Solder joints are used in applications where the maximum temperature of the liquids is _____.

Solder joints are used in applications where the maximum temperature of the liquids is _____.
 
  a. 100F
  b. 200F
  c. 250F
  d. 300F

 Q. 2

How does negative pressure affect the air supply of a furnace?
 
  A) It causes little noticeable changes to a furnace. B) It increases the furnace's need for gas.
  C) It causes a need for less outside air. D) It increases the need for outside air.

 Q. 3

What causes flue gas condensation?
 
  A) operating the furnace during times of high relative humidity
  B) cold air being pulled through the vent on the off cycle drops the vent temperature below the dewpoint of the surrounding air
  C) the flue gas is cooled below the dewpoint of the combustion gas
  D) water naturally condenses on metal surfaces