Zanussi ZDT41 thermostat replacement

[NeilCann]

Hi
I have a dishwasher that intermittantly wont heat the water and at the end of the cycle the items are cold and wet.
I suspect the thermostat and can order one relatively cheaply but before I do I would like to know if anybody knows where the thermostat is? And how difficult a job it is?

many thanks

[electrofix]

Re: Zanussi ZDT41 thermostat replacement

you may well be wrong as thermostats do not tend to be intermittent but there are always exceptions

poss causes
not enough water or safety pressure switch faulty ( check water level you can always add a bit and see what happens but not too much

broken wire from programmer to stat and or heater

programmer faulty

Dave

[NeilCann]

Re: Zanussi ZDT41 thermostat replacement

thanks Electrofix.

The only reason I assumed the thermostat as I have read elsewhere about them getting to temp on a cycle and either going closed/open circuit but getting stuck in that state and hence diswasher always assuming the water is at temp.

How do I check water level and add a bit?

I would have thought a broken wire or heater would not be intermittant either, I have had a look over the control pcb and all looks good no dry joints etc.

thanks

[electrofix]

Re: Zanussi ZDT41 thermostat replacement

wires go from the door and then go down below. with the door opening and closing it is possible for the wires to break

wait till the machine fills and starts washing and open the door and see how much water you have. if it looks a bit low add a pan full and see if it heats

thermostat is an NTC not a standard stat. it is a resistor that varies with temperature. It can go faulty and if it has it may have a resistance that makes the timer think its already up to temp

heaters can go open circuit when they get hot and close when they cool. not common but it does happen

Dave

[NeilCann]

Re: Zanussi ZDT41 thermostat replacement

thanks Dave

Sounds like it could be any number of things!!

I have tried opening the diswasher and seems to be as much water as expected.
If it was the thermostat is it any easy swap and where is it? cant find any info anywhere, I assume its will be under the machine and obviously in the water intake somewhere.
I use NTC`s in my job and these are all resetable but looking at them on parts suppier sites these are not, would like to measure the resistance when it goes wrong.
Seems to be if we switch the machine off at the wall for a while and try again the machine works fine for a while but always returns, very frustrating.

[electrofix]

Re: Zanussi ZDT41 thermostat replacement

have not checked service info yet as there are quite a lot of dishwashers with this model . I need your complete production number I then may be able to give you temp re resistance readings

Dave

[Seamy]

Re: Zanussi ZDT41 thermostat replacement

Dirty filter could cause this problem.
Sump clogged with gunge either causes intermittant heating errors.
Think this one has the thermister/NTC and turbridy sensor all in one unit.
We have found disabling the pulse washing on them gives a better wash result, then hopefully won’t gunge up again.

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