When blowing cold air, use a semiconductor refrigerator to cool and blow cold air; Hot air is the electric heating device in the machine, which will work, usually electric heating wire, infrared heating tube, PTC ceramic heating element and so on. The wind from the fan passes through the heating element and becomes hot air.

In view of the fact that the cooling and heating fan only produces cold air but not hot air, there may be the following reasons:

There is a setting switch in the power connection of the heating wire, which cannot be turned on only by energizing the heating and cooling fan;

Poor contact of electric heating element;

When the electric heating tube melts, the electric heating wire needs to be replaced;

The cooling and heating fans are not set in the warm air position;

Something is wrong with the thermostat.

If you want to solve the problem, find out the problems according to the above reasons and prescribe the right medicine one by one.