The following might assist you.
After the partial failure of our dishwasher (DW) (Tricity Bendix BK280), where the dishwater was not draining, I decided to try and understand its operation and attempt a repair, if say, a blockage, or simple component repair/replacement could be performed, before accepting that I really need to fork out £500 for a new machine.
I contacted Electrolux (Tricity Bendix) who refused to offer to supply me with servicing information, “due to safety reasons”. So ironically I proceeded to take apart the DW without any guidance at all!
I made the following observations:-
The timer controller, is mechanical, using a motorised cam operating 4 changeover switches. I carefully took apart/ reassembled the timer controller, finding no obvious problems, i.e. burnt out contacts. Using a Digital Multimeter, all contact resistances seemed OK.
Whilst giving the inside of the dishwasher a thorough clean, including taking apart and washing each internal washing compartment part, I could not find any obvious blockages. I did not attempt to clean any other pipework nor devices outside the washer compartment, other than the waste pump, and the waste pipe was clear. I applied power to the waste pump, which worked OK.
Now that I discovered that the waste pump seemed OK, I then tried to perform further washes.
I observed carefully the DW operation under its programmes 2 “Normal No Prewash” and 3 “Quick Wash”, by the following methods:-
1. Listening to the machine: waste pump operation (waste pump hum and drainage gurgling), water inlet valve operation (flowing filling water), wash operation (wash pump hum and water sprinkling from the turning arms).
2. Watching the timer control knob turn and listened to its cam motor. In particular I noted that the control knob would turn at 1 minute intervals, but would stop for about 18 minutes when the heater element was turned on. I assume it restarts when, presumably a thermostat operated at the required temperature of 65C.
3. Fitting a mains power meter to monitor electrical current. I noted: 1A for main wash pump, 0.22A Drain Pump, 12A Heater, ~0.01A cam motor, ~0.03A Fill Valve.
During these observations I then noticed that the water inlet valve would not operate after the hot dishwater waste was drained. I manually interrupted the DW and filled it with cold water by hand (err... jug). I then allowed the DW to continue its operation, but during the next cold rinse cycle, the water inlet valve operated correctly. This seemed to indicate that the water inlet valve was “sticking” under high temperatures.
So I was able to understand batter the DW basic operation, recording also that programme 2 used 1.75Kwh of electricity (1 hot wash 2 cold rinses and 1 hot rinse), programme 3 used 0.91Kwh of electricity (1 hot wash 2 cold rinses).
I was planning to further disassemble the DW, but my wife was desperate to get the growing mountain of dirty cutlery/crockery shifted. So then whilst getting ready to interrupt the half working DW for a 3rd time (lucky?), the water inlet valve operated correctly!
Could it be I started using a new detergent (Finish Powerball)?
The most likely problem I had was that we had poorly maintained our DW, and never performed the recommended “use of Finish Dishwasher Cleaner every 3 months, or run a wash programme without dishes using detergent” as stated in the User Manual.
greg-the-grey, January 2009
