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My Zanussi ZDF26011WA is several years old, and has stopped heating during the wash. It is still pumping water OK.
So far I have checked the following:
The heater resistance measures 24 ohms
The temp/turbidity sensor measures approx 5k ohms at room temperater, falling to approx 1k ohms when placed in just boiled water
I have removed the pressure switch and cleaned out the feed pipe from the sump to make sure it is not blocked
When I run the Auto wash cycle, I can hear the heater relay engaging, and measure 240V on the heater at the start of the wash cycle, and I can feel a little heat developing inside the dishwasher, but the supply to the heater stops after the initial stage of the wash (approx. 10 minutes) and never resumes. I tried running the 30 minute 60 degree cycle, and did not measure a voltage supply to the heater at any point.Can anyone suggest what the problem might be, or anything else I should be checking, please?
It sounds like my sensor values are in the right ball park then? I’m a bit puzzled why I get power to the heater for the start of the Auto cycle, but nothing at all on the short 60 deg cycle, if the temp sensor is faulty.
Just an update, after more detailed investigation, to see if anyone had further suggestions.
I have run a few tests of the 65 degree short wash, and can confirm that the dishwasher is heating, but only to approximately 36 degrees. At the start of the cycle, I can measure 12v on the heater relay, 240V across the heater, and the water heats up, but the heating only appears to kick in for a few minutes, until the temperature reaches the upper 30s, then stops. When I reported no power on the heater in my earlier post, I suspect I just didn’t have the multimeter leads correctly inserted, and missed the short period of initial heating.
So the heating circuit seems to be functional, but just is not operating for long enough to get things heated up properly. I replaced the temperature/turbidity sensor, but that has not made any difference to the operation of the dishwasher.
Assuming the new temperature sensor is working correctly, and the heating circuit is working, I guess there could be a fault in the controller itself, i.e. the controller board is incorrectly interpreting the temperature sensor and assuming that the water has reached the correct temperature? That seems like quite an unlikely error, however, as everything else on the controller board seems to be working fine (programme cycles, water fill, water drain, etc).
one of the problems here is if the machine senses a problem it switches off the heater and continues the programme. what we have to do is try to figure what.
have you checked the heater for earth faults as these can sometines upset electronics but can often be not enough to blow an earth leakage tripDave
I only have a multimeter, so unfortunately I can’t test the heater for earth faults. I might take a chance and try replacing the heating element.
Thanks again for the advice.you can use the meter on the highest scale with the heater disconnected and see what reading you get
swoppinp parts in the hope of a cure is a risky process
dave
No sign of connectivity to earth using my multimeter, but I think things would be blowing anyway if there was
you can get leakages to earth that upset elecronics but not enough to blow anything
out of simple ideas now
could be be a board faultDave
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