Master Compressor Troubleshooting: Enhance Your HVAC Skills

Question 1

Which of the following symptoms is most likely caused by a faulty start capacitor in a compressor?

Accepted Answer

Slow or hard starting

Answer

Overheating

Answer

Noisy operation

Answer

Reduced cooling capacity

Question 2

What is the primary function of the overload protector in a compressor?

Accepted Answer

To prevent overheating and damage to the compressor motor

Answer

To regulate the flow of refrigerant

Answer

To improve compressor efficiency

Answer

To reduce noise levels

Question 3

What is the recommended method for evacuating a refrigeration system before recharging it with refrigerant?

Accepted Answer

Using a vacuum pump

Answer

Purging with nitrogen

Answer

Opening the system to the atmosphere

Answer

Using an air compressor

Question 4

Which of the following tools is essential for accurately measuring refrigerant pressure in a refrigeration system?

Accepted Answer

Manometer

Answer

Multimeter

Answer

Thermometer

Answer

Ammeter

Question 5

What is the primary function of the condenser in a refrigeration system?

Accepted Answer

To remove heat from the refrigerant and release it into the surroundings

Answer

To expand the refrigerant from a liquid to a gas

Answer

To compress the refrigerant vapor into a liquid

Answer

To evaporate the refrigerant liquid into a gas

Question 6

Which of the following system components is responsible for controlling the flow of refrigerant into the evaporator?

Accepted Answer

Expansion valve

Answer

Condenser

Answer

Compressor

Answer

Evaporator

Question 7

What is the purpose of adding oil to a refrigeration system?

Accepted Answer

To lubricate moving parts such as the compressor

Answer

To improve heat transfer within the system

Answer

To prevent corrosion of metal components

Answer

To increase the flow rate of refrigerant

Question 8

In troubleshooting a compressor with low compression, which step should be the first priority?

Accepted Answer

Check the refrigerant charge

Answer

Replace the compressor

Answer

Clean the condenser coils

Question 9

When troubleshooting electrical faults in a compressor, why is it crucial to ensure proper grounding and insulation testing?

Accepted Answer

To prevent electrical shock and ensure the safety of individuals working on the compressor

Answer

To enhance the compressor's energy efficiency

Answer

To simplify the disassembly of the compressor for maintenance or repair tasks

Answer

To adhere to industry regulations and standards

Question 10

What is a common symptom of a faulty compressor start capacitor?

Accepted Answer

The compressor hums but does not start

Answer

The compressor overheats

Answer

The compressor vibrates excessively

Answer

The compressor draws high current

Question 11

What is the primary purpose of the overload protector in a compressor?

Accepted Answer

To prevent compressor damage due to overheating

Answer

To improve compressor efficiency

Answer

To reduce compressor noise

Answer

To maintain refrigerant pressure

Question 12

Which tool is the most appropriate for testing the resistance of a compressor coil?

Accepted Answer

Digital multimeter

Answer

Thermometer

Answer

Pressure gauge

Answer

Amp clamp

Question 13

What is the primary function of the suction accumulator in a refrigeration system?

Accepted Answer

To separate liquid from gas refrigerant

Answer

To store liquid refrigerant

Answer

To regulate refrigerant flow

Answer

To prevent oil migration

Question 14

What can happen if a compressor bearing fails, and how can we prevent this?

Accepted Answer

Loud noise, strong vibrations, and the compressor might seize up.

Answer

Bearing failure doesn't really affect how the compressor works.

Answer

Bearing failure only causes the compressor to overheat.

Answer

Bearing failure only happens in rotary compressors.

Question 15

An air conditioner is blowing warm air instead of cold. Which of these could be the problem?

Accepted Answer

Low refrigerant

Accepted Answer

Dirty condenser coil

Accepted Answer

Broken capacitor

Answer

Air conditioner is too big

Question 16

What is the primary function of a compressor in an HVAC system?

Accepted Answer

To circulate the refrigerant

Answer

To cool the air

Answer

To condense the refrigerant

Answer

To evaporate the refrigerant

Question 17

Which of the following actions should be taken if the compressor is making excessive noise?

Accepted Answer

Check for loose bolts

Answer

Ignore it

Answer

Replace the compressor

Answer

Increase the refrigerant level

Question 18

What is the purpose of a capacitor in a compressor?

Accepted Answer

To start the motor

Answer

To regulate the refrigerant flow

Answer

To protect the motor from overloads

Answer

To improve the system's efficiency

Question 19

Which of the following is NOT a potential cause of low refrigerant pressure?

Accepted Answer

Overcharge of refrigerant

Answer

Leak in the system

Answer

Faulty expansion valve

Answer

Blocked evaporator coils

Question 20

What is the primary function of the suction accumulator in a refrigeration system?

Accepted Answer

To prevent liquid refrigerant from entering the compressor

Answer

To store excess refrigerant

Answer

To filter out contaminants

Answer

To regulate the flow of refrigerant

Question 21

What is the most frequent reason for a compressor to overheat?

Accepted Answer

Insufficient condenser airflow

Answer

Clogged refrigerant filter

Answer

Low refrigerant level

Answer

Faulty thermostat

Question 22

Which of the following is the correct sequence of steps when replacing a failed compressor?

Accepted Answer

Evacuate the system, remove refrigerant, disconnect wiring, replace compressor, recharge system

Answer

Evacuate the system, disconnect wiring, replace compressor, recharge system, remove refrigerant

Answer

Disconnect wiring, replace compressor, evacuate the system, recharge system, remove refrigerant

Answer

Replace compressor, disconnect wiring, evacuate the system, remove refrigerant, recharge system

Question 23

Which of the following is NOT a type of compressor valve?

Accepted Answer

Rotary valve

Answer

Check valve

Answer

Reed valve

Answer

Diaphragm valve

Question 24

What is the purpose of the compressor contactor?

Accepted Answer

To control the power supply to the compressor

Answer

To protect the compressor from overloads

Answer

To regulate the compressor's speed

Answer

To act as a safety switch

Question 25

Which of the following tools is used to measure the compressor's current consumption?

Accepted Answer

Amp clamp

Answer

Voltmeter

Answer

Ohmmeter

Answer

Capacitance meter

Question 26

In a pressure-enthalpy (p-h) diagram for a refrigeration cycle, which process represents the constant pressure heat absorption in the evaporator?

Accepted Answer

Constant pressure heat absorption

Answer

Adiabatic compression

Answer

Adiabatic expansion

Answer

Constant volume heat rejection

Question 27

Which of these actions is **harmful** to a refrigeration compressor?

Accepted Answer

Overloading the compressor

Answer

Regular oil changes

Answer

Replacing air filters

Answer

Monitoring refrigerant levels

Question 28

What is the main function of the suction line filter drier in an HVAC system?

Accepted Answer

To filter out impurities like moisture and particles from the refrigerant

Answer

To control refrigerant pressure

Answer

To hold extra refrigerant

Answer

To provide lubrication for the compressor

Question 29

What is the primary function of the capacitor in a compressor?

Accepted Answer

Provides the initial power surge to start the motor and maintain its operation

Answer

Acts as a voltage regulator

Answer

Stores electrical energy

Answer

Filters out contaminants

Question 30

Which tool is used to measure refrigerant pressure and temperature?

Accepted Answer

Manifold gauge

Answer

Megohmmeter

Answer

Voltmeter

Answer

Psychrometer

Question 31

What is the recommended first step when troubleshooting a compressor?

Accepted Answer

Inspect the power supply and wiring

Answer

Check the refrigerant pressure

Answer

Inspect the compressor for leaks

Answer

Replace the capacitor

Question 32

What is the purpose of a hard-start kit?

Accepted Answer

Provides additional power to assist in starting a compressor with low starting torque, especially in low-temperature conditions

Answer

Prevents compressor overheating

Answer

Reduces noise from the compressor

Answer

Improves compressor efficiency

Question 33

What is the primary role of the compressor in a refrigeration cycle?

Accepted Answer

Compresses and circulates the refrigerant throughout the system

Answer

Condenses the refrigerant

Answer

Expands the refrigerant

Answer

Cools the air in the conditioned space

Question 34

Which symptom is indicative of a locked rotor in a compressor?

Accepted Answer

Motor hums but does not rotate

Answer

Overheating

Answer

Refrigerant leaks

Answer

Loud noises

Question 35

What is the acceptable amperage range for a properly functioning compressor?

Accepted Answer

80-120% of the rated full-load amperage (FLA)

Answer

50-70% of the rated FLA

Answer

Less than 50% of the rated FLA

Answer

120-150% of the rated FLA

Question 36

Which of the following is NOT a common cause of compressor failure in refrigeration systems?

Accepted Answer

High voltage

Answer

Insufficient lubrication

Answer

Contaminated refrigerant

Answer

Overheating

Question 37

What is the primary function of the compressor in a refrigeration cycle?

Accepted Answer

Circulate refrigerant and increase its pressure

Answer

Condense refrigerant and release heat

Answer

Filter and clean refrigerant

Answer

Expand refrigerant and absorb heat

Question 38

Which type of refrigerant is commonly used in residential air conditioning systems in the United States?

Accepted Answer

R-410A

Answer

R-134a

Answer

R-22

Answer

R-12

Question 39

What is the main purpose of a capacitor in a compressor circuit?

Accepted Answer

To provide a boost of electrical energy, improving starting torque and efficiency

Answer

To regulate compressor speed

Answer

To protect the compressor from overloads

Question 40

Which of the following symptoms is associated with a faulty start capacitor in a compressor?

Accepted Answer

Compressor fails to start or hums

Answer

Refrigerant leaks

Answer

Compressor runs continuously

Question 41

When troubleshooting a compressor, what is the recommended method to check the continuity of a compressor winding?

Accepted Answer

Use a multimeter to measure resistance between terminals

Answer

Check for voltage at the terminals

Answer

Apply power and observe operation

Question 42

Which tool is primarily used to evacuate air and moisture from a refrigeration system before charging refrigerant?

Accepted Answer

Vacuum pump

Answer

Pressure gauge

Answer

Refrigerant leak detector

Question 43

What is the main purpose of a sight glass in a refrigeration system?

Accepted Answer

To observe refrigerant flow and detect the presence of any air or moisture

Answer

To determine the appropriate refrigerant charge

Answer

To indicate refrigerant pressure

Question 44

Which of the following symptoms may indicate a faulty or failing compressor capacitor in a refrigeration system?

Accepted Answer

The compressor produces a humming sound but does not start

Answer

Excessive compressor vibration

Answer

Unusually high suction pressure

Answer

Unusually low discharge pressure

Question 45

What is the primary purpose of the overload protector in a compressor?

Accepted Answer

To safeguard the compressor from potential damage caused by excessive electrical current or overloads

Answer

To optimize compressor efficiency by adjusting refrigerant flow

Answer

To monitor and regulate compressor temperature

Question 46

What is the primary role of a suction accumulator in a refrigeration system?

Accepted Answer

To prevent liquid refrigerant from entering the compressor, potentially causing damage

Answer

To store excess refrigerant when the system is not in operation

Answer

To regulate and maintain refrigerant pressure within the system

Question 47

Which of the following is a common symptom associated with worn or failing compressor bearings?

Accepted Answer

Excessive noise and vibration during compressor operation

Answer

Rapid and frequent compressor cycling

Answer

Reduced compressor efficiency

Answer

Unusually high refrigerant pressure

Question 48

What is the main purpose of a compressor's discharge valve?

Accepted Answer

Control refrigerant flow to the condenser

Answer

Prevent refrigerant leakage

Answer

Lubricate moving parts

Answer

Cool the compressor motor

Question 49

What is the primary function of a compressor's oil pump?

Accepted Answer

Lubricate moving parts and maintain oil pressure

Answer

Control refrigerant flow

Answer

Cool the compressor motor

Answer

Prevent refrigerant leakage

Question 50

Which of the following instruments is typically used to measure compressor amperage?

Accepted Answer

Clamp-on ammeter

Answer

Thermometer

Answer

Pressure gauge

Answer

Multimeter

Question 51

What is the most prevalent cause of a seized compressor?

Accepted Answer

Lack of lubrication

Answer

Overheating

Answer

Excessive refrigerant charge

Answer

Faulty wiring

Question 52

Which of the following can result from a faulty compressor capacitor?

Accepted Answer

Reduced compressor efficiency and overheating

Answer

Improved cooling performance

Answer

Lower starting torque

Answer

Increased refrigerant flow

Question 53

What is the main purpose of a compressor's suction line filter?

Accepted Answer

Remove contaminants from the refrigerant

Answer

Lubricate moving parts

Answer

Control refrigerant flow

Question 54

Which of the following symptoms is associated with a faulty compressor contactor?

Accepted Answer

Intermittent compressor operation

Answer

Low suction pressure

Answer

Excessive noise

Answer

High compressor amperage

Question 55

What is the main function of a compressor's head pressure control?

Accepted Answer

Maintain optimal discharge pressure and prevent overheating

Answer

Control refrigerant flow

Answer

Lubricate moving parts