When you have a casserole that comes out of the oven burnt or undercooked, it is probably because the thermostat is faulty. Thermostats control the temperature inside the oven using a thermal bulb. By learning how to replace a thermostat on an oven, you can quickly get your oven working again. You can purchase thermostats for your oven at appliance repair shops and online. Take the model number and brand name of your unit along to make sure you get the correct part.
Unplug the oven range from the electrical wall outlet. Pull the oven away from the wall so that you can access the rear of the oven. Your oven may have anti-tip clips installed in the floor. If so, push the oven back toward the wall, and tip the rear of the oven up to pull it away from the wall.
Go behind the oven to remove the screws that secure the rear panel to the oven using a Phillips-head screwdriver. Carefully remove the rear panel, and set it out of the way, preferably along the back wall.
Use needle nose pliers to remove the wires from the back of the thermostat housing on the control console. Make sure to grab the wires at the metal leads to pull them off the thermostat terminals.
Pull the control knob off the thermostat from the face of the control console. Use a Phillips-head screwdriver to remove the two screws that secure the thermostat housing to the control console.
Go to the front of the oven, and open the oven door. Unclip the thermal bulb attached to the oven liner. Carefully maneuver the rear tip of the thermal tube through the hole in the back oven wall where the capillary tube comes through the oven.
Go back to the rear of the oven and finish pulling the thermal bulb through the back of the oven, and remove the thermostat assembly from the oven. Take the thermostat with you to an appliance repair shop to get a replacement.
Insert the thermal bulb through the back of the oven, and attach the thermostat housing to the control console. Thread the two retaining screws into the thermostat housing from the face of the control console to hold the thermostat in place.
Go to the front of the oven, and continue pulling the thermal bulb through the rear of the oven, and clip it to the oven liner. Close the oven, and go back to the rear of the oven.
Connect the two wires to the oven thermostat housing by slipping the leads over the terminals until they lock into place. Tighten the retaining screws securing the thermostat to the control console and slide the control knob over the thermostat shaft.
Reattach the rear panel of the oven using the retaining screws. Go back to the front of the oven, and slide the oven back against the wall. Plug the oven power cord back into the wall outlet.