HVAC Systems & Leak Detection Flashcards
7 cards from real CFC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 HVAC Systems & Leak Detection flashcards as text
What is 'formicary corrosion' and why is it significant for HVAC leak detection?
Answer: A form of copper corrosion caused by formic or acetic acid producing pinhole leaks
Formicary corrosion is caused by organic acids (formic, acetic) reacting with copper in the presence of moisture, creating characteristic tunnel-like pinholes that leak refrigerant.
When recovering refrigerant from a system suspected of having a large leak, what precaution is most important before beginning recovery?
Answer: Identify the refrigerant type to use the correct recovery equipment and cylinders
Identifying the refrigerant type is critical to avoid cross-contamination, use correct recovery equipment rated for that refrigerant, and comply with handling regulations.
A technician measures compressor discharge temperature significantly above normal while suction pressure is below normal. What refrigerant system fault does this suggest?
Answer: Low refrigerant charge causing high compression ratio and superheat
A low charge increases the compression ratio and allows excessive superheat to reach the compressor, raising discharge temperature well above normal.
Which EPA record-keeping requirement applies when more than 50 pounds of refrigerant is added to a system during the calendar year?
Answer: The owner must maintain records of the refrigerant added and leak inspections performed
EPA Section 608 requires owners of appliances with 50+ lbs of refrigerant to keep records of refrigerant added and to document leak inspection dates and results.
In a heat pump system operating in heating mode, which pressure side should a technician probe first when searching for leaks using an electronic detector?
Answer: High-pressure discharge side, since higher pressure drives refrigerant through leak paths faster
Higher system pressure on the discharge side forces refrigerant through any existing leak path more rapidly, making leaks more detectable on the high side.
What is the purpose of the 'low-loss fitting' required by EPA regulations on refrigerant recovery and charging hoses?
Answer: To automatically close and minimize refrigerant release when hoses are disconnected
Low-loss fittings close automatically when disconnected, preventing refrigerant venting to the atmosphere during hose removal as required by EPA Section 608.
A technician uses an electronic leak detector and finds a strong reading near the condenser coil header but no reading at fittings or joints nearby. What should the technician suspect?
Answer: A hairline crack or pinhole in the tubing wall itself, not at a joint
Refrigerant concentrated at a mid-tube location rather than at fittings suggests a crack, corrosion pit, or pinhole in the tubing wall itself, common in older coils.