How to change the parameter settings on the controller on the MDF-25U270 and MDF -40U270
The temperature calibration parameter code is “ot”.
if the actual temperature is higher than display temperature, increase the value.
if the actual temperature is lower than the display temperature, decrease the value.
It is not the in the same ration, for example, if actual temperature is lower 5C, it may ot value may decrease 3.
Here is attached instruction and video that introduce how to entry into factory mode.