How does venting compare on 80 percent and 90 percent efficient ...

[saliriagwu]

How does venting compare on 80 percent and 90 percent efficient heating units?
 
  A) 90 furnace vents are 10 larger in size than 80 furnace vents
  B) 80 units require outside air to be piped in for combustion and 90 do not
  C) 80 furnaces use PVC vent and 90 furnaces use type B gas vent and
  D) 80 furnaces use type B vent and 90 furnaces use PVC pipe for venting material

Question 2

What controls the amount of gas entering the burner?
 
  A) The gas manifold pressure and the burner venture size
  B) The gas valve
  C) The draft created by the gas flames
  D) The gas manifold pressure and the burner orifice size

[DHRUVSHAH]

Answer to Question 1

D

Answer to Question 2

D

[saliriagwu]

TYSM

[Viet Thy]

Excellent