HVAC: EPA 608 Tech Cert practice questions and exam guide

Which is the correct meaning of 'global warming potential' (GWP)?

1. Energy use of a unit per ton of cooling
2. Total emissions of a unit over its life
3. Direct chemical attack on stratospheric ozone
4. Heat-trapping effect of 1 kg of a gas over 100 years relative to 1 kg of CO2

Answer: D — Heat-trapping effect of 1 kg of a gas over 100 years relative to 1 kg of CO2

A) That is COP or efficiency. D) Correct — GWP is a 100-year relative metric vs CO2 (CO2 = 1). C) That is ODP. B) That is TEWI, a separate index that combines direct and indirect effects.

Which of the following is a recognized exception to the prohibition on venting?

1. Releasing refrigerant from a system that is being scrapped anyway
2. Releasing refrigerant from a cylinder whose contents cannot be identified
3. Releasing refrigerant outdoors where it will disperse quickly
4. Releasing nitrogen used to pressure test a system that holds no refrigerant

Answer: D — Releasing nitrogen used to pressure test a system that holds no refrigerant

D) Correct — nitrogen is not a regulated refrigerant, so purging it from an evacuated system is not venting. A) is a common excuse, but disposal is exactly when recovery is required. C) treats dispersal as harmless, which the rule flatly rejects. B) is wrong because unknown refrigerant must still be recovered and handled as waste, never released.

GWP stands for:

1. Global Wattage Power
2. Global Warming Potential
3. Gas Weight Pressure
4. General Working Pressure

Answer: B — Global Warming Potential

A/C/D) Not industry terms. B) Correct — GWP measures heat-trapping ability vs CO₂ (CO₂=1). HFCs have high GWP; HFOs are low-GWP alternatives.

An AHRI 700-certified reclaimer is required because:

1. OSHA mandates third-party purity testing
2. UL listing of recovery machines depends on it
3. DOT requires reclaimers to be licensed transportation companies
4. Refrigerant offered for sale as reclaimed must meet a chemical purity spec verified by lab analysis

Answer: D — Refrigerant offered for sale as reclaimed must meet a chemical purity spec verified by lab analysis

A) OSHA does not set this. D) Correct — AHRI 700 is the chemical purity standard; reclaim status requires lab verification at an EPA-certified reclaimer. C) DOT covers transport, not chemistry. B) UL listing is unrelated.

A small appliance is brought in with a burned out compressor. Which recovery approach is appropriate?

1. System-dependent recovery, since the appliance is small
2. No recovery is needed because the compressor cannot run
3. Self-contained recovery, since the compressor cannot run
4. Recycling equipment, since burnout contaminates the charge

Answer: C — Self-contained recovery, since the compressor cannot run

C) Correct — with a dead compressor the recovery machine must supply its own pumping, which is what self-contained equipment does. A) fails precisely because system-dependent methods need a working compressor. B) is a venting violation dressed up as a technicality. D) tempts because burnout does contaminate the charge, but the question is how to get the refrigerant out, and burnt refrigerant should go for reclamation rather than field recycling.

A recovery cylinder must not be filled above what percentage of its capacity?

1. 50%
2. 65%
3. 80%
4. 100%

Answer: C — 80%

A/B) Wasteful. C) Correct — 80% maximum fill leaves 20% headspace for thermal expansion of liquid refrigerant. D) Overfilling risks rupture from expansion.

Liquid refrigerant contacting bare skin presents which PRIMARY hazard?

1. Chemical burns from acid formation in the oil
2. Frostbite from rapid evaporative cooling of the skin
3. Absorption into the bloodstream through the skin
4. Radiation burns from ultraviolet exposure

Answer: B — Frostbite from rapid evaporative cooling of the skin

B) Correct — liquid refrigerant flashes to vapor and pulls heat from the skin, producing freeze injury. A) tempts because acids do form inside burned-out systems, but the immediate contact hazard is cold. C) is not the main route of harm; inhalation matters far more than skin absorption. D) is unrelated to refrigerant handling.

Before entering a machinery room after an alarm, the technician should rely MOST on:

1. The absence of any noticeable refrigerant odor
2. A quick visual scan for frost on the piping runs
3. An oxygen or refrigerant monitor reading plus ventilation
4. The chiller's own control panel fault history

Answer: C — An oxygen or refrigerant monitor reading plus ventilation

C) Correct — instrument readings and purge ventilation establish that the atmosphere is safe, since the hazard is not reliably detectable by the senses. A) is dangerous; many refrigerants have little warning odor at hazardous concentrations. B) may confirm a leak but cannot confirm the air is breathable. D) tells you about the machine, not the room atmosphere.

A technician suspects a very small leak on a brazed joint but the electronic detector alarms erratically near the compressor. What is the BEST next step?

1. Declare the joint sound and move on to the next unit
2. Add fluorescent dye and inspect the joint immediately
3. Increase detector sensitivity and re-scan without ventilating
4. Confirm the suspect area with bubble solution after ventilating it

Answer: D — Confirm the suspect area with bubble solution after ventilating it

D) Correct — electronic detectors false alarm around residual vapor and oils, so clearing the area and confirming with bubbles pinpoints the leak. A) ignores an unresolved indication. C) makes the false alarms worse rather than resolving them. B) tempts because dye is a good method, but it needs run time to circulate and show at the leak.

Before filling a recovery cylinder that has been sitting in a shop for several years, the technician should FIRST check which item?

1. That the cylinder still holds a slight positive pressure
2. That the cylinder's requalification date has not lapsed
3. That the paint on the cylinder shoulder is still bright
4. That the cylinder weighs less than its stamped tare weight

Answer: B — That the cylinder's requalification date has not lapsed

B) Correct — a cylinder must be within its periodic hydrostatic requalification interval before it may be filled or offered for transport. A) is a useful check for contamination but does not make an out-of-date cylinder legal. C) mistakes cosmetic condition for certification status. D) is impossible; a cylinder cannot weigh less than its own empty weight, and weight checks address fill level, not requalification.

After Nov 14, 1994, who can purchase regulated refrigerants?

1. Anyone
2. Only EPA-certified technicians (or certain entities)
3. Only contractors
4. Only equipment owners

Answer: B — Only EPA-certified technicians (or certain entities)

A) Public can't buy. B) Correct — EPA Section 608 cert required for purchase of most regulated refrigerants. C) Cert needed in addition. D) Owners typically can't buy regulated refrigerant directly.

A technician disposes of a residential refrigerator at a scrap yard. What documentation practice applies?

1. A signed statement verifying refrigerant was recovered before disposal
2. A DOT shipping paper covering the sealed appliance as a hazard class
3. An EPA-issued serial number assigned to the recovered charge
4. A reclaimer's purity certificate for the refrigerant left in the unit

Answer: A — A signed statement verifying refrigerant was recovered before disposal

A) Correct — the party who takes final custody must verify and document that the refrigerant was removed before the appliance was scrapped. B) misapplies cylinder shipping rules to a sealed appliance. C) invents a tracking number that does not exist. D) confuses reclamation certification with disposal verification, and no charge should remain in the unit at all.

Using system-dependent recovery on a refrigerator with a dead compressor, what BEST improves refrigerant migration into the recovery bag or cylinder?

1. Warming the appliance while chilling the recovery cylinder
2. Restricting the process tube to slow the transfer rate
3. Adding nitrogen pressure to the appliance to push refrigerant out
4. Running the appliance's condenser fan at high speed continuously

Answer: A — Warming the appliance while chilling the recovery cylinder

A) Correct — passive recovery depends on a pressure difference, so warming the appliance and cooling the receiving vessel drives refrigerant in the desired direction. B) slows the job without improving the driving force. C) contaminates the recovered refrigerant with a non-condensable, which is prohibited practice. D) cools the condenser and works against the needed pressure difference.

Which refrigerant has been broadly approved under EPA's SNAP rule for new domestic refrigerators with strict charge limits?

1. R-22
2. R-410A
3. R-600a (isobutane)
4. R-123

Answer: C — R-600a (isobutane)

A) Phased out. B) Used in residential AC, not domestic refrigerators. C) Correct — SNAP listed R-600a for domestic refrigerator/freezer applications with charge size and equipment safety limits. D) R-123 is a low-pressure chiller refrigerant.

When working on an R-600a domestic refrigerator with a hydrocarbon charge, the technician must:

1. Use a standard halogen leak detector
2. Use an open-flame torch to test for leaks
3. Use an A3-compatible leak detector and follow ignition-source controls per OEM service instructions
4. Treat it identically to an R-134a refrigerator

Answer: C — Use an A3-compatible leak detector and follow ignition-source controls per OEM service instructions

A) Halide detectors do not see hydrocarbons. B) Open flame ignites A3. C) Correct — combustible-gas detector, sparkless tools, and OEM procedures are required for R-600a. D) Different procedures required because of flammability.

Which is a Type II EPA 608 certification covered system?

1. Refrigerator
2. Window AC
3. Residential central AC
4. Large industrial chiller below atmospheric pressure

Answer: C — Residential central AC

A/B) Type I (small appliance). C) Correct — Type II = high-pressure systems including residential central AC + supermarket refrigeration. D) That's Type III (low-pressure).

A technician measures suction line temperature and compares it to the saturation temperature for the suction pressure. That comparison yields:

1. Subcooling, which confirms liquid at the condenser exit
2. The compression ratio developed across the compressor
3. The system's total heat of rejection at the condenser
4. Superheat, which confirms no liquid is returning to the compressor

Answer: D — Superheat, which confirms no liquid is returning to the compressor

D) Correct — superheat is measured on the low side and tells you the refrigerant has fully boiled before reaching the compressor. A) is the mirror-image measurement taken on the liquid line and is the most common mix-up on this topic. B) is a pressure ratio, not a temperature comparison. C) is a capacity calculation, not a field measurement of this kind.

A technician is certified for Type II work. Which appliance falls squarely within that scope?

1. A centrifugal chiller operating below atmospheric pressure
2. A hermetically sealed dehumidifier with a small charge
3. A vending machine with a factory charge under five pounds
4. A supermarket refrigeration rack system using R-404A

Answer: D — A supermarket refrigeration rack system using R-404A

D) Correct — high-pressure commercial refrigeration is Type II work. A) is a low-pressure machine and requires Type III. B) and C) are both small appliances at or below the five-pound threshold and fall under Type I; applying Type II scope to them is the classic category mix-up.

R-123 production for servicing existing US chillers is being phased down because:

1. It is highly toxic
2. It is an HCFC under the Montreal Protocol HCFC schedule (production for service ends 2030)
3. It is flammable
4. It is an HFC under AIM Act

Answer: B — It is an HCFC under the Montreal Protocol HCFC schedule (production for service ends 2030)

A) B1 class — toxicity managed by ASHRAE 15 ventilation. B) Correct — HCFC schedule allows R-123 service-use production through 2030; new equipment ban earlier. C) Non-flammable. D) Not an HFC.

An open-drive centrifugal chiller's shaft seal:

1. Has no maintenance requirement
2. Is a common refrigerant leak point and must be inspected per OEM intervals
3. Cannot leak by design
4. Is regulated only by OSHA

Answer: B — Is a common refrigerant leak point and must be inspected per OEM intervals

A) Seals wear. B) Correct — shaft seals on open-drive units leak slowly; routine inspection and seal replacement are part of EPA leak management. C) Mechanical wear permits leakage. D) EPA leak repair rules apply.

A 'low edge' pressure transducer on a centrifugal chiller helps detect:

1. Surge (reversal of flow at very low load)
2. Compressor amp draw
3. Tower water flow only
4. Oil sump heater status

Answer: A — Surge (reversal of flow at very low load)

A) Correct — surge protection logic uses suction/discharge differentials and motor signals to identify impending surge. B) Amps are sensed elsewhere. C) Flow sensors handle water. D) Sump heater is a separate control.

Refrigerant Management Rule under the AIM Act focuses on:

1. Reclamation, leak repair, and disposal of HFCs and HFC substitutes
2. Stratospheric ozone monitoring
3. Tax credits for new equipment
4. Worker pay rates

Answer: A — Reclamation, leak repair, and disposal of HFCs and HFC substitutes

A) Correct — refrigerant management requires reclaim infrastructure, lifecycle tracking, leak repair, and disposal; extends 608-style rules to HFCs. B) Ozone is Montreal Protocol scope. C) Not part of the rule. D) Out of scope.

The HFC phasedown under the AIM Act is administered mainly through which mechanism?

1. An outright ban on HFC imports beginning immediately
2. A declining allowance system for producers and importers
3. A tax collected at the point of retail sale
4. Mandatory retirement of all existing HFC equipment

Answer: B — A declining allowance system for producers and importers

B) Correct — EPA issues and progressively reduces allowances that producers and importers must hold. A) overstates the approach; the phasedown is stepwise rather than an immediate ban. C) invents a tax mechanism that the statute does not use. D) is false, since existing equipment may continue to operate and be serviced.

EPA's leak repair rule for HFC-containing appliances was finalized under:

1. Section 609
2. Subpart F of 40 CFR Part 84 (AIM Act Refrigerant Management Rule) extending leak-repair concepts to HFCs
3. RCRA
4. OSHA Process Safety Management

Answer: B — Subpart F of 40 CFR Part 84 (AIM Act Refrigerant Management Rule) extending leak-repair concepts to HFCs

A) Section 609 is MVAC. B) Correct — EPA extended leak-repair, recordkeeping, and verification rules to HFCs through the AIM Act refrigerant management rules. C) RCRA is hazardous waste. D) PSM is for highly hazardous chemicals like ammonia.

Disposal of small appliances — who's responsible?

Last person in the disposal chain — usually the scrap recycler. Recovery before disposal required.

What defines a low-pressure refrigerant, and name two examples.

One with a boiling point above about 10 degrees C that operates in a vacuum on the low side at normal temperatures. Examples: R-11, R-123 and R-113.

What is EPA's definition of a small appliance?

A product manufactured, charged and hermetically sealed in a factory with 5 pounds or less of refrigerant — for example household refrigerators and freezers, room air conditioners, water coolers and vending machines.

Recovery cylinder color?

Gray with yellow shoulders (DOT spec). Not refillable disposable cylinders.

Define recovery, recycling and reclamation as the three Rs of refrigerant handling.

Recovery is removing refrigerant from an appliance and storing it in an external container without testing or processing it • Recycling reduces contaminants on site by oil separation and filter-drying • Reclamation reprocesses refrigerant to the AHRI 700 purity specification and requires chemical analysis to verify it.

What defines a high-pressure refrigerant, and name three common examples.

A refrigerant with a boiling point roughly between minus 50 and 10 degrees C that operates above atmospheric pressure throughout the system. Examples: R-22, R-410A, R-134a, R-404A and R-407C.