EPA 608-øveprøve: Core, Type I, II og III

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Alle 15 spørgsmål i overblik

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1. 1. Which element, released when CFC molecules break apart in the stratosphere, destroys ozone?

   • A. Nitrogen
   • B. Chlorine
   • C. Carbon
   • D. Hydrogen
   Vis svar og forklaring

   Svar: B. Chlorine

   Ultraviolet light breaks CFC molecules apart high in the atmosphere and frees chlorine atoms. One chlorine atom can destroy thousands of ozone molecules because it is not used up in the reaction, which is why even small releases matter and why the Montreal Protocol targeted chlorine-containing refrigerants first.

2. 2. Which list ranks refrigerant types from the highest to the lowest ozone depletion potential?

   • A. CFCs, then HCFCs, then HFCs
   • B. HCFCs, then CFCs, then HFCs
   • C. HFCs, then HCFCs, then CFCs
   • D. CFCs, then HFCs, then HCFCs
   Vis svar og forklaring

   Svar: A. CFCs, then HCFCs, then HFCs

   CFCs such as R-12 contain the most chlorine and have the highest ozone depletion potential. HCFCs such as R-22 contain hydrogen, which makes them break down sooner in the lower atmosphere, so their potential is lower. HFCs such as R-134a and R-410A contain no chlorine, so they do not deplete ozone, although many of them are strong greenhouse gases.

3. 3. Complete the sentence.

   To _____ refrigerant means to reprocess it until it meets the purity specifications EPA sets for refrigerant sold for reuse, which must be confirmed by chemical analysis.

   Muligheder for felt 1: recover, recycle, reclaim, recharge

   Vis svar og forklaring

   Svar: reclaim

   Recover means removing refrigerant from an appliance and storing it in an external container. Recycle means cleaning it, usually by separating oil and filtering, for reuse in equipment of the same owner. Reclaim is the only one that brings refrigerant back to new product specifications, and it is done by an EPA-certified reclaimer, not in the field.

4. 4. You need to pressurize a system to check for leaks. What should you use?

   • A. Oxygen from a welding cylinder
   • B. Compressed shop air
   • C. Dry nitrogen through a pressure regulator and relief valve
   • D. Liquid refrigerant charged until the system reaches full pressure
   Vis svar og forklaring

   Svar: C. Dry nitrogen through a pressure regulator and relief valve

   Dry nitrogen is inert and contains no moisture. Oxygen can react violently with compressor oil and cause an explosion, and shop air brings in moisture and also contains oxygen. A nitrogen cylinder holds far more pressure than a system can take, so the regulator and relief valve are not optional.

5. 5. Which statements about the Clean Air Act venting prohibition are correct?

   Vælg alle, der passer.

   • A. Knowingly venting CFC or HCFC refrigerant during service, repair or disposal is prohibited.
   • B. The prohibition also covers HFC substitutes such as R-134a and R-410A.
   • C. Venting is allowed when a system holds less than 5 pounds of refrigerant.
   • D. Small de minimis releases that happen while you follow proper recovery practices are not a violation.
   • E. HFCs may be vented freely because they do not deplete ozone.
   Vis svar og forklaring

   Svar: A. Knowingly venting CFC or HCFC refrigerant during service, repair or disposal is prohibited., B. The prohibition also covers HFC substitutes such as R-134a and R-410A., D. Small de minimis releases that happen while you follow proper recovery practices are not a violation.

   The prohibition applies at servicing and at disposal, and it extends to substitute refrigerants like HFCs, not only to ozone-depleting ones. What is tolerated is the unavoidable minimal release that happens during good-faith recovery, such as the small amount lost when you disconnect hoses. Charge size does not create an exemption, and small appliances must still be recovered.

6. 6. Why should a refrigerant cylinder never be filled to more than 80 percent of its capacity?

   • A. Because EPA charges a fee on cylinders that are full
   • B. Because refrigerant cannot be recovered after the cylinder passes 80 percent
   • C. Because the scale reading becomes inaccurate above 80 percent
   • D. Because liquid expands as it warms, and a cylinder with no vapor space left can rupture
   Vis svar og forklaring

   Svar: D. Because liquid expands as it warms, and a cylinder with no vapor space left can rupture

   The space above the liquid gives it room to expand. If a full cylinder warms up, for example in a truck on a hot day, the liquid can fill the whole cylinder and hydrostatic pressure rises very fast. That is why recovery cylinders are weighed during filling, or have a float switch, and are never filled past 80 percent.

7. 7. Complete the sentence.

   Under Section 608, a small appliance is one that is fully manufactured, charged and hermetically sealed in a factory with _____ or less of refrigerant.

   Muligheder for felt 1: 1 pound, 2 pounds, 5 pounds, 10 pounds

   Vis svar og forklaring

   Svar: 5 pounds

   The definition has two parts: 5 pounds or less, and factory sealed. A household refrigerator, a window air conditioner or a dehumidifier qualifies. A unit that is field-assembled does not, even if its charge is small, and working on small appliances is what Type I certifies you for.

8. 8. You are recovering refrigerant from a small appliance whose compressor does not run, using recovery equipment made after November 15, 1993. What is the minimum requirement?

   • A. Recover 100 percent of the charge
   • B. Recover 90 percent of the charge
   • C. Recover 80 percent of the charge, or evacuate to 4 inches of mercury vacuum
   • D. Recover 50 percent of the charge
   Vis svar og forklaring

   Svar: C. Recover 80 percent of the charge, or evacuate to 4 inches of mercury vacuum

   With equipment made after that date, you must recover 90 percent of the charge when the appliance compressor works and 80 percent when it does not, or pull the appliance down to 4 inches of mercury vacuum in either case. A running compressor helps push refrigerant out, which is why the bar is higher when it works.

9. 9. When you recover from a small appliance with an inoperative compressor, why should you install access valves on both the high side and the low side?

   • A. Because refrigerant can stay trapped on one side of the system without a running compressor to move it
   • B. Because the law requires two valves on every appliance, whatever its size
   • C. Because a single valve would let air into the system
   • D. Because the high side valve is needed to add oil during recovery
   Vis svar og forklaring

   Svar: A. Because refrigerant can stay trapped on one side of the system without a running compressor to move it

   A working compressor moves refrigerant through the system, so one access point can be enough. When it does not run, refrigerant can be held on either side of the metering device, and accessing both sides gets it out faster and more completely. Solderless piercing valves used for this should be removed when the job is done, because they tend to leak over time.

10. 10. Complete the sentence.

    System-dependent recovery equipment may not be used on an appliance with a full charge of more than _____ of refrigerant, unless it is a pump-out unit permanently attached to the appliance.

    Muligheder for felt 1: 5 pounds, 15 pounds, 50 pounds, 200 pounds

    Vis svar og forklaring

    Svar: 15 pounds

    System-dependent equipment relies on the appliance's own compressor or pressure to move refrigerant, so it recovers too slowly and too incompletely for larger systems. Above 15 pounds you need self-contained recovery equipment, which has its own compressor and works without help from the appliance.

11. 11. A high-pressure appliance has a full charge of less than 200 pounds. Using recovery equipment made after November 15, 1993, to what level must you evacuate it before opening it?

    • A. 0 inches of mercury
    • B. 10 inches of mercury vacuum
    • C. 15 inches of mercury vacuum
    • D. 25 millimeters of mercury absolute
    Vis svar og forklaring

    Svar: A. 0 inches of mercury

    For high-pressure appliances, EPA's evacuation table sets 0 inches of mercury for a charge under 200 pounds and 10 inches of mercury vacuum for 200 pounds or more, with modern recovery equipment. The 25 millimeters of mercury absolute level belongs to low-pressure appliances. After you reach the level, wait a few minutes and watch the gauges, because a rise in pressure means refrigerant is still in the system.

12. 12. Which of these are signs of a leak in a high-pressure system?

    Vælg alle, der passer.

    • A. Oily residue around a fitting or brazed joint
    • B. Head pressure holding steady at its normal reading
    • C. Bubbles forming in a soap solution brushed over a joint
    • D. An electronic leak detector alarming at one spot
    • E. A clean, dry joint with no residue
    Vis svar og forklaring

    Svar: A. Oily residue around a fitting or brazed joint, C. Bubbles forming in a soap solution brushed over a joint, D. An electronic leak detector alarming at one spot

    Refrigerant carries compressor oil with it, so oil stains at a joint are the classic visual sign of a leak. Soap bubbles and an electronic detector confirm the exact spot. Before you charge or recharge equipment, leak test it, because adding refrigerant to a leaking system only releases more of it.

13. 13. On a large high-pressure system, why do technicians often start by recovering liquid refrigerant?

    • A. Because liquid recovery removes moisture from the system
    • B. Because liquid moves much more refrigerant in less time than vapor
    • C. Because vapor cannot legally be recovered
    • D. Because liquid recovery makes evacuation unnecessary
    Vis svar og forklaring

    Svar: B. Because liquid moves much more refrigerant in less time than vapor

    The same volume of liquid holds far more refrigerant than vapor, so pulling liquid first removes most of the charge quickly. You still have to recover the vapor afterwards and reach the required evacuation level. Shorter hoses, larger diameter hoses and removing valve cores also speed up recovery.

14. 14. When you recharge a low-pressure chiller that has been evacuated to a deep vacuum, why do you add refrigerant vapor before liquid?

    • A. Because liquid would contaminate the purge unit
    • B. Because vapor is cheaper than liquid
    • C. Because the chiller can only be charged through the condenser
    • D. Because liquid boiling at very low pressure can freeze the water in the tubes
    Vis svar og forklaring

    Svar: D. Because liquid boiling at very low pressure can freeze the water in the tubes

    At a deep vacuum, liquid refrigerant flashes and gets very cold, cold enough to freeze the water in the evaporator tubes and split them. Charging vapor first raises the pressure until the refrigerant's saturation temperature is above freezing, and then liquid can follow. Centrifugal chillers are charged through the evaporator charging valve.

15. 15. Which statements about low-pressure chillers are correct?

    Vælg alle, der passer.

    • A. They run at higher pressures than R-410A systems.
    • B. Because parts of the system run below atmospheric pressure, leaks let air and moisture in rather than letting refrigerant out.
    • C. A purge unit removes air and other noncondensables from the system.
    • D. Leak testing should be done by pressurizing the system with oxygen.
    • E. During refrigerant evacuation, the water in the tubes should be circulated or drained to prevent freezing.
    Vis svar og forklaring

    Svar: B. Because parts of the system run below atmospheric pressure, leaks let air and moisture in rather than letting refrigerant out., C. A purge unit removes air and other noncondensables from the system., E. During refrigerant evacuation, the water in the tubes should be circulated or drained to prevent freezing.

    Low-pressure refrigerants such as R-123 boil just above room temperature at atmospheric pressure, so the evaporator of a running chiller sits in a vacuum and a leak pulls air in. That air and moisture raise pressure and cut efficiency, which is what the purge unit is there to remove. Water in the tubes can freeze as pressure drops during evacuation, so keep it moving or drain it.

Sådan fungerer EPA 608-prøven

Section 608 i Clean Air Act kræver, at alle, der vedligeholder, servicerer, reparerer eller bortskaffer udstyr, der kan slippe kølemiddel ud, er certificerede. Reglen er føderal, så den samme certificering gælder i alle delstater. Der er fire certificeringstyper. Type I dækker små apparater, det vil sige enheder, der er lukket fra fabrikken med 5 pounds kølemiddel eller mindre, som køleskabe i hjemmet og aircondition-enheder til vinduer. Type II dækker udstyr med højt og meget højt tryk, hvilket omfatter det meste aircondition i boliger og erhverv. Type III dækker lavtryksudstyr, primært centrifugalkølere. Universal betyder, at du har bestået alle tre typer.

Hver prøve indeholder en Core-sektion. Ifølge EPA's regel har hver prøve mindst 25 spørgsmål fra Core-gruppen og mindst 25 fra hver type, du certificeres i, så en Universal-prøve har 100 spørgsmål. Beståelsesgrænsen i reglen er 70 procent for Type I-, Type II-, Type III- og Universal-prøverne uden hjælpemidler og 84 procent for en Type I-prøve, der tages som brevprøve. Type II og Type III skal tages uden hjælpemidler og med en tilsynsførende. En Type I-brevprøve eller en Core-sektion taget med hjælpemidler kan ikke bruges til Universal.

EPA afholder ikke selv prøven og udsteder ikke selv kortene. Du går op hos en EPA-godkendt certificeringsorganisation, som udsteder et certifikat i kortformat inden for 30 dage. Certificeringen udløber ikke, og du skal opbevare en kopi af dit certifikat på din arbejdsplads. Priser, tidspunkter, og om du kan tage prøven online, bestemmer den organisation, du vælger. Én ting overrasker ofte folk: aircondition i biler hører ikke under Section 608. Arbejde på aircondition i motorkøretøjer hører under Section 609, som er en særskilt certificering.

Sådan bruger du smagsprøven

De 15 spørgsmål følger prøvens rækkefølge: seks Core-spørgsmål, derefter tre til Type I, fire til Type II og to til Type III. Skal du kun op i Core og Type I, så tag dem alle alligevel, for Type II-spørgsmålene om genvindingshastighed og tegn på lækager er nyttig baggrundsviden for enhver tekniker.

Tre emner fortjener ekstra opmærksomhed. Det første er de tre R'er, recover, recycle og reclaim, altså at opsamle, rense og oparbejde kølemidlet, som er lette at blande sammen. Det andet er evakueringstabellen, hvor det krævede vakuum afhænger af apparattypen, fyldningens størrelse og hvornår dit genvindingsudstyr er fremstillet. Det tredje er sikkerhed, især kvælstof kontra ilt og grænsen på 80 procent for påfyldning af flasker. Misser du et af dem her, så repetér hele emnet, ikke kun det enkelte faktum.

Nogle tal i prøven har ændret sig gennem årene, blandt andet grænserne for reparation af lækager, udfasningsdatoer og den maksimale bøde, og nyere regler under AIM Act dækker nu også HFC-udstyr. Denne smagsprøve tester begreberne bag reglerne frem for tal, der flytter sig. Før din prøve skal du tjekke de gældende krav på EPA's sider om Section 608 på epa.gov og i studiemanualen fra din certificeringsorganisation.

Sådan bygger StudyPDF fulde EPA 608-øveprøver ud fra din manual

Femten spørgsmål kan vise dig, hvilken sektion der er usikker. De kan ikke dække en Universal-prøve med 100 spørgsmål, og en generisk spørgsmålspulje rammer sjældent den studiemanual, din certificeringsorganisation giver dig.

StudyPDF tager i stedet udgangspunkt i dit materiale. Upload din EPA 608-studiemanual, slides fra din erhvervsskole eller billeder af dine noter fra timerne, tryk på Nyt materiale, og StudyPDF bygger øveeksamener ud fra præcis de sider, delt op i sektioner som den rigtige prøve og rettet til sidst. Hvert spørgsmål bygger på dit materiale, og hver forklaring henviser til, hvor svaret kommer fra.

Du behøver ikke et dokument for at komme i gang. Nævn i stedet et emne, for eksempel genvinding ved Type III eller de tre R'er, og Bo sætter det op med de vigtigste begreber, så du kan bygge quizzer på det. Dine resultater holder styr på, hvilke begreber du bliver ved med at ramme forkert, så næste quiz kan gå efter dem. Det er gratis at starte, og gratisplanen dækker cirka fire materialer om ugen.