HVAC: EPA 608 Certification Study Guide |
100% Correct Answers | Verified | Latest
2024 Version
Are there drop-in replacements for R-12 systems? Why or why not? - ✔✔No because the new
refrigerants are incompatible with the oils and lubricants used in R-12 systems.
What type of oil is used in R-134a and what oils will it mix with? - ✔✔Ester based oils and they do not
mix with other oils
What type of lubricant is used with HCFCs? - ✔✔Alkylbenzene lubricant
What is difference b/w ternary blend a azeotropic blend? - ✔✔Ternary blends are three-part mixtures
whereas azeotropic blends are blends of two or more compounds that act like a single compound.
What is the trait of a hygroscopic lubricant? - ✔✔It absorbs (takes on) moisture
What is temperature glide and what type of blend won't have it? - ✔✔Temp. blend is the difference
between the dew point and the bubble point
Dew Point - ✔✔Occurs when saturation temp in evaporator causes refrigerant to change from liquid to
vapor
Bubble Point - ✔✔Occurs when saturation temp in condenser changes refrigerant from vapor to liquid
Will the gases in a ternary blend leak at the same rate? Why or why not? - ✔✔No because different
refrigerants in blend have different vapor pressures, causing them to leak at uneven rates
Refrigeration Process - ✔✔transfer of heat from one place to another
, Evaporator - ✔✔Absorbs heat into system from space to be cooled. Absorption of heat causes
refrigerant to boil. Upon leaving, refrigerant changed to low pressure, low temperature vapor
Compressor - ✔✔Takes low pressure, low temp vapor and changes it to a high-temp, high-pressure,
superheated vapor and delivers it to the condenser
Condenser - ✔✔Rejects heat from system and changes refrigerant from high-temp, high-pressure vapor
into high-pressure, high-temp liquid
Metering Device - ✔✔reduces pressure of refrigerant and changes the high-pressure, high-temp liquid
into low pressure, low temp liquid.
Compound Gauge - ✔✔Typically blue and measures low pressure (psig) and vacuum (inHg).
High Pressure Gauge - ✔✔Red and measures high side (discharge) pressure. 0 to 500 psi
What does a compressor compress? - ✔✔Vapor
Why will refrigerant migrate to the crankcase in a compressor? - ✔✔Because of the vapor pressure
difference between refrigerant and oil
What color is the high pressure gauge? - ✔✔Red
What color is the low pressure gauge? - ✔✔Blue
What needs to happen if oil has been contaminated by burnout? - ✔✔Triple evacuate system, install
permanent filter-drier, conduct deep vacuum before recharging
What are three Rs of refrigeration? - ✔✔Recover, recycle, reclaim
100% Correct Answers | Verified | Latest
2024 Version
Are there drop-in replacements for R-12 systems? Why or why not? - ✔✔No because the new
refrigerants are incompatible with the oils and lubricants used in R-12 systems.
What type of oil is used in R-134a and what oils will it mix with? - ✔✔Ester based oils and they do not
mix with other oils
What type of lubricant is used with HCFCs? - ✔✔Alkylbenzene lubricant
What is difference b/w ternary blend a azeotropic blend? - ✔✔Ternary blends are three-part mixtures
whereas azeotropic blends are blends of two or more compounds that act like a single compound.
What is the trait of a hygroscopic lubricant? - ✔✔It absorbs (takes on) moisture
What is temperature glide and what type of blend won't have it? - ✔✔Temp. blend is the difference
between the dew point and the bubble point
Dew Point - ✔✔Occurs when saturation temp in evaporator causes refrigerant to change from liquid to
vapor
Bubble Point - ✔✔Occurs when saturation temp in condenser changes refrigerant from vapor to liquid
Will the gases in a ternary blend leak at the same rate? Why or why not? - ✔✔No because different
refrigerants in blend have different vapor pressures, causing them to leak at uneven rates
Refrigeration Process - ✔✔transfer of heat from one place to another
, Evaporator - ✔✔Absorbs heat into system from space to be cooled. Absorption of heat causes
refrigerant to boil. Upon leaving, refrigerant changed to low pressure, low temperature vapor
Compressor - ✔✔Takes low pressure, low temp vapor and changes it to a high-temp, high-pressure,
superheated vapor and delivers it to the condenser
Condenser - ✔✔Rejects heat from system and changes refrigerant from high-temp, high-pressure vapor
into high-pressure, high-temp liquid
Metering Device - ✔✔reduces pressure of refrigerant and changes the high-pressure, high-temp liquid
into low pressure, low temp liquid.
Compound Gauge - ✔✔Typically blue and measures low pressure (psig) and vacuum (inHg).
High Pressure Gauge - ✔✔Red and measures high side (discharge) pressure. 0 to 500 psi
What does a compressor compress? - ✔✔Vapor
Why will refrigerant migrate to the crankcase in a compressor? - ✔✔Because of the vapor pressure
difference between refrigerant and oil
What color is the high pressure gauge? - ✔✔Red
What color is the low pressure gauge? - ✔✔Blue
What needs to happen if oil has been contaminated by burnout? - ✔✔Triple evacuate system, install
permanent filter-drier, conduct deep vacuum before recharging
What are three Rs of refrigeration? - ✔✔Recover, recycle, reclaim
