CFC HVAC Systems & Leak Detection 2 — Questions and Answers
Question 1: Which leak detection method uses a flame that changes color in the presence of halogenated refrigerants?
- Electronic detector
- Halide torch (Correct answer)
- UV dye method
- Ultrasonic detector
Correct answer: Halide torch
A halide torch produces a blue-green flame color change when halogenated refrigerants (CFCs, HCFCs) are present in the air sample.
Question 2: What is the minimum leak rate threshold that requires repair under EPA Section 608 for comfort cooling equipment containing 50 or more pounds of refrigerant?
- 5% per year
- 10% per year
- 15% per year (Correct answer)
- 20% per year
Correct answer: 15% per year
EPA Section 608 requires repair when comfort cooling appliances with 50+ lbs of refrigerant leak at 15% or more of the charge per year.
Question 3: In a split-system air conditioner, which component is most likely to cause refrigerant leaks due to vibration fatigue?
- Expansion valve orifice
- Copper refrigerant line near the compressor (Correct answer)
- Condenser fan blade
- Filter drier shell
Correct answer: Copper refrigerant line near the compressor
Copper refrigerant lines near the compressor experience metal fatigue from compressor vibration, making them a common site for pinhole leaks.
Question 4: When using an electronic leak detector, what action should a technician take first upon entering a suspected leak area?
- Immediately probe all fittings
- Allow the detector to warm up and stabilize (Correct answer)
- Disable all ventilation fans
- Set the sensitivity to maximum
Correct answer: Allow the detector to warm up and stabilize
Electronic detectors require a warm-up period to stabilize their sensors and provide accurate, reliable readings.
Question 5: A technician finds the suction pressure lower than normal and the superheat higher than normal. Which condition is most likely?
- Refrigerant overcharge
- Compressor valve failure
- Refrigerant undercharge due to leak (Correct answer)
- Condenser fouling
Correct answer: Refrigerant undercharge due to leak
Low suction pressure combined with high superheat is a classic symptom of insufficient refrigerant, typically caused by a system leak.
Question 6: What type of refrigerant circuit component is specifically designed to trap moisture and acid and should be replaced after any refrigerant leak event?
- Sight glass
- Accumulator
- Filter drier (Correct answer)
- Liquid line solenoid
Correct answer: Filter drier
A filter drier absorbs moisture and acid; after a leak allows air/moisture entry, the saturated drier must be replaced to protect the system.
Question 7: Under EPA regulations, which of the following refrigerants requires the LOWEST leak rate threshold before mandatory repair for industrial process refrigeration?
- R-11
- R-22
- R-134a
- All ozone-depleting refrigerants have the same threshold (Correct answer)
Correct answer: All ozone-depleting refrigerants have the same threshold
EPA Section 608 applies the same 35% annual leak rate threshold for industrial process refrigeration regardless of the specific ODS refrigerant.
CFC HVAC Systems & Leak Detection 2
Which leak detection method uses a flame that changes color in the presence of halogenated refrigerants?