My mother in law has a Bosch KDN30X00GB/01 Upright fridge freezer (freezer at top). The evaporator had frozen up completely and was encroaching on the fan blades making it very noisy. There was no air circulation as everything was blocked with ice. After manually defrosting with a hot air gun, I found the defrost heater & assumed that it had failed but testing it confirms that it is functional. It's rated at 240V/155W and I measured 377 Ohms resistance. The defrosted water drain was clear, the airways haven't been impeded and the appliance doors have never been left open. Without a circuit diagram, it is difficult to know exactly how the unit is controlled. There is a sensor measuring the temperature over the coil. I assume that this will just start & stop the compressor or is it involved somehow in the control of the defrost heater? I haven't measured the resistance of the sensor yet. Does anyone know what temperature element is used? If the problem isn't with the temperature sensor, I can only think that the controller is faulty. Does anyone know how I can check this & is there anything I should look out for?
Your assistance would be greatly appreciated.

Richard, April 2010

essa geladeira Bosch kdn 47 é uma porcaria, tenho uma desde nova só problema, e uma assistencia técnica fraca, vai trocando pra ver se da certo, maltita hora que sai da brastemp, assistencia técnica ótima, compra peça no balcão, não tem frescura,de querer segurar serviço para o serviço autorizado, e cobrarem quanto quer, pois o atendente da loja fala na cara, quero ver onde vc vai achar peça de substituição se não for instalada por nós, do serviço autorizado, depois que sair dessa bosch nunca mais, o negocio da bosch é continuar a fazer peça para veiculos mesmo,pois fazer eletrodoméstico falta muito ainda, atendimento da rede péssimo e técnicos mau qualificados, pelo menos o da minha cidade, das outras não sei. essa minha congela a parte inferior da geladeira e de repente so o freezer funciona, querem trocar a placa que ja foi trocada uma fez, tem 4 anos de uso, e cada serviço autorizado tem um preço da placa, BRASIL!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Valdir de Mello Franco, October 2010

I have now tested the sensor and it is functional. It is NTC & measured around 10k after I had defrosted the coil.

Richard, April 2010

Correction
I meant to say that the freezer coil had frozen up - not the evaporator coil.

Richard, April 2010