Hey Maxime, When this unit reaches the set temperature the flame becomes small in order to maintain the designated temperature. When you open the door to check on your cooking please wait 3-5 seconds for the flame to grow in larger before you close the door to ensure the flame is large enough that the door closing does not put out the flame. Following these guidelines will resolve the issue you are facing. Regarding oven temperatures settings, please read the below information that is also available on our website Forno.ca. This oven is very powerful, it can reach 350F degree in approximately 7 to 10minutes. To avoid burns, please use oven mitts when manipulation oven racks and be careful not to touch the oven door when in use. All knobs may reach 123F when oven is in use – although the standard regulations is max 148F please handle with care. This oven is equipped with a highly efficient convection fan accelerating cook time and distributing heat evenly, therefore cooking time could be up to 20% faster than other non-commercial type ovens using 25F less heat. The convection fan runs continuously except for when using the broil setting. • For more accurate temperature reading, always refer to the knob temperaturesetting. The convection fan creates air movement causing the temperature gauge precision to fluctuate between 10% and 20% a better accuracy is obtained after 70 minutes of operating time. This oven has a safety Thermo-cut-off that will shut gas off automatically if flame goes out. For better Broil efficiency pre-heat to 500F for 8 Minutes and turn the knob to broil until you see the flame and wait 3 to 4 seconds before releasing. When using the oven, push and turn the oven knob counter-clockwise to the desired temperature (ex: 325°F) and hold until the oven burner ignites. As it ignites, wait 5 to 10 seconds before releasing the knob. Note that the flame will be large for the whole preheating process. Once preheated, the flame will automatically decrease in size, indicating the oven is ready for cooking. Open the door, place the food inside the oven and wait until the flame is visibly larger before closing back the door (this may take a few seconds). The oven is designed to maintain the original selected cooking temperature. If a lower cooking temperature, than the original preheating setting is desired, the oven needs to be re-lit manually by repeating the steps above.