HVAC Air Handler Units and Coils 3

Question 1

What does 'superheat' refer to in the context of an evaporator coil?

Accepted Answer

The temperature of refrigerant vapor above its saturation temperature

Answer

Superheat is the number of degrees the refrigerant vapor temperature exceeds its saturation (boiling) temperature at a given pressure at the coil outlet.

Question 2

What is the recommended minimum clearance around an air handler unit for service access?

Accepted Answer

12-18 inches on service side, 6 inches on other sides

Answer

HVAC industry standards typically require 12-18 inches on the service access side and at least 6 inches on other sides for proper maintenance access.

Question 3

Which coil configuration uses two rows of tubes in a 'A' shape to maximize surface area?

Accepted Answer

A-coil (cased coil)

Answer

An A-coil or cased coil uses two slanted coil sections arranged in an A-shape, maximizing heat exchange surface area while fitting within a compact housing.

Question 4

What is the purpose of the blower wheel fins being curved backward (backward-inclined) in an air handler?

Accepted Answer

To improve efficiency and reduce power consumption at high airflows

Answer

Backward-inclined blower wheel fins are non-overloading, meaning they consume less power as airflow increases, improving efficiency compared to forward-curved designs.

Question 5

What is the recommended pH range for condensate drain water in a properly functioning system?

Accepted Answer

5-7 (mildly acidic to neutral)

Answer

Normal condensate drain water is slightly acidic (pH 5-7) due to dissolved CO2, but excessively acidic condensate can indicate microbial growth or system problems.

HVAC - Heating, Ventilation, and Air Conditioning Practice Test

HVAC - Heating, Ventilation, and Air Conditioning Practice Test

HVAC Air Handler Units and Coils 3