Why is there no heating in the van?

The principle of air conditioning and heating for vans and other family cars is basically the same. There is no warm air for the following reasons: 1. Hot water will not reach the hot air tank. Among them, the heating water pipe is blocked and the hot water valve is faulty. This fault can be realized only by touching two warm water pipes in front of the warm water valve in the engine compartment. If one is hot and the other is cold, there is something wrong with the warm water or the warm water piping system. 2. Hot air will not be sent out from the air outlet. Among them, the air conditioning filter element is blocked, the air conditioning heater door is stuck, the control cable falls off or the control motor fails, and the air supply volume of the blower is too small.