To provide a heating system reducing damage of an apparatus due to freezing by carrying out circulation of working fluid for preventing freezing as much as possible.

The heating system is equipped with a controller 100 carrying out determination of prohibiting circulation of fluid for heat radiation when an amount of the fluid for heat radiation stored in an expansion tank 7 is a predetermined amount or less. In the controller 100, a circulation propriety determination process is carried out of determining whether or not it is an allowable state of being able to circulate the fluid for heat radiation by a fluid for heat radiation circulation circuit 9 other than the determination of prohibiting circulation of the fluid for heat radiation on the basis of the amount of fluid for heat radiation stored in the expansion tank 7, and even if it is determined that circulation of the fluid for heat dissipation is prohibited on the basis of the stored amount of the fluid for heat radiation, if it is determined that it is in the allowable state by the circulation propriety determination process, operation of a pump 10 is controlled so as to circulate the fluid for heat radiation.

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