The EPA 608 Core section

Answer: B. absorbs heat from the surroundings and converts the refrigerant from a liquid to a vapor

• AThat is the condenser's job: it rejects heat and condenses high-pressure vapor into liquid.
• BCorrect: the evaporator absorbs heat from the space or product, and that heat boils the low-pressure liquid refrigerant into vapor.
• CRefrigerant leaves the evaporator slightly superheated, but the evaporator's main job is boiling liquid into vapor, not holding superheated vapor.
• DRaising pressure and temperature is the compressor's job, not the evaporator's.

In the refrigeration cycle, the evaporator absorbs heat from the space or product. That heat boils the low-pressure liquid refrigerant into a low-pressure vapor.

Answer: D. It helps identify the presence of non-condensable gases based on pressure readings

• AA P-T chart has no time or flow data, so it cannot give a recovery rate.
• BMoisture is checked with an acid/moisture test kit or a moisture indicator, not a P-T chart.
• CA P-T chart says nothing about electrical efficiency; it relates refrigerant pressure to temperature.
• DCorrect: if a stable cylinder's pressure is higher than the P-T chart value for its temperature, non-condensables such as air are likely present.

A pressure-temperature (P-T) chart shows the relationship between refrigerant pressure and temperature, allowing technicians to verify if the correct refrigerant is present and identify non-condensable gases based on pressure readings.

Answer: C. There is likely an issue with excess air or non-condensables in the system

• ALow oil hurts lubrication and can damage the compressor, but it does not typically raise discharge pressure during charging.
• BThe evaporator absorbs heat on the low side; it does not 'overheat' in a way that drives up discharge pressure.
• CCorrect: air and other non-condensables collect in the condenser, take up space and do not condense, so head (discharge) pressure climbs.
• DHow full the supply tank is does not change the system's discharge pressure; overcharging the system is a different problem.

An unexpected rise in discharge pressure during charging may indicate the presence of air or non-condensable gases in the system. These gases do not condense under system pressures and can lead to increased pressure readings.

Answer: C. Proper DOT shipping documentation

• AThere is no reclamation tax to pay before shipping recovered refrigerant.
• BRefrigerant is never 'converted' to liquid nitrogen; nitrogen is a separate gas.
• CCorrect: recovered refrigerant is a regulated hazardous material in transport, so cylinders need proper DOT labels and shipping papers.
• DSection 608 certification does not expire, and renewal has nothing to do with shipping.

When shipping recovered refrigerant to a reclamation facility, proper DOT shipping documentation must be completed, including hazardous material information, contents, quantity, and handling instructions.

Answer: B. Verify the valves and connections are completely leak-tight

• ARecovery cylinders are gray with a yellow top; painting them orange is not a requirement.
• BCorrect: valves and connections must be checked leak-tight so refrigerant cannot escape during transit.
• CReleasing gas from a recovery cylinder before shipping risks venting refrigerant and is not a pre-transport requirement.
• DPurging a filled recovery cylinder with nitrogen would push refrigerant out; it is not a transport step.

DOT shipping rules (listed in EPA's test topics) call for a cylinder of recovered refrigerant to be labeled and checked for leak-tight valves and connections before it travels, so none of it escapes in transit.

Answer: B. Pressure relief device

• AA temperature gauge is not a required safety device on a recovery cylinder.
• BCorrect: a pressure relief device lets the cylinder vent before it ruptures if it is overheated or overpressurized.
• CFlow meters are not part of a recovery cylinder; fill is controlled by weight or a float switch.
• DA float or level device can help prevent overfilling, but the safety feature every cylinder must have is pressure relief.

All recovery cylinders must have a pressure relief device to prevent dangerous over-pressurization.

Answer: B. Check system pressure with gauges

• AVentilation is good practice, but it does not tell you whether the system is under pressure.
• BCorrect: connect gauges and check the pressure first so you know whether refrigerant must be recovered before the system is opened.
• CStarting recovery equipment before you know the system's condition is out of order; you check pressure first.
• DYou find out what is in the system by reading the gauges; assuming it is empty is how injuries and venting happen.

Before opening any refrigeration system, a technician must verify the system pressure using gauges to prevent potential injury from pressurized refrigerant and to avoid refrigerant release to the atmosphere.

Answer: D. With a vacuum gauge or micron gauge

• AA standard compound gauge cannot read deep vacuum accurately; it is too coarse in the micron range.
• BA thermometer measures temperature, not vacuum level.
• CA refrigerant analyzer identifies refrigerant type and purity; it does not measure vacuum.
• DCorrect: a vacuum (micron) gauge reads the very low absolute pressures reached during evacuation.

Technicians measure vacuum levels during system evacuation using a vacuum gauge or micron gauge, which provides accurate readings of deep vacuum levels needed to remove moisture and non-condensables.

Answer: D. Three years

• ATwelve months is too short; Section 608 recordkeeping is generally three years.
• BSeven years is longer than the rule requires.
• CFive years is also wrong; the standard retention period under Section 608 is three years.
• DCorrect: Section 608 records such as recovery and disposal records are kept for three years.

Records of refrigerant sent for reclamation or disposal are kept for three years, like other Section 608 records.

Answer: D. Because it is dry, inert, and non-flammable

• ANitrogen does not seal leaks; it only pressurizes the system so leaks can be found.
• BNitrogen does not follow a refrigerant's P-T relationship; it stays a gas at system conditions.
• CNitrogen used for a leak test is not recovered; as an exempt gas it may be released after testing.
• DCorrect: dry nitrogen is inert, adds no moisture, cannot burn and will not react with oil, so it is the safe test gas.

Nitrogen is used for pressure testing because it is dry, inert, and non-flammable, which prevents potential system contamination or chemical reactions while safely identifying leaks without using valuable or harmful refrigerants.

Answer: C. It breaks down and destroys ozone molecules

• AChlorine does not form a protective layer; the ozone layer is what protects Earth, and chlorine destroys it.
• BChlorine does not neutralize greenhouse gases; many CFCs are themselves strong greenhouse gases.
• CCorrect: UV light frees chlorine atoms from CFCs, and each chlorine atom can destroy thousands of ozone molecules in a chain reaction.
• DForming water is not the ozone chemistry here; chlorine attacks ozone (O3), not hydrogen.

When ultraviolet radiation hits CFC molecules in the stratosphere, they break down and release chlorine atoms. Each chlorine atom can destroy thousands of ozone molecules through a catalytic reaction.

Answer: C. HFCs (Hydrofluorocarbons)

• AHCFCs still contain chlorine, so their ODP is low but not zero.
• BChlorocarbons contain chlorine and deplete ozone.
• CCorrect: HFCs contain no chlorine, so their ozone depletion potential is zero (though many have a high global warming potential).
• DCFCs contain the most chlorine and have the highest ODP.

HFCs (Hydrofluorocarbons) do not contain chlorine and therefore have zero ozone depletion potential, unlike CFCs and HCFCs which contain chlorine that damages the ozone layer.

Answer: B. Never

• ARoutine maintenance is not an excuse; refrigerant must be recovered, not vented.
• BCorrect: knowingly venting refrigerant is prohibited; only de minimis releases during proper recovery and exempt substitutes like nitrogen or CO2 are allowed.
• CHigh pressure is handled by relief devices and recovery, not by intentional venting.
• DEmergency repairs do not create an exception to the venting prohibition.

Knowingly venting refrigerant during service, maintenance, repair or disposal is prohibited under Section 608 of the Clean Air Act. The only exceptions are de minimis releases made while following the required practices and refrigerants EPA lists as exempt for specific end-uses.

Answer: A. Cleaning refrigerant for reuse by removing oil and particulates

• ACorrect: recycling cleans refrigerant through oil separation and filter-driers so it can be reused, typically in equipment of the same owner.
• BMixing refrigerants creates contamination; it is never a recycling step.
• CRecycling keeps the refrigerant the same chemical; it does not turn it into something else.
• DDisposal is the end of the line; recycling is about reuse.

Recycling refrigerant involves cleaning refrigerant for reuse by removing oil, acid, and particulate matter through basic processes such as oil separation and single or multiple passes through filter-driers.

Answer: B. Pressure and saturation temperature drop

• APressure and saturation temperature move together, so one cannot drop while the other rises.
• BCorrect: less air-side load boils less refrigerant, so evaporator pressure falls and its saturation temperature falls with it.
• CPressure and saturation temperature are tied on the P-T curve, so they cannot move in opposite directions.
• DRising pressure and temperature come from more load, not less.

A sudden load drop reduces heat absorption, causing less refrigerant vaporization. This decreases the suction pressure at the expansion device outlet, which proportionately lowers saturation temperature.

Answer: A. Use of weight scales

• ACorrect: a scale lets you weigh the cylinder so you know how much moved and never fill past 80% by weight.
• BTemperature sensors do not tell you how much refrigerant is in the receiving cylinder.
• CA level indicator is not the standard way to measure transfers; weighing on a scale is.
• DPressure does not show how full a cylinder is, because the pressure stays the same as long as there is liquid inside.

Weigh the receiving cylinder on a scale during the transfer. The scale shows how much has moved and keeps the cylinder from being filled past 80% of its capacity.

Answer: D. Processing used refrigerant to meet the same purity standards as new, virgin refrigerant

• ACollecting refrigerant from a system is recovery, not reclaim.
• BReclaim keeps the same refrigerant; it does not convert one type into another.
• CCleaning for reuse in the same owner's equipment is recycling, not reclaim.
• DCorrect: reclaim reprocesses used refrigerant to AHRI 700 (new-product) purity, verified by chemical analysis.

Reclaiming refrigerant means processing used refrigerant to meet the same purity standards as new, virgin refrigerant, verified by chemical analysis. This is different from recycling or recovery.

Answer: C. Stable, known condition

• AReading at an elevated temperature does not help unless the temperature is known and steady.
• BAn unusually low temperature is not required; what matters is that it is stable and known.
• CCorrect: compare pressure to the P-T chart only when the refrigerant has settled at a stable, known temperature, or the comparison is meaningless.
• DA chilled room is not required; any stable, known temperature works.

For an accurate reading, measure refrigerant pressure at a stable, known temperature. Only then can it be compared with a pressure-temperature chart to check for contamination.