Why do gas furnace efficiencies jump from 80 percent to 90 ...

[cmoore54]

Why do gas furnace efficiencies jump from 80 percent to 90 percent?
 
  A) The blower used with 85 percent furnaces cannot be used for air conditioning.
  B) Federal regulations do not allow the production of mid-efficiency furnaces.
  C) By installing a recuperative coil ahead of the main heat exchanger.
  D) The physics of combustion make it impossible to produce an 85 percent efficient furnace.

Question 2

What problems can be caused by overlubricating a blower motor?
 
  A) The blower motor could run faster than specifications recommend.
  B) The motor would run more effectively with the extra lubrication.
  C) This could eventually cause the motor windings to short out.
  D) It is not possible to overlubricate a motor.

[Mholman93]

Answer to Question 1

C

Answer to Question 2

C

[cmoore54]

Excellent

[apple]

Thanks for the timely response, appreciate it