Forced air heating system

摘要

The flue pipe for a combustion chamber of a hot air furnace passes through the hot air plenum and then passes through the cold air supply duct. Heat exchange fins are secured to a length of the flue pipe located within the hot air plenum and within the cold air supply duct to utilize the residual heat of the flue gases to heat the air flowing around the fins. The flue pipe extends to a chimney for exhausting the gases. A sensor is located for response to the temperature of the air heated by both the flue pipe passing through the hot air distribution header and the furnace itself for energizing a driven blower. A thermostat produces a command signal to deliver fuel to the furnace burners. The blower is energized when the temperature in the hot air plenum reaches a predetermined level.