Problem with electric oven temperature control

A brand and model number may get you more responses.

The typical oven thermostat uses a bulb type thermometer/thermostat that feeds a diaphragm or Bourdon tube back at the control. Bourdon tube is a coiled flattened tube that wants to straighten out when pressure is applied to it.

Most ovens still use a fluid filled bulb that transmits pressure directly back to a pressure switch located in the control. When you turn the knob on the control, you are adjusting a cam that changes the position of the contacts inside.

The sensor/sender is a larger copper tube (the bulb portion) that feeds into a capillary copper tube (your large copper wire - is a tube) that runs to the control.

To calibrate it - There are two methods that are used.

One is the knob pointer itself - pull the knob off and look at the back of it. There will be a screw and slot that allows the pointer to move (with respect to the knob and shaft) set it higher to reflect the actual temperature. (the temperature scale is part of the control panel - and the knob only fits the shaft in one orientation only - "half moon" flatted shaft)

The second method is a pair of slotted holes in the control panel that allow the whole control to change position with respect to the scale - adjust it to reflect the real temperature.