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

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Alle 15 vragen op een rij

Liever eerst lezen? Hieronder staat elke vraag uit deze oefentoets. Antwoorden en uitleg blijven ingeklapt tot je ze opent.

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

   • A. Nitrogen
   • B. Chlorine
   • C. Carbon
   • D. Hydrogen
   Toon antwoord en uitleg

   Antwoord: 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
   Toon antwoord en uitleg

   Antwoord: 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.

   Opties voor invulveld 1: recover, recycle, reclaim, recharge

   Toon antwoord en uitleg

   Antwoord: 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
   Toon antwoord en uitleg

   Antwoord: 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?

   Selecteer alles wat van toepassing is.

   • 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.
   Toon antwoord en uitleg

   Antwoord: 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
   Toon antwoord en uitleg

   Antwoord: 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.

   Opties voor invulveld 1: 1 pound, 2 pounds, 5 pounds, 10 pounds

   Toon antwoord en uitleg

   Antwoord: 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
   Toon antwoord en uitleg

   Antwoord: 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
   Toon antwoord en uitleg

   Antwoord: 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.

    Opties voor invulveld 1: 5 pounds, 15 pounds, 50 pounds, 200 pounds

    Toon antwoord en uitleg

    Antwoord: 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
    Toon antwoord en uitleg

    Antwoord: 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?

    Selecteer alles wat van toepassing is.

    • 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
    Toon antwoord en uitleg

    Antwoord: 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
    Toon antwoord en uitleg

    Antwoord: 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
    Toon antwoord en uitleg

    Antwoord: 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?

    Selecteer alles wat van toepassing is.

    • 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.
    Toon antwoord en uitleg

    Antwoord: 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.

Hoe het EPA 608-examen werkt

Section 608 van de Clean Air Act, de Amerikaanse federale wet op de luchtkwaliteit, verplicht iedereen die apparatuur onderhoudt, servicet, repareert of afvoert waaruit koudemiddel kan vrijkomen om gecertificeerd te zijn. De regel is federaal, dus dezelfde certificering geldt in elke Amerikaanse staat. Er zijn vier certificeringstypes. Type I gaat over kleine apparaten, dat wil zeggen units die in de fabriek zijn afgesloten met 5 pound (lb) koudemiddel of minder, zoals koelkasten voor thuis en raamairco's. Type II gaat over apparatuur onder hoge en zeer hoge druk, waaronder de meeste airconditioning in woningen en bedrijven. Type III gaat over lagedrukapparatuur, vooral centrifugaalchillers. Universal betekent dat je voor alle drie de types geslaagd bent.

Elke test heeft een Core-deel. Volgens de regel van de EPA heeft elke test minstens 25 vragen uit de Core-groep en minstens 25 uit elk type waarvoor je je certificeert, dus een Universal-examen heeft 100 vragen. De slaaggrens in de regel is 70 procent voor de tests van Type I, Type II, Type III en Universal zonder hulpmiddelen (closed book), en 84 procent voor een Type I-test die per post wordt gemaakt. Type II en Type III moeten zonder hulpmiddelen en onder toezicht worden gemaakt. Een Type I-test per post, of een Core-deel dat met open boek is gemaakt, telt niet mee voor Universal.

De EPA neemt het examen niet zelf af en drukt ook zelf geen pasjes. Je doet de test bij een door de EPA erkende certificerende organisatie, die binnen 30 dagen een pasje uitgeeft. De certificering verloopt niet, en je moet een kopie van je certificaat op je werkplek bewaren. Prijzen, planning en of je online kunt testen bepaalt de organisatie die je kiest. Iets wat mensen vaak verrast: airconditioning in auto's valt niet onder Section 608. Werk aan de airco van motorvoertuigen valt onder Section 609, een aparte certificering.

Zo gebruik je deze oefentoets

De 15 vragen volgen de volgorde van het examen: zes Core-vragen, dan drie voor Type I, vier voor Type II en twee voor Type III. Doe je alleen Core en Type I, maak ze dan toch allemaal, want de Type II-vragen over terugwinsnelheid en tekenen van lekkage zijn nuttige achtergrond voor elke monteur.

Drie onderwerpen verdienen extra aandacht. Het eerste zijn de drie R's, recover, recycle en reclaim (terugwinnen, recyclen en opwerken), die je makkelijk door elkaar haalt. Het tweede is de vacuümtabel, waarin het vereiste vacuüm afhangt van het type apparaat, de grootte van de vulling en wanneer je terugwinapparatuur is gemaakt. Het derde is veiligheid, vooral stikstof tegenover zuurstof en de vulgrens van 80 procent voor cilinders. Mis je hier een van deze, herhaal dan het hele onderwerp, niet alleen dat ene feit.

Sommige getallen op het examen zijn door de jaren heen veranderd, waaronder de drempels voor lekreparatie, de uitfaseringsdata en de maximale boete, en nieuwere regels onder de AIM Act gelden nu ook voor HFK-apparatuur. Deze oefentoets toetst de begrippen achter die regels in plaats van getallen die verschuiven. Controleer voor je examen de actuele eisen op de pagina's over EPA Section 608 op epa.gov en in de studiehandleiding van je certificerende organisatie.

Zo bouwt StudyPDF volledige EPA 608-oefentoetsen uit je handleiding

Vijftien vragen kunnen laten zien welk deel nog wankel is. Ze dekken geen Universal-examen van 100 vragen, en een algemene vragenpool sluit zelden aan op de studiehandleiding die je certificerende organisatie je geeft.

StudyPDF werkt in plaats daarvan met jouw materiaal. Upload je EPA 608-studiehandleiding, de slides van je vakopleiding of foto's van je lesaantekeningen, tik op Nieuw materiaal, en StudyPDF bouwt oefenexamens uit precies die pagina's, ingedeeld zoals de echte test en aan het eind nagekeken. Elke vraag is geworteld in jouw materiaal en elke uitleg noemt waar het antwoord vandaan komt.

Je hebt geen document nodig om te beginnen. Noem gewoon een onderwerp, bijvoorbeeld terugwinnen bij Type III of de drie R's, en Bo zet het klaar met de kernbegrippen, zodat je er quizzen op kunt bouwen. Je resultaten houden bij welke begrippen je blijft missen, zodat de volgende quiz daarop kan mikken. Beginnen is gratis, en het gratis abonnement dekt ongeveer vier materialen per week.