Pairing system for remotely managing hot-water utilization facility and communication adapter used in system

A communication adapter communicably connected to a hot-water utilization facility via a communication line and adapted to establish a wireless link to a wireless LAN router connected to a communication network, so as to be communicably connected to an administration center for remotely monitoring and/or remotely operating the hot-water utilization facility via the wireless LAN router,

• the communication adapter adapted to function as an access point for providing a direct wireless communication with a mobile wireless communication terminal,
• wherein the communication adapter is configured, with the mobile wireless communication terminal having established a wireless link in the direct wireless communication, in response to a request from the mobile wireless communication terminal via the direct wireless communication, to provide a predetermined pairing authentication information to the mobile wireless communication terminal via the direct wireless communication;
• in response to a request from the mobile wireless communication terminal or autonomously when providing the pairing authentication information, to initialize wireless LAN connection for a wireless link to the wireless LAN router in order to disconnect the wireless link to the wireless LAN router;
• and,
• when the wireless LAN connection is set after the initialization, to establish a wireless link to the wireless LAN router and transmit the pairing authentication information to the administration center via the wireless LAN router.