Refrigeration Flashcards
7 cards from real HVAC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Refrigeration flashcards as text
What is the purpose of pulling a vacuum (evacuating) a refrigeration system before charging?
Answer: Remove air, nitrogen, and moisture from the system
Evacuation removes air, non-condensable gases, and moisture from the system to prevent contamination, acid formation, and ice blockages.
Which component in a refrigeration system separates refrigerant vapor from liquid to ensure only vapor enters the compressor in a flooded evaporator system?
Answer: Suction accumulator
A suction accumulator is installed in the suction line to separate and hold any liquid refrigerant, allowing only vapor to pass to the compressor.
What does a sight glass/moisture indicator show when the refrigerant system is properly charged and dry?
Answer: A clear (bubble-free) window with a green indicator dot
A properly charged, dry system shows a clear sight glass with no bubbles and a green moisture indicator dot; bubbles indicate low charge and yellow indicates moisture.
In a heat pump system, which component reverses the refrigerant flow direction to switch between heating and cooling modes?
Answer: Four-way reversing valve
A four-way reversing valve redirects refrigerant flow so the outdoor coil becomes the evaporator in cooling mode and the condenser in heating mode.
What is the minimum vacuum level (in microns) generally considered acceptable before charging a refrigeration system?
Answer: 500 microns
The industry standard is to pull a vacuum to 500 microns or lower before charging, ensuring adequate moisture removal and leak verification.
What is the Ozone Depletion Potential (ODP) of R-410A refrigerant?
Answer: 0 (zero)
R-410A has an ODP of zero because it contains no chlorine atoms that could destroy stratospheric ozone, unlike older refrigerants such as R-22.
When adding refrigerant to a system that uses a blended refrigerant (such as R-410A), how must it be charged?
Answer: As a liquid from the refrigerant cylinder
Blended refrigerants like R-410A must be charged as a liquid to prevent fractionation, where different components evaporate at different rates, changing the blend composition.