1970. 3. Daeyeol Boiler Factory was established.
1974. 5. Acquired license to produce heat-using equipment.
1977. 1. Moved factory to a larger facility located in 1001-4, Doksan-dong, Guro-gu, Seoul.
1977. 9. Began production and sale of boilers for ships. (The navy)
1980. 3. Received type approval for all the items of flue tubular boiler.
1981. 2  Signed on a contract with Parkinson Boiler of the U.K. for introduction of technology.
1982. 10. Registered as an a partner of Chosun Industry.
1983. 9. Signed on a contract with Maeda Ironworks Co. in Japan for introduction of technology.
1987. 5. 2nd technological partnership with Maeda Ironworks
1989. 2. Completed construction of the 2nd factory in Banwol, Gyeonggi-do.
1989. 9. Developed Super-mini Boiler (flue tubular boiler).
1992. 6. Developed no pressure water spray hot  water boiler.
1995. 6. Developed condensing boiler (high-efficiency boiler).
1996. 12. Developed new super-mini boiler (super efficient flue tubular boiler).
1997. 8. Reveived EM certification for condensing boiler.
1998. 1. Certified by ISO 9001.
1998. 11. Condensing boiler received “Energy Winner Award”.
1999. 10. Conensing boiler certified as a “highly efficient machine”. }
2000. 3. Acquired China’s CSQL.
2000. 9. The company name was changed to “Daeyeol Boiler Co., Ltd.”. }
2001. 9. Condensing boiler received a “Certificate of superior product by Public Procurement Service”.
2004. 12. Developed inverter condensing boiler.
2005. 3. Certified by ISO14001.
2005. 9. Acquired NET new technology certificate (Ministry of Science & Technology).
2005. 10. Awarded for Industrial Medal of Merit (Ministry of Commerce, Industry & Energy).
2006. 3. Inverter condensing boiler received a “Certificate of superior product by Public Procurement Service”.
2006. 7. Inverter condensing boiler received “Energy Winner Award”.
2007. 7. Established the research institute attached to the company.
2008. 10. Acquired INNO-BIZ certificate.
2009. 4. Low carbon condensing boiler received a “Certificate of superior product by Public Procurement Service”.