Problem with electric oven temperature control

[fl]

Hi,
The baking part of my electric oven is out of temperature control. That
is, the temperature is always higher than I set. I find the temperature
sensor on the back of the oven does not hold rigidly. Today, I
unscrewed the four screws of an iron plat in the back of the oven. I
found the thick copper wire from the sensor was loose. And the wire is
a single one, there is a quite some length bare copper wire in a bundle
before the last covered green plastic. I wonder the stick sensor just
conduct temperature, not electrical signal?
The upper four coils work fine. What's the problem with the baking
temperature control?
I did not find the content in the website of
http://repairfaq.ece.drexel.edu/REPAIR/


Thanks in advance

 

[Warren Weber]

Hi,
The baking part of my electric oven is out of temperature control. That
is, the temperature is always higher than I set. I find the temperature
sensor on the back of the oven does not hold rigidly. Today, I
unscrewed the four screws of an iron plat in the back of the oven. I
found the thick copper wire from the sensor was loose. And the wire is
a single one, there is a quite some length bare copper wire in a bundle
before the last covered green plastic. I wonder the stick sensor just
conduct temperature, not electrical signal?
The upper four coils work fine. What's the problem with the baking
temperature control?
I did not find the content in the website of
http://repairfaq.ece.drexel.edu/REPAIR/


Thanks in advance

A brand and model number may get you more responses.

 

[default]

Hi,
The baking part of my electric oven is out of temperature control. That
is, the temperature is always higher than I set. I find the temperature
sensor on the back of the oven does not hold rigidly. Today, I
unscrewed the four screws of an iron plat in the back of the oven. I
found the thick copper wire from the sensor was loose. And the wire is
a single one, there is a quite some length bare copper wire in a bundle
before the last covered green plastic. I wonder the stick sensor just
conduct temperature, not electrical signal?
The upper four coils work fine. What's the problem with the baking
temperature control?
I did not find the content in the website of
http://repairfaq.ece.drexel.edu/REPAIR/


Thanks in advance

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.