A heat exchanger is bad if gas leaks from one side of the heat exchanger to the other. In other words if the exhaust gases from the flames are allowed to enter your home, or vise versa. Certification ensures that the heat exchanger is not leaking. In most cases you need to replace the furnace.
ODIN technologies. ODIN provides RFID (Radio-Frequency Identification) software and solutions for the Aerospace, Government, Healthcare, Financial Services and Social Media markets. ODIN's world headquarters is located in San Diego, CA. ODIN was acquired by Quake Global in December 2012 and continues to focus on healthcare and asset tracking.
Asgard itself was home to many realms inside its boundaries including Valhalla and more. Asgard was located in the middle of the Viking world, and on the highest rung of the Norse universe. It was populated by the elite gods the Aesir, including such as Odin, his wife Frigg, Thor and many more.