ZDE47200W Tumble dryer not heating

[azrael]

Hi all,

I have an eleven year old Zanussi ZDE47200W (91609336601) Tumble Dryer which has been having problems recently.

For quite a while it had problems starting to spin (but once it started it was ok), until it stopped completely. Opening it up the drive belt was a saggy mess, replaced it. It went back to taking trouble to start, but working when it did start. I replaced the capacitor, it spins like a boss!

Before it stopped spinning completely, the heat was fine. Since I began my repairs, it no longer heats. I removed the heating element and gave it a good visual inspection, it seemed fine (no breaks in the coils) but I gambled on buying a replacement. After fitting the replacement, still no heat.

I’m not really sure what to check next and hope someone is able to provide further advice.

Thanks in advance

Manual: https://www.manualslib.com/manual/509522/Zanussi-Zde47200w.html

[electrofix]

have you tried wet clothes in it as some machines wont heat unless they sense dampness

or try a timed programme, some of those dont need to use the sensors

Dave

[azrael]

Thanks for the suggestion Dave!

While doing repairs of the spinning I guess most testing has been with an empty drum (to see if it spins) or more recently a few items to see if there’s heat. But somewhere in there we did try a load that had been waiting a few days – which in my mind needed drying, but could reasonably be considered only slightly damp.

I’ve just put a new wet load in and let it run for 10 minutes. I was hopeful! But sadly, no heat 🙁

(a very small part of me is relieved as if this was the issue I’d have to kick myself quite vigorously!)

I’ve read about thermostats possibly being an issue but haven’t yet been able to identify wher ein my machine they might be. The cable that connects the heating element tracks back to the front control panel – could there be an electrical issue in that board? Would I have any hope of being able to identify something like that?

[electrofix]

checked the wiring and the only stats are on the element

early machines had one over the door but not on yours

get a multi meter and check the stats on the element assembly

and check heater for continuity, it may be new but even new parts can be faulty

Dave

[azrael]

Thanks Dave,

Knowing there are no additional thermostats does seem to make it a bit simpler for me. Very wise advice that even new parts can be faulty!

I don’t have a multimeter, but will tomorrow! I’ve seen a youtube video where someone shows how to test the heating element with a multimeter, so I’ll try that.

many thanks!

[electrofix]

the element has 3 wires and you should get readings across any 2

Dave

[azrael]

Thanks Dave,

Multimeter arrives today and in low resistance mode I am getting readings across all combinations of 1,2,3 in the diagram you provided – both on my old heating element and my new one!

I’m interested in testing the cable inside my dryer that the heating element attaches to – I presume that’s the next thing to check?

With my dryer off and unplugged, I assume there won’t be a circuit through these cables so the fact that there’s no reading on this shouldn’t surprise me.

Is there a way to test this cable without a live current in it? It should go without saying, but I’ll say it anyway, I have no desire to electrocute myself!! 😀

[electrofix]

you can disconnect from timer end and do a continuity test on each wire

Dave

[azrael]

Thanks Dave,

I’ve re-tested the end of the heat element, then disconnected the far end where this plugs into the control board and tested there.

I’m not sure I’ve got my 1,2,3 in the same order as in the diagram, but the readings I’m getting in ohms (set to low on the multi meter) are ith the different pairs:

1+2 = 83 ohms
2+3 = 119 ohms
1+3 = 36 ohms

I get the exact same readings from the heat element cable and from the other end of the long cable when it is plugged into the heat element cable.

Are these readings right?

Checking the thermostats on the heating element, there are 4 ‘ends’ and checking every combination of pairs each has resistance though it varies (which presumably it should to accommodate different cotton/synthetic termperatures?).

Now I have sight of the control board, I can see the identifier on it pcb 712529-02. I have labelled it and as I cannot upload here I have linked at https://imgur.com/a/NGOy4T8

So #4 is where the power goes in (must works as the dryer turns on, spins, etc.). The heating element plugs in to #5.

I’ve done a visual inspection and can’t see anything weird (burn marks or the like) and painstakingly tested each resistor for some resitance, and they all have some.

Any further ideas of what I can check eithe ron the control board or potentially elsewhere?

[azrael]

Hi Dave,

Thinking I’m not really skilled enough to do any more detailed messing around with the circuit board, I put it back in and reassembled the tumble dryer while waiting for further advice. I turned it on with random “maybe it magically works now” hope – the heating element went red within seconds. It hasn’t been glowing at all in the past (almost) week!!

I swear I’ve jiggled the cables to try and make sure they’re all well seated in the past. But maybe something was loose and dissassembling and reassembling has re-seated something.

I’ve dragged the tumble dryer back to where it lives, tested it with wet clothes – its working!

I wouldn’t have done (whatever I did today) without the confidence gained through the support you’ve provided. I’m truly grateful, thank you!

[Author]

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