HCR 103

which of the following heat distribution methods relies on only natural convection to distribute heated air

• forced-air

• gravity

• hydronics

• all of the above

which of the following is not a basic component of a gas-fired furnace?

• blower motor

• electric resistance heating element

• flue

• heat exchanger

In a condensing furnace, circulating air passes over the _____ before passing over the primary heat exchanger.

• burner

• combustion blower

• flue

• secondary heat exchanger

Secondary heat exchangers are frequently made of stainless steel because they _____ other metals.

• are exposed to temperature that would melt most

• are less likely to warp than heat exchangers made from metal

• can transfer heat much more rapidly that heat exchangers made from

• can withstand corrosive condensate much better

Unlike a noncondensing furnace, a condensing furnace can use _____ for its exhaust flue.

• chimney

• galvanized

• PVC or CPVC

• stainless steel

Noncondensing furnaces typically have an AFUE rating between _____.

• 10% and 25%

• 40% and 60%

• 80% and 90%

• 90% and 100%

Which of the following statements regarding direct- drive blowers is true?

• The blower fan spins at the same speed as the blower motor.

• The blower fan spins faster if it is equipped with a larger pulley.

• The blower fan spins faster if it is equipped with a smaller pulley.

• The blower fan speed is adjusted by varying pressure on the fan clutch.

Which of the following best describes the function of a combustion blower?

• It atomizes the fuel as it enters the combustion chamber.

• It brings fresh air into the combustion chamber and expels combustion gases.

• It compresses the fuel mixture as it enters the combustion chamber.

• It reduces draft in the flue.

The two types of combustion blowers are _____ blowers.

• primary and auxiliary

• downdraft and updraft

• forced-draft and induced-draft

• pre-combustion and post-combustion

If a house is built with the furnace in the basement and the ductwork running above the furnace, a(n) _____ furnace would most likely be installed.

• upflow

• downflow

• horizontal

• sideflow