UNIT 45 CHAPTER REVIEW EXAM QUESTIONS

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UNIT 45 CHAPTER REVIEW EXAM QUESTIONS

Actual Qs and Ans Expert-Verified Explanation

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-Guarantee passing score -34 Questions and Answers -format set of multiple-choice -Expert-Verified Explanation Question 1: What is the industry standard rate of through-the-evaporator airflow in CFM per ton for most air-conditioning equipment?

Answer:

400 CFM per ton

Question 2: What gauges are used for measuring duct pressure?

Answer:

Magnehelic gauges Question 3: A type of fan that is designed for producing high static pressure in a duct

distribution system is:

Answer:

Centrifugal.Question 4: To use a fan curve, you need to know:

Answer:

The required CFM and the static pressure the fan must operate against.

Question 5: The relationship of CFM and FPM can be summarized as:

Answer:

CFM = FPM × area.Question 6: Total pressure readings are taken on a duct system by:

Answer:

Pointing the pressure-sensing tube into the airstream.Question 7: Static pressure readings are taken on a duct system by:

Answer:

Pointing the pressure-sensing tube perpendicular to the air stream.Question 8: Velocity pressure readings are taken on a duct system by:

Answer:

Subtracting the static pressure from the total pressure.Question 9: AMCA fan performance classifications are based on:

Answer:

The upper and lower ranges of static pressure and outlet velocity.Question 10: Technicians should know that fan speed is directly related to the amount of air a fan can move; therefore, doubling the fan speed will ________ the amount of air flow.

Answer:

double Question 11: If the air inlet to a centrifugal fan is restricted:

Answer:

The fan motor current draw will decrease.Question 12: In order to double fan RPM, the motor horsepower:

Answer:

Must increase by a factor of 8 (2 × 2 × 2).

Question 13: Airflow through an axial fan is:

Answer:

Parallel to the fan shaft.Question 14: The speed of air is measured in:

Answer:

Feet per minute - FPM.Question 15: The two basic types of fans used in most air-handling units are:

Answer:

Centrifugal and axial.Question 16: The speed of air is measured in:

Answer:

400 CFM per ton.Question 17: The most common fan used for moving air through ductwork in residential air

conditioning is:

Answer:

Forward-curved centrifugal.Question 18: Three types of fan blades used with centrifugal fans include:

Answer:

Forward-curved, backward-curved, and backward-curved airfoil.Question 19: The three common types of axial fans are:

Answer:

Propeller, vane axial, and tube axial.Question 20: What fan performance characteristics are shown on a typical fan curve?

Answer:

Pressure drop, efficiency, and horsepower

Question 21: What pressure units are used for measuring duct pressures?

Answer:

Inches water column Question 22: The Air Movement and Control Association, AMCA, has established:

Answer:

The Fan Energy Index (FEI).Question 23: If a technician wanted to accurately measure static pressure in a duct system, how would she place the sensing probe of the magnehelic gauge?

Answer:

Perpendicular to airflow Question 24: The Fan Energy Rating (FER), requires most furnaces to:

Answer:

Operate at or below the wattage stated in the FER ruling.Question 25: The quantity of air a blower is moving is measured in:

Answer:

Cubic feet per minute - CFM.Question 26: The advantage of the backward-curved centrifugal fan over the forward-curved

centrifugal fan is that:

Answer:

Backward-curved fans are non-overloading.Question 27: The two broad types of fan designs are:

Answer:

Centrifugal and axial.Question 28: What is the CFM of air moving through an 8 in × 10 induct if the air velocity is 800 FPM?

Answer:

• × 10 = 80 sq in, 80/144 = 0.56 sq ft, 800 × 0.56 = 444 CFM