Did you know that it’s common to find an oven’s temperature can be off by more than 50°F? Thermostats become fatigued with age. Leaky door seals can cause hot or cool spots that affect the thermostat. For best results with your oven, use the PAT550 to monitor the exact oven temperature. The PAT550 is oil-filled for delayed response so that the temperature reading is not affected by oven cycling and when opening the oven. Note: Allow 15 minutes for the first accurate temperature reading.