Static pressure readings are taken on a duct system by :

Static pressure readings are taken on a duct system by
 
  A) Pointing the pressure sensing tube into the airstream
  B) Subtracting the total pressure from the velocity pressure
  C) Subtracting the velocity pressure from the total pressure
  D) Pointing the pressure sensing tube perpendicular to the air stream

 Q. 2

Velocity pressure readings are taken on a duct system by
 
  A) Subtracting the static pressure from the total pressure
  B) Pointing the pressure sensing tube perpendicular to the air stream
  C) Pointing the pressure sensing tube into the airstream
  D) Subtracting the total pressure from the static pressure

 Q. 3

Which of the following is not part of the operating sequence of a natural-draft furnace?
 
  a. The draft inducer starts on a call for heat.
  b. The controls prove that the pilot is lit.
  c. The gas valve energizes and opens.
  d. The fan switch starts the blower.