CFC Commercial Refrigeration Systems 5

Question 1

A commercial refrigeration technician is replacing a hermetic compressor. After the repair, the system must be evacuated to at least:

Accepted Answer

500 microns

Answer

EPA and industry standards require deep evacuation to 500 microns or lower to ensure all moisture and non-condensable gases are removed before recharging.

Question 2

Which factor most determines the condensing temperature in an air-cooled commercial refrigeration system?

Accepted Answer

Ambient air temperature at the condenser

Answer

In air-cooled systems, the ambient temperature at the condenser sets the lower limit for condensing temperature, as heat must flow from refrigerant to the surrounding air.

Question 3

A technician wants to add refrigerant to a commercial system that uses R-404A. How must this blend be charged?

Accepted Answer

As liquid only, since it is a near-azeotropic blend

Answer

R-404A is a near-azeotropic zeotropic blend; charging as liquid ensures the correct mixture ratio is maintained, since vapor charging can cause fractionation.

Question 4

In a large commercial refrigeration system, a desuperheater is used primarily to:

Accepted Answer

Remove superheat from discharge gas to recover heat for water heating

Answer

A desuperheater extracts heat from hot discharge gas to heat water, recovering waste heat and improving overall system efficiency.

Question 5

What is the purpose of a crankcase pressure regulator (CPR) valve in a commercial refrigeration system?

Accepted Answer

Limit suction pressure to the compressor during high-load pulldown

Answer

A CPR valve limits the suction pressure entering the compressor during high-load pulldown conditions to prevent motor overload and compressor damage.

(CFC) Chlorofluorocarbon Certification Practice Test

(CFC) Chlorofluorocarbon Certification Practice Test

CFC Commercial Refrigeration Systems 5