Refrigeration Quiz
Questions: 16 · 10 minutes
1. Moisture remains inside a refrigeration circuit after service. What problem can occur when it reaches a cold metering device?
It permanently increases the refrigerant's cooling capacity
It can freeze and create an intermittent refrigerant restriction
It raises airflow resistance across the condenser fins
It eliminates the need for system evacuation
2. Why must a pressure-temperature chart or gauge scale match the refrigerant in the system?
Each refrigerant requires a unique pipe diameter at every pressure
Gauge pressure is meaningful only when the compressor is off
Different refrigerants have different saturation temperatures at the same pressure
All refrigerants share a saturation curve but use different safety colors
3. What is the compressor's main role in the refrigeration cycle?
To reduce the liquid refrigerant's pressure before the evaporator
To turn high-pressure liquid directly into low-pressure vapor
To remove moisture from the conditioned air
To raise the vapor's pressure and maintain refrigerant circulation
4. A suction line passes through a hot equipment room with damaged insulation. Assuming other conditions remain similar, what is the most likely result at the compressor inlet?
The vapor condenses because the surrounding air is warmer
The vapor gains sensible heat, which can increase measured superheat
The refrigerant pressure automatically rises to discharge pressure
The liquid subcooling increases because insulation is missing
5. What is the evaporator's primary function in a vapor-compression refrigeration system?
To absorb heat as low-pressure refrigerant boils
To reject heat as high-pressure vapor condenses
To raise refrigerant pressure by compressing liquid
To store refrigerant until the thermostat calls
6. Two refrigeration systems provide the same cooling capacity under the same conditions. System A uses less electrical power than System B. What follows from this comparison?
System A must have a larger refrigerant charge
System A has a higher coefficient of performance under those conditions
System B has a lower condensing temperature in every case
System B removes more latent heat because it draws more power
7. Which measurement describes liquid refrigerant cooled below its saturation temperature at the measured pressure?
Liquid subcooling
Evaporator temperature difference
Suction superheat
Compression ratio
8. A return-air filter is completely blocked, and airflow across the evaporator has become weak. What is the most likely immediate operating effect?
Higher refrigerant flow because the blocked filter raises liquid pressure
Increased heat load on the evaporator, producing high suction pressure
Faster condensation because less air reaches the indoor coil
Reduced heat transfer to the evaporator, potentially causing an unusually cold or iced coil
9. The evaporator is cold and the compressor is running, but the evaporator fan has stopped. Why will the conditioned space receive little cooling?
The stationary fan causes refrigerant to bypass the metering device
Too little room air is moving across the evaporator to transfer and distribute heat effectively
The condenser can reject heat only while the evaporator fan rotates
The stopped fan immediately converts the evaporator into a condenser
10. A technician measures suction pressure, converts it to saturation temperature for the correct refrigerant, and compares that value with suction-line temperature. What is being calculated?
Suction-vapor superheat
Liquid-line subcooling
Condenser approach temperature
Compressor pressure ratio
11. An air-cooled condenser is heavily clogged with debris while its fan continues to run. What condition is most likely?
Lower condensing pressure because the refrigerant stays in the coil longer
Higher indoor airflow because the compressor works harder
Lower evaporator superheat because condenser airflow controls the expansion valve directly
Higher condensing pressure because heat rejection is restricted
12. What normally happens to refrigerant in the condenser?
It absorbs heat and changes from liquid to vapor
It expands while remaining at constant pressure
It rejects heat and changes from vapor toward liquid
It is compressed into a higher-temperature vapor
13. Non-condensable gas has entered the high side of an otherwise operating refrigeration system. What behavior is it most likely to cause?
A lower total high-side pressure because the gas absorbs refrigerant vapor
Complete evaporation of compressor oil at normal temperatures
An elevated head pressure and poorer condenser performance
An automatic increase in evaporator airflow
14. Warm, humid air is cooled below its dew point as it crosses an evaporator. Which description best explains the cooling performed?
Sensible heat is removed as air cools, and latent heat is removed as moisture condenses
Only sensible heat is removed because condensate carries no energy
Heat is added to the air while moisture condenses
Only latent heat is removed because air temperature cannot change below the dew point
15. What is the central function of a refrigeration system's metering device?
To raise suction vapor pressure before compression
To separate oil from discharge vapor
To regulate refrigerant flow and create a pressure drop
To remove heat from the refrigerant before condensation
16. Before opening a system that may contain refrigerant, what is the responsible procedure?
Release the charge outdoors so pressure cannot build indoors
Run the compressor until the system reaches a complete vacuum
Mix the refrigerant with air to reduce its concentration
Recover it with suitable equipment according to applicable procedures and regulations