On November 11, 2016, the Defendant installed an original air boiler (hereinafter referred to as “instant boiler”) in the underground room located in Gangseo-gu Busan (hereinafter referred to as “instant building”) located in the Gangseo-gu Busan (hereinafter referred to as “instant building”) which was operated by the Plaintiff.

On November 23, 2016, the Plaintiff paid KRW 15,82,280 to the Defendant the sum of KRW 12,00,000 (2,50,000, 2,500, 200, 200, 200, 200, 200, 200, of the boiler installation costs and the value of coal.

However, in the process of using the boiler of this case, there was a phenomenon that the boiler was overheated or the heating of the guest room was not properly conducted.

[Ground of recognition] In light of the facts without dispute, Gap evidence Nos. 1 through 5 (including branch numbers in the case of additional numbers), the basic facts of judgment as to the cause of claim as to Gap evidence Nos. 5-1 and 2, the results of appraisal commission as to appraiser D, and the purport of the whole pleadings, the plaintiff, upon the defendant's recommendation, purchased the boiler of this case in lieu of the previous four-type boiler, instead of the previous four-type boiler, and the previous 4-type boiler, the heat on the specifications of the four-type boiler, which was produced by alternative energy development through a technical cooperation with the defendant, can be acknowledged that the heat on the specifications of the four-type boiler, which was 120,00ccal/h, and the heat necessary for the heating of the building of this case where the guest room was 42, is 86,40ccal/h, or the actual volume of the boiler of this case, is 62,40ccal/h or about 27%, respectively.

Therefore, the Defendant in charge of installing the boiler was obligated to install the boiler of an adequate capacity necessary for the instant building. However, by installing a boiler which does not meet the required capacity, the Defendant erred by preventing the instant boiler from being overheated or from properly heating the instant building. Ultimately, due to the Defendant’s nonperformance, the Plaintiff was unable to achieve the purpose of the contract.