EPA 608 øvingsprøve: Core, Type I, II, III

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Alle 15 spørsmål i oversikt

Vil du heller lese før du spiller? Alle spørsmålene i smakebiten står listet under. Svar og forklaringer er skjult til du åpner dem.

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.

   Alternativer for luke 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?

   Velg alle som 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.

   Alternativer for luke 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.

    Alternativer for luke 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?

    Velg alle som 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?

    Velg alle som 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.

Slik fungerer EPA 608-eksamen

Section 608 i den amerikanske Clean Air Act krever at alle som vedlikeholder, utfører service på, reparerer eller kasserer utstyr som kan slippe ut kuldemedium, er sertifisert. Regelen er føderal, så den samme sertifiseringen gjelder i alle delstater. Det finnes fire sertifiseringstyper. Type I dekker små apparater, det vil si enheter som er forseglet på fabrikken med 5 pund kuldemedium eller mindre, som kjøleskap i husholdningen og vinduaggregater. Type II dekker utstyr med høyt og svært høyt trykk, som omfatter det meste av klimaanlegg i boliger og næringsbygg. Type III dekker lavtrykksutstyr, hovedsakelig sentrifugalkjølere. Universal betyr at du har bestått alle tre typene.

Hver prøve har en Core-del. Etter regelverket fra EPA, den amerikanske miljømyndigheten, har hver prøve minst 25 spørsmål fra Core-gruppen og minst 25 fra hver type du sertifiserer deg for, så en Universal-eksamen har 100 spørsmål. Grensen for bestått i regelverket er 70 prosent for Type I, Type II, Type III og Universal tatt uten hjelpemidler, og 84 prosent for en Type I-prøve tatt i postformatet. Type II og Type III må tas uten hjelpemidler og med tilsyn. En Type I-prøve tatt per post, eller en Core-del tatt med hjelpemidler, kan ikke brukes mot Universal.

EPA arrangerer ikke eksamen og skriver ikke ut kortene selv. Du tar prøven hos en sertifiseringsorganisasjon godkjent av EPA, som utsteder et lommekort innen 30 dager. Sertifiseringen utløper ikke, og du må oppbevare en kopi av sertifikatet på arbeidsstedet ditt. Pris, timebestilling og om du kan ta prøven på nett, bestemmes av organisasjonen du velger. En ting som ofte overrasker: klimaanlegg i biler hører ikke under Section 608. Arbeid på klimaanlegg i motorkjøretøy faller inn under Section 609, som er en egen sertifisering.

Slik bruker du denne smakebiten

De 15 spørsmålene følger rekkefølgen i eksamen: seks Core-spørsmål, deretter tre til Type I, fire til Type II og to til Type III. Skal du bare ta Core og Type I, tar du likevel alle sammen, fordi Type II-spørsmålene om hvor raskt kuldemediet samles opp og om tegn på lekkasje er nyttig bakgrunn for enhver tekniker.

Tre temaer fortjener ekstra oppmerksomhet. Det første er de tre R-ene, recover, recycle og reclaim (oppsamling, resirkulering og regenerering), som er lette å blande sammen. Det andre er evakueringstabellen, der vakuumet som kreves, avhenger av apparattypen, fyllingsmengden og når oppsamlingsutstyret ditt ble produsert. Det tredje er sikkerhet, særlig nitrogen kontra oksygen og grensen på 80 prosent fylling av flasker. Bommer du på ett av disse her, repeterer du hele temaet, ikke bare det ene faktumet.

Noen tall på eksamen har endret seg gjennom årene, blant annet grensene for lekkasjereparasjon, utfasingsdatoer og den høyeste boten, og nyere regler under AIM Act dekker nå også HFK-utstyr. Denne smakebiten tester begrepene bak reglene i stedet for tall som flytter seg. Før eksamen bør du sjekke gjeldende krav på EPAs sider om Section 608 på epa.gov og i studiemanualen fra sertifiseringsorganisasjonen din.

Slik bygger StudyPDF fullstendige EPA 608-øvingsprøver fra manualen din

Femten spørsmål kan vise deg hvilken del som sitter dårlig. De kan ikke dekke en Universal-eksamen på 100 spørsmål, og en generell spørsmålsbank passer sjelden med studiemanualen sertifiseringsorganisasjonen din gir deg.

StudyPDF tar i stedet utgangspunkt i ditt materiale. Last opp studiemanualen til EPA 608, lysark fra fagskolen eller bilder av notatene dine, trykk på Nytt materiale, så bygger StudyPDF øvingseksamener fra akkurat de sidene, delt inn som den ekte prøven og rettet til slutt. Hvert spørsmål er forankret i materialet ditt, og hver forklaring viser hvor svaret kommer fra.

Du trenger ikke et dokument for å begynne. Nevn heller et tema, for eksempel oppsamling i Type III eller de tre R-ene, så setter Bo det opp med nøkkelbegrepene, slik at du kan lage quizer om det. Resultatene dine viser hvilke begreper du stadig bommer på, så neste quiz kan sikte mot dem. Det er gratis å starte, og gratisplanen dekker omtrent fire materialer i uka.