Complete assembly boilers, as opposed to traditional loose assembly boilers, are assembled at the factory after the boiler body and components are delivered to the site. In contrast, complete assembly boilers, in addition to basic components, also include the base and supports, which are already assembled and secured with the base and supports at the factory. Upon arrival at the site, only overall installation and connection of external pipelines are required, significantly reducing the installation time on-site compared to loose assembly boilers, while also improving the quality of the boiler installation.