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
A technician finds acid in the compressor oil during a burnout analysis. After replacing the compressor, which additional service step is MOST critical?
Answer: Install a new filter drier and perform a system flush
Acid from a burnout contaminates the entire system, and a new filter drier with acid-absorption capability, along with flushing, is essential to prevent repeat failure.
What is the recommended method to verify proper refrigerant charge on a fixed-orifice (piston) metering device system?
Answer: Target a superheat of 10–18°F at the evaporator outlet under standard conditions
Fixed-orifice systems are charged using superheat method, typically targeting 10–18°F at the evaporator outlet to ensure proper refrigerant feed without flooding.
During a service call, a technician confirms low refrigerant charge. Before adding refrigerant, the technician should:
Answer: Locate and repair the leak first
EPA regulations and good practice require finding and repairing leaks before recharging, as simply topping off a leaking system wastes refrigerant and is non-compliant.
A condenser fan motor runs but the blade is not turning. The MOST likely cause is:
Answer: Broken or loose fan blade set screw
If the motor shaft spins but the blade does not move, the fan blade's set screw or retaining hardware has failed, disconnecting the blade from the shaft.
What is the purpose of the suction line accumulator in an air conditioning system?
Answer: To prevent liquid refrigerant from entering the compressor
The accumulator is located on the suction line and holds excess liquid refrigerant, allowing only vapor to enter the compressor and preventing liquid slugging.
A technician measures 240V at the contactor line side terminals but 0V at the load side terminals when the thermostat calls for cooling. This indicates:
Answer: The contactor coil is not being energized or the contactor is faulty
Voltage present on the line side but absent on the load side means the contactor has not closed, pointing to no control voltage at the coil or a failed contactor.
What is the correct action if a technician suspects moisture contamination inside an air conditioning system?
Answer: Recover refrigerant, replace the filter drier, evacuate deeply, then recharge
Moisture must be removed by replacing the filter drier (which absorbs moisture), then performing a deep vacuum evacuation to below 500 microns before recharging.