HVAC Air Conditioning 3

Question 1

What condition is indicated when a technician measures frost forming uniformly across the entire evaporator coil surface?

Accepted Answer

Low airflow across the coil

Answer

Uniform frost across the entire evaporator typically indicates insufficient airflow, causing the coil temperature to drop below 32°F across its full face.

Question 2

Which refrigerant replaced R-22 as the standard for residential air conditioning in the United States?

Accepted Answer

R-410A

Answer

R-410A (sold under brand names like Puron) became the replacement for R-22 in residential AC systems due to its zero ozone depletion potential.

Question 3

What is the function of a crankcase heater on a compressor?

Accepted Answer

Prevent refrigerant migration and dilution of oil during the off cycle

Answer

A crankcase heater keeps the compressor oil warm during the off cycle to prevent liquid refrigerant from migrating into the crankcase and diluting the lubricant.

Question 4

A technician measures a temperature split of 14°F across the evaporator (return air 75°F, supply air 61°F). What does this suggest?

Accepted Answer

Normal operation for a properly sized system

Answer

A temperature split of 14-22°F across the evaporator coil is generally considered normal for a properly operating air conditioning system.

Question 5

What is the purpose of the filter-drier in an air conditioning system?

Accepted Answer

Remove moisture and contaminants from the refrigerant

Answer

The filter-drier removes moisture (which can cause acid and freeze-ups) and solid contaminants from the refrigerant circuit.

HVAC Practice Test

HVAC Practice Test

HVAC Air Conditioning 3