E5 stands for wind pressure fault. The inspection method is as follows: Observe whether the water heater is on fire. If the burning flame pattern does not appear or goes out after a while, E5 will be displayed, indicating that the air pressure switch is broken or the flue is blocked. If you unplug the flue directly, try again. It is normal. The problem lies in the flue. If it is not normal, the wind pressure switch is broken. If water is boiled, there is only a shower icon on the water heater, but there is no fan icon, and the controller or capacitor is broken.