CFC Commercial Refrigeration Systems 3

Question 1

In a commercial display case, what is the primary function of the anti-sweat heaters on door frames?

Accepted Answer

Prevent condensation on door frames and gaskets

Answer

Anti-sweat heaters warm door frames and glass edges above the dew point to prevent condensation that would obstruct customer view and cause corrosion.

Question 2

What refrigerant charge condition is indicated when both suction and discharge pressures are lower than normal in a commercial system?

Accepted Answer

System undercharged or low refrigerant

Answer

Low refrigerant charge reduces mass flow rate, causing both suction and discharge pressures to fall below normal operating levels.

Question 3

Which type of defrost cycle is most energy-efficient for commercial refrigeration cases operating near freezing temperatures?

Accepted Answer

Off-cycle defrost

Answer

Off-cycle defrost simply stops the refrigeration cycle and allows ambient heat to melt frost, consuming no additional energy compared to electric or hot gas methods.

Question 4

A technician finds oil logging in the evaporator of a commercial refrigeration system. What is the most likely cause?

Accepted Answer

Insufficient refrigerant velocity to carry oil back to compressor

Answer

Oil logging occurs when refrigerant velocity is too low to entrain oil and return it to the compressor, often from oversized piping or low load conditions.

Question 5

In commercial refrigeration, a thermostatic expansion valve (TXV) bulb should be mounted on the suction line:

Accepted Answer

At the 4 or 8 o'clock position on a horizontal suction line

Answer

Mounting the TXV sensing bulb at the 4 or 8 o'clock position on a horizontal suction line ensures it senses refrigerant temperature accurately without being affected by oil pooling at the bottom.

(CFC) Chlorofluorocarbon Certification Practice Test

(CFC) Chlorofluorocarbon Certification Practice Test

CFC Commercial Refrigeration Systems 3