System Installation and Brazing 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 Brazing flashcards as text
When installing a split-system condenser, the minimum clearance from the unit to any wall or obstruction on the discharge (top) side should be:
Answer: 24 inches
Most manufacturers specify at least 24 inches of clearance above the discharge grille to allow proper airflow and prevent hot air recirculation.
What flux is most commonly used when brazing copper-to-copper refrigerant joints?
Answer: No flux is needed for copper-to-copper joints
Copper-to-copper joints with high-silver alloy brazing rod do not require flux because the alloy flows well on clean copper without it; flux can leave residues.
The liquid line in a residential AC system is typically NOT insulated because:
Answer: The liquid refrigerant temperature is near ambient and condensation is not a concern
The liquid line carries subcooled refrigerant near ambient temperature, so condensation does not form and insulation provides negligible benefit.
When pulling a vacuum on a newly installed residential AC system, the system should reach and hold:
Answer: 500 microns or below with no rise above 1,000 microns after isolation
Industry standard requires the system to reach 500 microns or below; after isolating the vacuum pump, the reading should remain stable and not rise above 1,000 microns, indicating a dry, leak-free system.
A 'P-trap' installed in a condensate drain line serves to:
Answer: Maintain a water seal to prevent sewer gases from entering the air handler
The P-trap's water seal prevents odorous or harmful gases from the drain system from being drawn into the air handler by the unit's negative pressure.
When sizing the refrigerant line set for a residential split system, the technician should consult:
Answer: The equipment manufacturer's installation manual for approved line sizes and lengths
Manufacturers specify maximum and minimum line lengths and required line sizes to maintain proper oil return and refrigerant charge for their equipment.
Which of the following best describes 'swaging' in refrigerant line work?
Answer: Expanding the end of a tube so another tube of the same diameter can be inserted for brazing
Swaging expands the end of one tube to accept another tube of the same diameter, creating a socket joint suitable for brazing.