Car Air Conditioning Repair Flashcards
7 cards from real Air Conditioning Repair practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Car Air Conditioning Repair flashcards as text
What tool is required to safely recover refrigerant from a car AC system before opening it for repair?
Answer: Refrigerant recovery machine
A refrigerant recovery machine captures refrigerant from the system into a certified recovery cylinder, which is legally required before any AC repair that opens the system.
A car's AC blows cold for 10 minutes then gradually turns warm. What is the most likely cause?
Answer: Icing of the evaporator due to low refrigerant
Low refrigerant causes the evaporator coil to drop below freezing, forming ice that blocks airflow; once the ice melts, cooling briefly returns before icing again.
Which component in a car AC system is responsible for removing moisture from the refrigerant?
Answer: Receiver-drier
The receiver-drier contains desiccant material that absorbs moisture from the refrigerant, preventing ice formation and acid contamination.
What does a high-side pressure reading significantly above normal indicate during AC diagnosis?
Answer: Restricted or failing condenser
Abnormally high discharge-side pressure typically points to poor condenser airflow, a dirty condenser coil, or a failing condenser fan that prevents heat rejection.
When leak-testing a car AC system after repair, which method is preferred for locating small leaks?
Answer: Inject UV dye then use a UV lamp
UV dye injection followed by UV lamp inspection is a precise, widely accepted method that visually highlights even small leak points without risk of contaminating a dry system.
A technician finds the AC compressor cycling on and off rapidly (short cycling). What is the most likely cause?
Answer: Low refrigerant triggering the low-pressure cutoff switch
Low refrigerant causes system pressure to drop below the low-pressure switch threshold, cutting the compressor off; it restarts once pressure rises slightly, causing rapid cycling.
What is the purpose of pulling a vacuum (evacuation) on a car AC system before recharging?
Answer: To remove air and moisture from the system
Evacuation lowers system pressure below atmospheric, boiling off any moisture and purging non-condensable air that would raise head pressure and reduce efficiency.