Dishwasher Help Forum

[Mechaniac]

Hiya, recently was given one of these (Oh thanks Mum!) and having read a few posts on here realise that they are not very highly thought of. Ok, its the timer sticking problem again. I noticed that if I fed hot water into the machine, skipping its own self filling point, that the timer would then progress as normal, well, until the next drain/fill cycle. With that I traced the fault to some kind of thermal switch. Replaced switch and test run the machine on the bench, so to speak. And... of course it worked until I got the thing re-installed back in the kitchen. Of course. Ok, the long and short of it is that the new switch is now bust again, so I take it that the machine is overheating, tripping what seems to be this one-shot switch? Any help would be appreciated. Richard.

[aqualectric]

Is the cut out you refer to a small black unit with 2 tags and a brass threaded fitting? If so, there are usually 2 fitted to most of these oriental machines. One at the back in the middle of the tub (screws up into a threaded bush under the tub) and one behind the right hand side panel (fitted in the same way). You need to change both as one affects the other.

Power off before any inspection.

Steve.

[Mechaniac]

Ok, I shall have a look into that. So what does the one behind the side panel do? Many thanks, Richard

[Penguin45]

Model number would help.......

Penguin45,
Moderator.

[Mechaniac]

Oh sorry... yeah its a Proline pdw080 or something like that. Little slimline effort... Cheers.

[Mechaniac]

Ok, I can find no electrical Gizmos behind either panel.. The heater element itself shows signs of quite deep blueness in places- is this normal, or evidence of overheating. I seem to recall going through a spares list, and I think this 'safety switch' was available, but also a pair of 'control' thermostats?? Could the failiure of these cause the machine to overheat, tripping this safety switch? Whereabouts are these, can they be tested? Cheers, Richard.

[Mechaniac]

Ah... so is one of these thermostats designed to trip at 75 degrees? and should it fail then the second non-resetting thermostat cuts the power at 90 or thereabouts, stopping the machine from boiling? Is that it? So, i should be able to test the 75 degree by doing a continuety test by dropping it it in a pan of water.. I should find it trips well before the water boils, and resets again as it cools back down? Does that make sense?

[Mechaniac]

Ah, looking further, this seems to be of an obsolete design. There are a pair of thermostats held against the bottom of the machine, via a plastic holder complete with springs, with some sort of heat conducting paste as a medium. I take it that one of these thermostats tells the timer that operating temprature has been achieved, and so advance, the other one should cut the power to the heater at a temprature a little above the "operating temprature". I shall do my best to test these.... any further advice anybody? Other than skip it.... I must admit.. I like a challenge.... Thanks all. Richard.

[Penguin45]

The two in the clip are the operating or 'cycling' thermostats. You're looking for a brass and plastic doofer screwed to the floor of the tub. It looks like THIS.

Penguin45.

[Mechaniac]

Yes, Ive got that one... thats the one I replaced, only for it to blow again. However, mine doesnt have a plastic red peg sticking out of it...Some sort of re-set?. The other two, in the clip are marked at 50 degrees, i think, and 58 degrees. When warmed, the 50 degree unit closed and was found to have continuety. The higher value item,58, could be heard to 'click' but no continuety. The design of these switches allowed me to carefully dissasemble it, where I found the contacts were pitted. Cleaned them up and re-assembled this switch, which then tested ok. So.... Am I to take it that the lower 50 degree switch lets the machine know "Hey, Im at operating temprature now, lets get on with washing" wheras the higher value switch instructs the machine that it is getting too hot, so cut the power to the heater? If this higher switch fails, then the machine will keep heating until the safety thermostat cuts the power, permanently.....? Does that seem to be right?

[Mechaniac]

Ok, machine has been tested over and over and happily works fine now. Many thanks to all those who have offered help and advice. Richard.