Service 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 Service flashcards as text
When performing a refrigerant recovery, the technician should recover the refrigerant until the system pressure reaches:
Answer: 0 psig or as low as possible
EPA regulations require recovering refrigerant to 0 psig or as low as the recovery machine can achieve to minimize emissions.
A technician notices that the evaporator coil is icing up during operation. Which service step should be performed FIRST?
Answer: Check airflow across the evaporator
Restricted airflow is the most common cause of evaporator icing, and checking it first eliminates the simplest root cause before invasive repairs.
What is the purpose of performing a standing pressure test on a system after repair?
Answer: To verify no leaks exist before charging with refrigerant
A standing pressure test uses dry nitrogen to verify system integrity and confirm no leaks are present before introducing refrigerant.
Which oil is required for use in systems containing R-410A refrigerant?
Answer: POE (polyolester) oil
R-410A systems require POE (polyolester) oil because it is miscible with HFC refrigerants, ensuring proper lubrication throughout the system.
During a service call, a technician measures suction pressure lower than normal and discharge pressure lower than normal. This most likely indicates:
Answer: Low refrigerant charge
Both suction and discharge pressures below normal simultaneously is a classic indicator of an undercharged (low refrigerant) system.
Before replacing a compressor, a technician should always:
Answer: Perform a system flush to remove contaminants
Flushing removes acid, moisture, and debris from a failed compressor before installing a new one, preventing premature failure of the replacement.
A technician is checking subcooling on a fixed-orifice system. Where should subcooling be measured?
Answer: At the liquid line service valve near the condenser outlet
Subcooling is measured at the liquid line leaving the condenser, comparing the actual temperature to the saturation temperature at that pressure.