1. Q: What is the primary function of an air conditioning system?
ANSWER To control temperature, humidity, air movement, and air quality
within a conditioned space.
2. Q: What are the four main components of a basic refrigeration cycle?
ANSWER Compressor, condenser, expansion device, and evaporator.
3. Q: What is the standard comfort temperature range for most occupied
spaces? ANSWER 68°F to 75°F, depending on season and humidity levels.
4. Q: What does HVAC stand for? ANSWER Heating, Ventilation, and Air
Conditioning.
5. Q: What is relative humidity? ANSWER The amount of moisture in the air
compared to the maximum amount the air can hold at a given temperature,
expressed as a percentage.
6. Q: What is sensible heat? ANSWER Heat that causes a change in
temperature but not a change in state of a substance.
7. Q: What is latent heat? ANSWER Heat that causes a change in state of a
substance without changing its temperature.
8. Q: What is a ton of refrigeration? ANSWER The amount of cooling
required to melt one ton (2,000 pounds) of ice in 24 hours, equal to 12,000 BTU
per hour.
9. Q: What does BTU stand for? ANSWER British Thermal Unit, the amount
of heat required to raise one pound of water one degree Fahrenheit.
,10. Q: What is superheat? ANSWER The temperature of refrigerant vapor
above its saturation temperature at a given pressure.
11. Q: What is subcooling? ANSWER The temperature of liquid refrigerant
below its saturation temperature at a given pressure.
12. Q: What is the purpose of superheat in an air conditioning system?
ANSWER To ensure only vapor enters the compressor, preventing liquid
slugging and protecting the compressor.
13. Q: What is the ideal relative humidity range for comfort? ANSWER
30% to 60% relative humidity.
14. Q: What is the dew point? ANSWER The temperature at which air
becomes saturated and water vapor begins to condense.
15. Q: What is static pressure in an HVAC system? ANSWER The pressure
exerted by air at rest in a duct system.
16. Q: What is velocity pressure? ANSWER The pressure created by air in
motion.
17. Q: What is total pressure in ductwork? ANSWER The sum of static
pressure and velocity pressure.
18. Q: What is CFM? ANSWER Cubic Feet per Minute, a measurement of air
volume flow rate.
19. Q: What is the standard air flow rate per ton of cooling? ANSWER
Approximately 400 CFM per ton.
20. Q: What is the purpose of an air filter in an HVAC system? ANSWER
To remove particulates, dust, and contaminants from the air stream to protect
equipment and improve indoor air quality.
21. Q: What does MERV stand for? ANSWER Minimum Efficiency
Reporting Value, a rating system for air filters.
22. Q: What is the typical temperature drop across an evaporator coil?
ANSWER 15°F to 20°F.
23. Q: What causes frost to form on an evaporator coil? ANSWER
Insufficient air flow, low refrigerant charge, dirty coils, or outdoor temperature
below 60°F.
24. Q: What is a heat pump? ANSWER A refrigeration system capable of
reversing its cycle to provide both heating and cooling.
, 25. Q: What is coefficient of performance (COP)? ANSWER The ratio of
useful heating or cooling provided to work required, measuring efficiency.
26. Q: What is SEER? ANSWER Seasonal Energy Efficiency Ratio,
measuring cooling efficiency over an entire season.
27. Q: What is EER? ANSWER Energy Efficiency Ratio, measuring cooling
efficiency at a specific operating point.
28. Q: What is psychrometrics? ANSWER The study of the properties of air-
water vapor mixtures.
29. Q: What is enthalpy? ANSWER The total heat content of air, including
both sensible and latent heat.
30. Q: What is wet bulb temperature? ANSWER The temperature indicated
by a thermometer covered with a water-saturated wick over which air passes.
31. Q: What is dry bulb temperature? ANSWER The ambient air
temperature measured by a standard thermometer.
32. Q: What causes high head pressure in a condensing unit? ANSWER
Dirty condenser coil, insufficient air flow, overcharge of refrigerant, or high
ambient temperature.
33. Q: What causes low suction pressure? ANSWER Restricted air flow,
dirty filters, low refrigerant charge, or restricted metering device.
34. Q: What is the purpose of a sight glass? ANSWER To visually observe
refrigerant flow and check for bubbles indicating low charge or flash gas.
35. Q: What is the standard voltage for residential air conditioning
equipment? ANSWER 208-230 volts single phase, or 208/230 volts three
phase for larger units.
36. Q: What is the purpose of a crankcase heater? ANSWER To prevent
refrigerant from migrating to and condensing in the compressor crankcase
during off cycles.
37. Q: What is short cycling? ANSWER When an air conditioning unit turns
on and off too frequently, typically cycling in less than 5-10 minutes.
38. Q: What causes short cycling? ANSWER Oversized equipment, dirty
filters, refrigerant problems, thermostat issues, or frozen evaporator coils.
ANSWER To control temperature, humidity, air movement, and air quality
within a conditioned space.
2. Q: What are the four main components of a basic refrigeration cycle?
ANSWER Compressor, condenser, expansion device, and evaporator.
3. Q: What is the standard comfort temperature range for most occupied
spaces? ANSWER 68°F to 75°F, depending on season and humidity levels.
4. Q: What does HVAC stand for? ANSWER Heating, Ventilation, and Air
Conditioning.
5. Q: What is relative humidity? ANSWER The amount of moisture in the air
compared to the maximum amount the air can hold at a given temperature,
expressed as a percentage.
6. Q: What is sensible heat? ANSWER Heat that causes a change in
temperature but not a change in state of a substance.
7. Q: What is latent heat? ANSWER Heat that causes a change in state of a
substance without changing its temperature.
8. Q: What is a ton of refrigeration? ANSWER The amount of cooling
required to melt one ton (2,000 pounds) of ice in 24 hours, equal to 12,000 BTU
per hour.
9. Q: What does BTU stand for? ANSWER British Thermal Unit, the amount
of heat required to raise one pound of water one degree Fahrenheit.
,10. Q: What is superheat? ANSWER The temperature of refrigerant vapor
above its saturation temperature at a given pressure.
11. Q: What is subcooling? ANSWER The temperature of liquid refrigerant
below its saturation temperature at a given pressure.
12. Q: What is the purpose of superheat in an air conditioning system?
ANSWER To ensure only vapor enters the compressor, preventing liquid
slugging and protecting the compressor.
13. Q: What is the ideal relative humidity range for comfort? ANSWER
30% to 60% relative humidity.
14. Q: What is the dew point? ANSWER The temperature at which air
becomes saturated and water vapor begins to condense.
15. Q: What is static pressure in an HVAC system? ANSWER The pressure
exerted by air at rest in a duct system.
16. Q: What is velocity pressure? ANSWER The pressure created by air in
motion.
17. Q: What is total pressure in ductwork? ANSWER The sum of static
pressure and velocity pressure.
18. Q: What is CFM? ANSWER Cubic Feet per Minute, a measurement of air
volume flow rate.
19. Q: What is the standard air flow rate per ton of cooling? ANSWER
Approximately 400 CFM per ton.
20. Q: What is the purpose of an air filter in an HVAC system? ANSWER
To remove particulates, dust, and contaminants from the air stream to protect
equipment and improve indoor air quality.
21. Q: What does MERV stand for? ANSWER Minimum Efficiency
Reporting Value, a rating system for air filters.
22. Q: What is the typical temperature drop across an evaporator coil?
ANSWER 15°F to 20°F.
23. Q: What causes frost to form on an evaporator coil? ANSWER
Insufficient air flow, low refrigerant charge, dirty coils, or outdoor temperature
below 60°F.
24. Q: What is a heat pump? ANSWER A refrigeration system capable of
reversing its cycle to provide both heating and cooling.
, 25. Q: What is coefficient of performance (COP)? ANSWER The ratio of
useful heating or cooling provided to work required, measuring efficiency.
26. Q: What is SEER? ANSWER Seasonal Energy Efficiency Ratio,
measuring cooling efficiency over an entire season.
27. Q: What is EER? ANSWER Energy Efficiency Ratio, measuring cooling
efficiency at a specific operating point.
28. Q: What is psychrometrics? ANSWER The study of the properties of air-
water vapor mixtures.
29. Q: What is enthalpy? ANSWER The total heat content of air, including
both sensible and latent heat.
30. Q: What is wet bulb temperature? ANSWER The temperature indicated
by a thermometer covered with a water-saturated wick over which air passes.
31. Q: What is dry bulb temperature? ANSWER The ambient air
temperature measured by a standard thermometer.
32. Q: What causes high head pressure in a condensing unit? ANSWER
Dirty condenser coil, insufficient air flow, overcharge of refrigerant, or high
ambient temperature.
33. Q: What causes low suction pressure? ANSWER Restricted air flow,
dirty filters, low refrigerant charge, or restricted metering device.
34. Q: What is the purpose of a sight glass? ANSWER To visually observe
refrigerant flow and check for bubbles indicating low charge or flash gas.
35. Q: What is the standard voltage for residential air conditioning
equipment? ANSWER 208-230 volts single phase, or 208/230 volts three
phase for larger units.
36. Q: What is the purpose of a crankcase heater? ANSWER To prevent
refrigerant from migrating to and condensing in the compressor crankcase
during off cycles.
37. Q: What is short cycling? ANSWER When an air conditioning unit turns
on and off too frequently, typically cycling in less than 5-10 minutes.
38. Q: What causes short cycling? ANSWER Oversized equipment, dirty
filters, refrigerant problems, thermostat issues, or frozen evaporator coils.
