The heater water tank or water valve is faulty.
One of the reasons why the air conditioner can't produce hot air may be that the heating box or water valve is out of order. You can check the hot air tank and hot air valve to see if they need to be repaired or replaced.
Engine temperature is too low
Sometimes, the engine has just started and the temperature is still relatively low. At this time, the temperature of the refrigerant is also relatively low, so cold air is blown out after the air conditioner is turned on. You can wait a while for the engine and coolant to warm up and try again.
Indoor fan failure
When the air conditioner is heating, it is necessary to check whether the indoor fan is running. It is normal to start heating without blowing, but if there is no blowing for a long time, it may be that the internal fan is faulty. If the air is cold, it may be that the outdoor unit is not working, or the four-way valve is out of order, resulting in no heating.
External machine failure
If the external machine is not running, it may be the fault of the external machine itself or the component of the control circuit. In this case, it is recommended to find after-sales service, check electrical failure or leakage, and add fluoride.