Ok I have a question on the newer wall ovens that utilize hall sensors to monitor the fan speed along with the relay boards.
The latest issue is the above mentioned H398BP2 Miele oven. Upper oven does not heat. The cooling fan runs I have 120 volt out of relay board.This unit has a seperate relay to switch the other leg of power which is activated by 12 vdc from the power electronic ( I would call it a relay board). I do not have 12vdc to the relay. Is it the board or the cooling fan sensor?
I spoke to mfr techline and was suggested to replaced the power electronic at a cost of $800.00 for part. When I went through service manual I found this pearl of wisdom.
" All oven cooling fans (including speed ovens) are equipped with a
speed sensor. This sensor is a Hall-effect semiconductor device and
its proper operation cannot always be determined using a multimeter. If
an oven refuses to heat, always remember to check the operation of
the cooling fan at all available speeds. If the electronic does not detect
a signal from the fan, the main heater relay (1K1, 2K1) will not
What ?? I asked the techline rep about this and told me he didn't know of any way to test the sensor on the fan. I have had a couple of Thermadors where the only way I could get the unit to work was replacing relay board and the cooling fan. Tried independantly but only worked with both new components. How do these mfr's get away with this stuff ! I have to quote my customer it's this much but it may be this much more if that doesn't work. Makes me sound professional doesn't it. Sorry but after 30 years of this crap when I think I've seen it all it just gets worse!