Stoves Rotostar gas oven temp calibration – Q 600 GRF

Hi,

Model number is 059050025

I believe this was installed in the flat I live in in maybe 10 years or so ago (before I moved in).

The temperature in the oven was always too low but I just lived with it, increasing the gas mark setting accordingly.
But the other day I thought I’d look into it more closely using a oven thermometer.

With the cover plate to the control panel off I was able to stick some number stickers onto the actual indicator disc when the oven had reached the right temperature for that gas mark (allowing for a reduction because it is a fan oven). I used stickers from VHS video labels (remember those?!!)

This is the result:

So it always seems to be out by a consistent margin and it *can* reach the highest gas mark within the range of travel of the knob, which I thought was strange.

Then I noticed the part number printed on the centre of the indicator disc says: “GR 900 main oven”. This whole oven range is discontinued but from what I can tell, the 900 used to be a dual oven (hence the words ‘main oven’):

Is it possible that Stoves has simply fitted the wrong indicator disc? Or alternatively, is this a common part across the 600 / 900 models (in respect of the main oven at least) and the oven thermistor is just consistently out? I would have thought if the oven thermistor had “gone”, it wouldn’t have done so in such a uniform way.

Was hoping someone could shed some light on this. Thanks in advance!