System Installation and Maintenance Flashcards
7 cards from real 313D practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 System Installation and Maintenance flashcards as text
A technician installs a new residential heat pump and notices the reversing valve solenoid is energized in cooling mode. This indicates the system uses which wiring configuration?
Answer: O-wire configuration (energized in cooling)
Most heat pumps use the O-wire configuration, where the reversing valve solenoid is energized in cooling mode; Trane/American Standard systems use the B-wire (energized in heating) configuration.
When brazing copper refrigerant lines, what gas should be flowed through the tubing during the brazing process and why?
Answer: Nitrogen, to prevent oxidation scale inside the tubing
Dry nitrogen is flowed through copper tubing during brazing to prevent the formation of copper oxide scale inside the lines, which would contaminate the refrigerant system.
A residential AC system has been running for 10 years. The technician notices the suction line is not sweating and feels warm. What condition does this MOST likely indicate?
Answer: The system has a refrigerant undercharge or restriction
A warm, dry suction line instead of the expected cool, sweating suction line typically indicates a refrigerant undercharge or a restriction upstream of the evaporator coil.
When sizing a condensate pump for a residential air handler installed in a basement without gravity drain access, which factor is MOST important?
Answer: The pump's lift capacity relative to the required discharge height
The condensate pump must have sufficient lift capacity to pump condensate to the required discharge height (vertical rise) where it can drain by gravity.
A technician is performing a leak check on a newly installed system using an electronic leak detector. Where should they check FIRST for common installation-related leaks?
Answer: Brazed joints, flare connections, and Schrader valve cores
Brazed joints, flare connections, and Schrader valve cores are the most common locations for refrigerant leaks after a new installation and should be the first points checked.
What does a superheat measurement of 0°F at the outlet of the evaporator coil indicate about system operation?
Answer: Liquid refrigerant is flooding back to the compressor, indicating overcharge or a failed metering device
Zero superheat means all refrigerant has not boiled off in the evaporator, meaning liquid refrigerant is reaching the compressor outlet, which can damage the compressor.
When completing a new residential AC installation, what documentation should the technician provide to the homeowner?
Answer: Installation documentation, warranty registration information, and basic operational and maintenance instructions
Technicians should provide homeowners with installation records, warranty registration details, and maintenance guidance to protect the equipment warranty and ensure proper owner care.