| 摘要 |
PROBLEM TO BE SOLVED: To provide a heating system that can perform heating operation by a heating terminal machine for performing heat radiation while performing defrosting operation of a heat pump unit with a small system constitution and at low cost.SOLUTION: When occurrence of necessity of performing defrosting operation of a heat pump unit 3 during heating operation is predicted, before starting the defrosting operation, pre-defrosting operation control means 5a executes control so as to increase the temperature of a heat medium for heating supplied to a heating terminal machine 1 in a heat medium circulation passage 2, and after the temperature of the heat medium for heating rises to a predetermined temperature or more, the defrosting operation of the heat pump unit is performed. |
