Core
Pressure Increases
What happens to refrigerant pressure when temperature increases?
An appliance containing 5 pounds or less of refrigerant
What is a Type I appliance?
Poor condenser airflow/heat rejection
What is one major cause of high discharge pressure?
R-123
What is a common Type III refrigerant?
Core, Type I, Type II, Type III
What are the four EPA 608 categories
R-12
What refrigerant was commonly used in older domestic refrigerators?
To prevent refrigerant emissions
What is the purpose of recovering refrigerant from a small appliance?
Micron gauge
What instrument is used to accurately measure deep vacuum?
Leaks can allow air and moisture to enter low-pressure systems
Why are leak tests especially important on low-pressure equipment?
Removing refrigerant and storing it without necessarily processing it
What is refrigerant recovery?
Vapor temperature above its saturation temperature
What is superheat?
Condition, certification, refrigerant compatibility and fill level
What should be checked before using a recovery cylinder?
Nitrogen
What gas is commonly used for leak testing?
Noncondensable gases such as air
What does a purge unit remove?
Liquid refrigerant can cause frostbite/cold burns
Why are gloves important when handling refrigerant?
Carries high-pressure vapor from compressor to condenser
What is the discharge line?
household refrigerator, window AC, small dehumidifier
Moisture, leaks, restrictions, contaminated oil or undersized hoses
What can cause a vacuum pump to pull down slowly?
Increased operating pressure and reduced efficiency
What can excessive air in a low-pressure chiller cause?
Cylinder pressure increases as temperature increases
Why should refrigerant cylinders be kept away from excessive heat (and out of direct sunlight)?
Asphyxiation/Oxygen displacement
What is a major danger of refrigerant entering a small enclosed space?
Liquid refrigerant expands as temperature increases, creating dangerous pressure
Why should recovery cylinders never be filled completely?
It can react violently with oil and create a fire/explosion hazard
Why is Oxygen dangerous when use for pressure testing?
Head pressure and condensing temperature increase
What happens when noncondensables accumulate in a low-pressure chiller?
It violates environmental regulations and can create environmental and safety hazards
Why should refrigerant never be deliberately released?