

Should the heater flow switch get activated as the water comes in or only when the main pump operates?

What is the circular unit on the base of the heater unit?

Does anyone have the complete electical sequence?

Any suggestions would be much appreciated
Thanks
Mike

 

[unclebuck001]

whats your model no mate

 

[Mikexx7]

Model no. is SGS45E02GB

Due to pressure from the domestic management I had to call in Bosch. The fault was in the impellor jug (flow sensor) that is used to measure the fill level, presumably calculated by the controller. I mistakingly thought the float was doing that but the float is just for overfill and anti-flood.
An expensive mistake this time but I'm ready for when the controller packs up!
Mike

 

[unclebuck001]

yep

 

[middlecp]

Hi have the same issue with my BOSCH Dishwasher, Model SGS53C02GB...

Is the Impeller Jug Sensor a typical fault that causes this issue...?

How do you get to this part...?

 

[LynxPilot]

I have the same problem with the exact model number you describe. Is this something I can fix myself? The funny thing is that I this problem occurred precisely 1 day after the 2 year warranty expired!!

 

[middlecp]

Hi,

After changing the control unit the problem stayed..!!!!!

What I did in the end was to put as much boiling water into the machine as I could get and left it for an hour....

Then put it onto a cycle and hey presto...!

Hope this works for you but the impeller jug I never found so no idea where it is..
Chris

 

[LynxPilot]

Thanks middle cp, I'll give it a go. I did manage to find the impellor jug but it was working fine, mind you my fingers are in shreds after getting it out!

 

[middlecp]

Hi how did you get to the 'Impeller Jug' and what does it do...?

Thanks

Chris

 

[assuhors]

The impellor jug is located between the inlet valve at the back of the machine and the water matrix on the left hand side of the machine.It has a hose in and out on it.It has an impellor in it which rotates at a speed dependant on the water supply,each revolution is monitored by the PCB so the correct amount of water is taken in.

 

[bigp1953]

Had same problem with impeller jug on Exxcel ModelSGS46E02GB after 21/2 years passed it would fill sump and empty but nothing in between with the check water light coming on paid £70 for a local engineer fix with part available at £15.99

 

[MikeHoug]

Bosch Exxcel dishwasher fills then immediately drains (healthy output) for a few seconds then fills then drains and the cycle continues until switched off. This is accompanied by water hammering noise whilst the machine switches continuously between filling and draining.
There is no blockage through to the sump and drain pump and also the rubber non-return valve near the drain pump is clear of debris.
The timer remains at the start time for each program.
No wash cycle will run.
There is no water in the base and so the anti-flood is not activated.

My machine is acting exactly as described above. Having read through many posts, I am of the opinion that the impellor jug (flow sensor) is possibly the cause so I'll replace it and report back as to whether it fixes it or not.

Thanks.

Dec 2009 - Ok, I replaced the impellor jug (cost £20 inc delivery from the web) and sure enough it cured the problem. Not too difficult to replace, just a little fiddly.

 

[MSG2]

I had the same problem as MikeHug in his first email.
My dishwasher is a SGS43T62GB/35

I changed the impeller jug by a new one bought over the internet and now the dishwasher seems to work perfectly.

I think the resistence between the two poles should be 0 ohms when no water is going through and the impeller is not rotating. And the resistence should increase when the impeller is rotating. So you may check if the impeller jug works OK if you measure the resistence with a multimeter on the last spots of a connector strip on the right back corner of the dishwasher behind the right panel (I think the green cable of the impeller jug connects to the penultimate blue cable and the yellow one is connected either the last blue cable or antepenultimate blue cable). My theory is that when water goes into the diswasher the resistance between the last two spots in the connector strip closest to the back right corner should increase. I haven't studyed this theory throughly once I saw the dishwasher was working again, so I am not 100% sure it is flawless.

 

[TS]

I removed the impeller jug from the dishwasher, and removed the small PCB from the impeller jug using a pair of pliers. On the PCb you'll find a 'reed switch' which basically is a switch that responds to magnetic fields. When a magnet is nearby, the switch closes, when the magnet goes, the switch opens up again. THis can be measured with a multimeter in the "Ohm"-position.

Unfortunately the switch is still ok, but the dishwasher is still malfunctioning (same error as mentioned above)

> Update: it now seems that the contact between the small PCB and the edge-connector was not optimal. Cleaning with contact-cleaner and bending the plastic snap-on to hold the contact seems to have solved the problem.

 

[jonnyz]

This post helped me solve my repeated fill drain problem with my Bosch however i got lucky and managed to fix the impeller jug by tapping it and rubbing a magnet over it to free up the magnetic reed switch. I didn't have to replace it (so far). Defo worth a try.