Heller OVH28 / OVH48

I followed instructions to heat the oven and burn away any dust. Once heated the fan made a terrible noise. I sent it back for a replacement. I did the same with the replacement and had hopes... I soon realised the thermostat was cutting in and out no...

Purchased 3 months ago, we have used it 2 or 3 times a week , works well is quiet, the power light do sent go out when temperature is reached, which is a bit strange.The dials give good info, and the fan can be used on all settings or turned off.