CFESA Refrigeration Systems 3 — Questions and Answers
Question 1: Which refrigerant requires technicians to hold an EPA Section 608 Type II certification to service?
- R-410A in residential split systems
- R-404A in commercial refrigeration above 50 lbs (Correct answer)
- R-134a in small appliances
- R-22 in window units
Correct answer: R-404A in commercial refrigeration above 50 lbs
EPA Section 608 Type II certification is required for servicing high-pressure commercial and industrial refrigeration systems containing more than 50 lbs of refrigerant.
Question 2: What does a refrigeration system's COP (Coefficient of Performance) measure?
- Compressor efficiency in horsepower
- Ratio of cooling effect to energy input (Correct answer)
- Condenser heat rejection rate
- Refrigerant mass flow rate
Correct answer: Ratio of cooling effect to energy input
COP measures refrigeration system efficiency by dividing the cooling capacity by the power input, with higher values indicating greater efficiency.
Question 3: In a parallel rack refrigeration system used in supermarkets, which component controls refrigerant distribution to multiple display cases?
- Suction pressure regulator
- Electronic expansion valves and case controllers (Correct answer)
- A single TXV for all cases
- Liquid line solenoid on the rack
Correct answer: Electronic expansion valves and case controllers
Electronic expansion valves paired with individual case controllers precisely meter refrigerant flow to each display case in a parallel rack system.
Question 4: The purpose of a crankcase pressure regulator (CPR) valve in a refrigeration system is to:
- Prevent high discharge pressure
- Limit suction pressure entering the compressor during pulldown (Correct answer)
- Regulate oil pressure in the crankcase
- Control head pressure during cold ambient conditions
Correct answer: Limit suction pressure entering the compressor during pulldown
A CPR valve prevents excessive suction pressure from reaching the compressor during initial pulldown, protecting the motor from overload.
Question 5: What causes a compressor to short cycle in a commercial refrigeration unit?
- Oversize expansion valve
- Low refrigerant charge causing rapid pressure equalization (Correct answer)
- Dirty evaporator coil
- High ambient temperature
Correct answer: Low refrigerant charge causing rapid pressure equalization
A low refrigerant charge can cause the low-pressure control to cycle the compressor on and off rapidly as pressures equalize quickly.
Question 6: During a refrigerant leak search on commercial equipment, which method is most effective for pinpointing small leaks in tight spaces?
- Bubble solution
- Electronic leak detector
- Ultrasonic leak detector (Correct answer)
- UV dye with a UV lamp
Correct answer: Ultrasonic leak detector
Ultrasonic leak detectors can pinpoint small refrigerant leaks in confined spaces by detecting the high-frequency sound of escaping gas.
CFESA Refrigeration Systems 3
Which refrigerant requires technicians to hold an EPA Section 608 Type II certification to service?