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I’m hoping someone can offer a little bit of advice. I have a Siemens Siwatherm C7 condensing tumble dryer (E-No. WT72000GB/02) that no longer gets hot. Well, if I have it on the “low” temp setting it doesn’t. If I have it on the normal temp then there is a faint warmth and the metal panel on the back gets slightly warm. I have taken the back off and measured the odd thing:
Element 1: 130 ohms
Element 2: 40 ohms
Thermostat with red thing in the middle: 0 ohms
Some sort of thermistor (I think) at the top of the heater: 20 kilo-ohms at room temp, reducing to 5 kohm when heated with a hair dryer.I assume the difference in heater element resistances is due to them being designed to generate different amounts of heat – one of them I guess is not used when on “low” temp setting.
It seems to me that all this is OK and is unlikely to be source of the problem. Is there anything else I can take a look at before either getting an engineer in or buying a new one (it must be 10 years old and other components will probably be nearing the end of their design-life).
Thanks for any help with this.
John
have you tried pressing the ‘red’ thing?
it should not be open circuit
unusual, both elements i would have thought should measure the same. the difference between low and high heat is whether it uses one element or 2
Re: Siemens Tumble dryer not heating
The red thing doesn’t appear to move so I assumed it hadn’t tripped (if that is what it is supposed to do) but maybe it is a single-shot type. It was not clear to me whether it should normally be closed (zero resistance) which is what it is now, or open.
The elements are actually slightly different physically – one of them is about twice the diameter of the other – if you think of the coil as a tube of coins, one is 1p pieces, the other 5p, if that makes any sense 😆
For something that should be really simple, these things are complicated – the devil is definitely in the detail.
Re: Siemens Tumble dryer not heating
Thanks helo_75, but it really won’t push in! Anyway, I don’t think that is the problem – it is not open circuit as far as I can tell – it measures zero ohms. I wish it had been that though – I was hoping for something simple and obvious but just my luck to get a tricky one :rolls: !
Re: Siemens Tumble dryer not heating
Finally had time to take some more bits off this blasted thing and got at another thermistor at the front of the machine. This one reads 12.5kohm at room temp and drops when heated with the hair dryer. If all the thermistors and the thermal cut-out are OK, and the elements appear to be unbroken, what is left to go wrong? Could the pcb be faulty and if so is there anyway of checking before I consign this to the scrap heap?
Any more suggestions (polite ones please) gratefully received.
John
Re: Siemens Tumble dryer not heating
Oh well, it’s done sterling service over the years – all those baby clothes that it shrunk, not to mention the waistline of my trousers – odd that.
I might just check for any dry joints before I give up altogether – a new pcb is just too expensive to be worth replacing at this stage.
Thanks for your help.
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