The thermostat bulb is the mechanism that tests the inside temperature of the oven to ensure it remains consistent. If the bulb is broken or loose it will not operate correctly. Twist the bulb clockwise to tighten it and ensure a strong connection. Replace the bulb if it is broken.
Some ovens have only one broiler setting, but many have multiple settings that allow you to slowly roast vegetables, melt cheese or heat food. Because the oven’s heating element is on, it will heat up the oven. If you leave it on for too long, the oven will get very hot and it could accidentally cook the food or burn it. Avoid this by leaving the oven door slightly open when you have your broiler on.
The oven’s sensor may be broken, it may not be calibrated correctly or may have been defective in the first place. The sensor receives electrical information from the thermostat bulb and sends it to the control panel that turns the heating elements on or off. If the sensor is broken or if it isn’t calibrated properly, it may register a lower temperature and signal the oven to increase the temperature.
Many ovens have an electronic control panel that allows you to calibrate the oven. The process for calibration will vary depending on your oven’s make and model, but generally there is a button on the panel that will allow you to lower the adjusted calibration of the oven.