There are many reasons for this situation, which can be explained by several situations. 1. If it's still like this after buying it back, it should belong to the manufacturer's production problem, and the nozzle may not match. If it takes a long time for this reason to appear, it may be that the burner of the fire cover is blocked.
Another point to note, which is also the most important point, is that some manufacturers deliberately set the firepower very large or very small in design to meet the special requirements of some customers. If you can't solve it by yourself, please consult the merchant before operating.