AEG Lavatherm 37700 (c. 1999) running hot

[IC WG]

Hello all

Our 20+ year old AEG vented dryer had a couple of sessions where it smelt like it was running very hot. The load wasn’t unusual and no obstruction was visible where the vent emerges outside.

I stripped it all down and gave the lower part of the casing which has 3-way vents a good clean and wash out. I’d previously given the vent box a vacuum out a couple of years ago. Overall there was remarkably little lint, dust, etc anywhere and none at all that I could see in the heater air duct, element, etc.

As far as I could tell there was a thermostat in the heater assembly and one in the channel leading from the door lint filter duct. I’d expect these to be fail-safe, so any problem would cause lack of heat rather than excess. Can they fail in a way that can cause overheating?

I’m wondering if I missed some components though as I thought there was a humidity sensor that helps set the “machine iron” to “extra dry” load condition LEDs on the front. Didn’t see it though – is there not one? Only other clue to any problem I can offer is that when putting a test load in that had got quite dry on the line outside I expected those LEDs to quickly jump to “hand iron”, etc – but they didn’t.

A couple of cautious drying sessions since seem to have been OK, but we’re trying to get back to not popping in to check on it every 5 minutes.

I have a multimeter and hot air gun that I can use to test hings if needed. Hints and tips welcomed.

[electrofix]

tried to look it up but the model is incomplete

are there any other numbers like a pnc number ?

Dave

[IC WG]

electrofix wrote:… like a pnc number ?

Thanks. PNC is 916 011 077 02.

I’m becoming more convinced it is the dryness sensor side of things that is problematic. I put a damp towel in last night and while there was no overheating odours it just kept running on initial / default programme countdown. No jump in timer when it realised it was a small load, and no lighting of the dampness / ironing LEDs even though towel was fully dried.

[electrofix]

ok that makes more sense

full model no is LTH37700

overheating problems are often the front stat

https://shop.electrolux.co.uk/laundry/tumble-dryers/thermostats/tumble-dryer-thermostat/p/8996471603812

the dryness is set by a conductivity sensor which consists of 2 brushes running on the drum to 2 electrodes that should be electrically isolated

check brushes and isolation

Dave

[IC WG]

Many thanks, that helped me find the problem.

There is just one brush which is on a hinged PP mount with a spring to pull it on to a special looking band of metal the drum, AEG part 647 071 680 on the diagrams I found, leading to this: https://www.mijnonderdelenhuis.nl/ae…470716805.html

The hinge was nearly fractured, but the remaining thread of plastic had allowed the brush to twist and drag on a different part of the drum – so on first inspection all looked well. I’ve now bodged the hinge with adhesive tape to see how things go for while. Initial test good – ran dryer empty and it turns off after a few seconds as it can now detect there is nothing to do.

If anyone on the forum can supply that part ex-UK feel free to let me know :).

[electrofix]

part no 8996470716805

AEG are showing as not available but gives a number to ring

https://shop.aeg.co.uk/search?q=:rel…nc:91601107702

the website you listed above lists no stock either

Dave

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