1. The surface of the heating tube is red when it reaches 400 degrees. Because the heating is continuous heating at the beginning, the surface temperature of the heating tube is as high as the red temperature of the heating tube. After the temperature is stable, the heating tube is intermittently heated, so the temperature cannot reach the redness temperature requirement, as long as the heating is normal. 2. If there is no heating, the heating tube inside the oven is not red when it is energized, indicating that the heating tube is not working. (1). You can first check whether there is a problem with the wiring, if there is a correct wiring first; (2). If it is confirmed that there is no redness under the condition of normal power on, the heating tube is damaged; (3). If the heating tube is only part of the area Red, indicating that the heating of the heating tube is uneven, which will affect the service life. Extended information: 1. Working principle Electric oven uses electricity to make roast chicken, roast duck, toast bread, pastry, etc. According to the different needs of baked food, the temperature of the electric oven can generally be adjusted in the range of 50-250 ℃. The electric oven is mainly composed of a cabinet, an electric heating element, a thermostat, a timer and a power adjustment switch. The box body is mainly composed of a three-layer structure composed of an outer shell, a middle partition and an inner liner. The front and back sides of the inner liner are formed with curling edges to cut off the air in the cavity; the outer cavity is filled with insulating expanded perlite products to make the outer shell The temperature is greatly reduced; at the same time, the spring structure is installed under the door, so that the door is always pressed tightly on the door frame, so that it has better sealing. The heating method of the electric oven can be divided into three types: surface heating and upper and lower heating at the same time. Second, the scope of application of hot air circulation oven is suitable for heating, solidification, drying and dehydration of materials and products in pharmaceutical, chemical, food, agricultural and sideline products, aquatic products, light industry, heavy industry and other industries. Such as APIs, Chinese medicines, Chinese herbal medicines, extracts, powders, granules, granules, water pills, bottles, pigments, dyes, dehydrated vegetables, dried melons and fruits, sausages, plastic resins, original electrical appliances, and baking varnish. Hot air circulation ⒈ commonly used steam pressure 0.2 ~ 0.8Mpa (2 ~ 8KG). ⒉Heating heat source steam, electricity, far infrared, electric steam is used on both sides for users to choose. ⒊Use temperature: steam heating 50 ~ 140 ℃, up to 150 ℃. ⒋Power consumption, far infrared temperature 50 ～ 300 ℃. ⒌ There are three kinds of materials: carbon steel, aluminum plate and stainless steel.