Hot water circulation device and hot water device monitoring system

A hot water circulation device, comprising:

• a circulation passage for heated hot water;
• a circulation pump for circulating the hot water in the circulation passage;
• a closed expansion tank in which a water chamber communicating with the circulation passage and an air chamber filled with a predetermined pressure in an initial state are partitioned by a diaphragm;
• and a control unit for controlling circulation of the hot water, the hot water circulation device comprising:
• an air chamber pressure sensor for detecting a pressure in the air chamber of the expansion tank;
• a closing valve for cutting off the water chamber from the circulation passage;
• and an opening valve capable of opening to an atmosphere from between the closing valve and the water chamber,
• wherein the control unit closes the closing valve and opens the opening valve during circulation of the hot water, detects the pressure in the air chamber by the air chamber pressure sensor, and issues a warning notification when the pressure in the air chamber is not within a predetermined pressure range.