HVAC: EPA 608 Certification Study
Guide, Top Exam Questions and
answers, rated A
Are there drop-in replacements for R-12 systems? Why or why not? - ✔✔-No because the new
refrigerants are incompatible with the oils
...
HVAC: EPA 608 Certification Study
Guide, Top Exam Questions and
answers, rated A
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
Recover - ✔✔-to remove any refrigerant in any condition from system and store in external container
without necessarily testing or processing in any way
Recycle - ✔✔-To clean refrigerant for immediate reuse by separating oil from refrigerant and removing
moisture and acidity from refrigerant by use of products like filter driers
Reclaim - ✔✔-To process refrigerant to level of new product specifications as determines by chemical
analysis
What standards must refrigerant recovery equipment meet and what components must all Type I and
Type II refrigerant systems have? - ✔✔-EPA-approved equipment testing organization. Service aperture
or process stub
System-Dependent Devices - ✔✔-Capture refrigerant with assistance of compressor and/or pressure of
refrigerant in appliances from which refrigerant is being recovered
Self-contained Devices - ✔✔-Have independent means to draw refrigerant out of appliances
What is nitrogen and a filter-drier used for after recovery? - ✔✔-Use nitrogen to flush debris out of
system after recovering refrigerant. Filter-drier should be installed to trap any debris that may cause
damage to new compressor
What must be done before starting an evacuation? - ✔✔-Recover all refrigerant and attain the
mandated vacuum level
ASHRAE Standard 15-1994 - ✔✔-Requires refrigerant sensor that will sound alarm and automatically
start ventilation system in occupied equipment rooms where refrigerant from leak will concentrate
How often should refillable cylinders be hydrostatically tested? - ✔✔-5 years
What are the three ways you can control fill level of refillable cylinder? - ✔✔-Mechanical floats,
electronic floats, or weight
What is the EPA definition of a small appliance? - ✔✔-One that is manufactured, charged, and
hermetically sealed in factory and contains five lbs. or less of refrigerant
What standards must recovery equipment manufactured before Nov. 15th, 1993 meet? - ✔✔-Capable
of recovering 80% of refrigerant whether or not compressor is operating or achieve a 4-inch vacuum
under conditions of ARI 740
What standards must recovery equipment manufactured AFTER Nov. 15th, 1993 meet? - ✔✔-Capable of
recovering 80% of refrigerant without compressor operating or achieve 4-inch vacuum under conditions
of ARI 740; be capable of recovering 90% of refrigerant with compressor operating or achieve 4-inch
vacuum under conditions of ARI 740; and must be approved by EPA approved third-party laboratory
Low-loss Fittings - ✔✔-Can be manually or au
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