EPA Section 608 Technician Certification
Study Guide
What are the typical uses of the center port of gauge set? - ANSUsed during evacuation,
charging and recovery procedures.
What color are the gauges on a manifold gauge set? - ANSLow pressure is blue, High pressure
is red.
What are the typical ranges of pressure measurements used on the gauges of a manifold gauge
set? - ANSHigh side is 0 to 500 PSIG; Low side is 0 to 350 PSIG and 0 to 30 in. Hg below
atmospheric pressure.
Is the refrigerant leaving a condenser at a high or low pressure? Is it a liquid or a gas? -
ANSHigh pressure, liquid.
Is the refrigerant entering the expansion valve (variable metering device) a liquid or gas? -
ANSLiquid, high pressure.
Is the pressure of the refrigerant entering the compressor high or low? - ANSLow pressure
vapor.
Where in a refrigerant circuit does a liquid boil to absorb heat? - ANSIn the evaporator.
The refrigerant in the suction line is a gas that has been heated above its saturation. What is
this condition called? - ANSSuperheated vapor.
What can cause liquid refrigerant to migrate to a compressor crankcase? - ANSIf the
compressor is located in the coldest location in the circuit.
List two conditions that can quickly damage a compressor that is starting to run? -
ANSOperating while in a deep vacuum or when the service valves are closed.
What system failures require taking an oil sample? - ANSA compressor burnout or if the unit has
had a leak.
Is flushing with refrigerant an acceptable tube cleaning method? - ANSNo.
In addition to preventing and repairing leaks what else should a technician do to conserve
refrigerant? - ANSRecover and recycle used refrigerants.
,What factors affect the speed of an evacuation? - ANSPump size, hose length, hose diameter,
size of system to be evacuated, ambient temperature, suction line size, and the amount of
moisture in the system.
How should gauge set hoses be sized for use in evacuating a system? - ANSUse the shortest
length and the largest diameter possible for the quickest evacuation. At least as large as the
vacuum pump inlet.
When evacuating what is the benefit of using short hoses with large diameters? - ANSReduces
emissions, pressure drop and evacuation time.
Which connection determines the preferred size of hoses used with a vacuum pump? - ANSThe
vacuum pump inlet.
As the capacity and suction hose size increase what happens to the time needed for an
evacuation? - ANSTime is reduced.
What purpose is served by heating a system during dehydration? - ANSTo speed up moisture
removal.
Does a thorough evacuation remove moisture from a system? - ANSYes.
What can happen to oil in the compressor if the moisture is left in an operating system? -
ANSThe oil will form hydrofluoric and hydrochloric acids which will corrode the internal parts of
the system.
What is the result of over-evacuating a system? - ANSNo damage will be done.
How can a system be leak checked using a low pressure gauge? - ANSVacuum reading will rise
when vacuum pump is turned off.
How close should the vacuum gauge be connected to the vacuum pump during evacuation? -
ANSAs far away as possible.
When measuring the vacuum of a system being evacuated the system must be isolated. What
must be done to the vacuum pump? - ANSTurn it off and valve it off.
What is ozone? - ANS3 atoms of oxygen. It blocks much of the harmful ultraviolet radiation
(uv-b) emitted from the sun and it keeps our earth's temperature stable.
How much ozone can a chlorine atom destroy in the stratosphere? - ANSOne atom can destroy
100,000 ozone molecules.
, What is Ozone Depletion Potential (ODP)? - ANSThe ability of any chemical to deplete the
ozone layer.
What is CFC? - ANSChlorofluorocarbon.
Which refrigerants are CFC's? - ANSR-11,12,113,114.
Which chemical in the CFC refrigerants does the most damage to the ozone layer? -
ANSChlorine.
What is an HCFC? - ANSHydrochlorofluorocarbons.
Which refrigerants are HCFC's? - ANSR-22,123.
Which is more harmful to the ozone layer a CFC or an HCFC? - ANSCFC's.
What is it about CFC's that make them more harmful to the stratosphere? - ANSChemical
strength, they will not breakdown in the lower atmosphere.
What is an HFC? - ANSA fluorocarbon that contains no chlorine.
Which refrigerants are HFC's? - ANSR-134a,404a,407c,410a.
What is the ODP of the HFC refrigerant? - ANSZero.
Which refrigerants contain chlorine? - ANSCFC's and HCFC's.
Which refrigerants have high ODP? - ANSCFC's.
Which refrigerants have low ODP? - ANSHCFC's, HFC's are zero.
What is an azeotrope refrigerant? - ANSA mixture of two or more compounds where the mixture
behaves like a single chemical.
Is one of the components of R-500 a CFC? - ANSYes
Does stratospheric ozone help or hurt the work of the earth's protective shield? - ANSIt helps.
What chemical in the stratosphere tells us ozone depletion is occurring? -
ANSChlorine-monoxide.
How do we know the chlorine in the stratosphere is coming from CFC's? - ANSThe increase in
chlorine and fluorine present in the stratosphere, matches the increase in emissions of CFC's.
Study Guide
What are the typical uses of the center port of gauge set? - ANSUsed during evacuation,
charging and recovery procedures.
What color are the gauges on a manifold gauge set? - ANSLow pressure is blue, High pressure
is red.
What are the typical ranges of pressure measurements used on the gauges of a manifold gauge
set? - ANSHigh side is 0 to 500 PSIG; Low side is 0 to 350 PSIG and 0 to 30 in. Hg below
atmospheric pressure.
Is the refrigerant leaving a condenser at a high or low pressure? Is it a liquid or a gas? -
ANSHigh pressure, liquid.
Is the refrigerant entering the expansion valve (variable metering device) a liquid or gas? -
ANSLiquid, high pressure.
Is the pressure of the refrigerant entering the compressor high or low? - ANSLow pressure
vapor.
Where in a refrigerant circuit does a liquid boil to absorb heat? - ANSIn the evaporator.
The refrigerant in the suction line is a gas that has been heated above its saturation. What is
this condition called? - ANSSuperheated vapor.
What can cause liquid refrigerant to migrate to a compressor crankcase? - ANSIf the
compressor is located in the coldest location in the circuit.
List two conditions that can quickly damage a compressor that is starting to run? -
ANSOperating while in a deep vacuum or when the service valves are closed.
What system failures require taking an oil sample? - ANSA compressor burnout or if the unit has
had a leak.
Is flushing with refrigerant an acceptable tube cleaning method? - ANSNo.
In addition to preventing and repairing leaks what else should a technician do to conserve
refrigerant? - ANSRecover and recycle used refrigerants.
,What factors affect the speed of an evacuation? - ANSPump size, hose length, hose diameter,
size of system to be evacuated, ambient temperature, suction line size, and the amount of
moisture in the system.
How should gauge set hoses be sized for use in evacuating a system? - ANSUse the shortest
length and the largest diameter possible for the quickest evacuation. At least as large as the
vacuum pump inlet.
When evacuating what is the benefit of using short hoses with large diameters? - ANSReduces
emissions, pressure drop and evacuation time.
Which connection determines the preferred size of hoses used with a vacuum pump? - ANSThe
vacuum pump inlet.
As the capacity and suction hose size increase what happens to the time needed for an
evacuation? - ANSTime is reduced.
What purpose is served by heating a system during dehydration? - ANSTo speed up moisture
removal.
Does a thorough evacuation remove moisture from a system? - ANSYes.
What can happen to oil in the compressor if the moisture is left in an operating system? -
ANSThe oil will form hydrofluoric and hydrochloric acids which will corrode the internal parts of
the system.
What is the result of over-evacuating a system? - ANSNo damage will be done.
How can a system be leak checked using a low pressure gauge? - ANSVacuum reading will rise
when vacuum pump is turned off.
How close should the vacuum gauge be connected to the vacuum pump during evacuation? -
ANSAs far away as possible.
When measuring the vacuum of a system being evacuated the system must be isolated. What
must be done to the vacuum pump? - ANSTurn it off and valve it off.
What is ozone? - ANS3 atoms of oxygen. It blocks much of the harmful ultraviolet radiation
(uv-b) emitted from the sun and it keeps our earth's temperature stable.
How much ozone can a chlorine atom destroy in the stratosphere? - ANSOne atom can destroy
100,000 ozone molecules.
, What is Ozone Depletion Potential (ODP)? - ANSThe ability of any chemical to deplete the
ozone layer.
What is CFC? - ANSChlorofluorocarbon.
Which refrigerants are CFC's? - ANSR-11,12,113,114.
Which chemical in the CFC refrigerants does the most damage to the ozone layer? -
ANSChlorine.
What is an HCFC? - ANSHydrochlorofluorocarbons.
Which refrigerants are HCFC's? - ANSR-22,123.
Which is more harmful to the ozone layer a CFC or an HCFC? - ANSCFC's.
What is it about CFC's that make them more harmful to the stratosphere? - ANSChemical
strength, they will not breakdown in the lower atmosphere.
What is an HFC? - ANSA fluorocarbon that contains no chlorine.
Which refrigerants are HFC's? - ANSR-134a,404a,407c,410a.
What is the ODP of the HFC refrigerant? - ANSZero.
Which refrigerants contain chlorine? - ANSCFC's and HCFC's.
Which refrigerants have high ODP? - ANSCFC's.
Which refrigerants have low ODP? - ANSHCFC's, HFC's are zero.
What is an azeotrope refrigerant? - ANSA mixture of two or more compounds where the mixture
behaves like a single chemical.
Is one of the components of R-500 a CFC? - ANSYes
Does stratospheric ozone help or hurt the work of the earth's protective shield? - ANSIt helps.
What chemical in the stratosphere tells us ozone depletion is occurring? -
ANSChlorine-monoxide.
How do we know the chlorine in the stratosphere is coming from CFC's? - ANSThe increase in
chlorine and fluorine present in the stratosphere, matches the increase in emissions of CFC's.
