- What does ODP stand for?
- Ozone Depletion Potential — how much a substance harms stratospheric ozone, relative to CFC-11 (1.0).
- What does GWP stand for?
- Global Warming Potential — how much heat a gas traps over time, relative to carbon dioxide (1.0).
- What does CFC stand for?
- Chlorofluorocarbon — an early refrigerant (e.g., R-12) with high ozone depletion potential.
- What does HCFC stand for?
- Hydrochlorofluorocarbon — a transitional refrigerant (e.g., R-22) with lower ODP than a CFC.
- What does HFC stand for?
- Hydrofluorocarbon — a chlorine-free refrigerant (e.g., R-410A) with zero ODP but high GWP.
- What does HFO stand for?
- Hydrofluoroolefin — a newer refrigerant (e.g., R-1234yf) with zero ODP and very low GWP.
- What law is Section 608 part of?
- The Clean Air Act — the U.S. federal law the EPA uses to regulate refrigerant handling.
- Is venting refrigerant legal?
- No. Knowingly venting refrigerant during service, repair, or disposal has been illegal since 1995.
- What is a de minimis release?
- A small, unavoidable release of refrigerant during good-faith recovery — not treated as illegal venting.
- What does 'recover' mean?
- Remove refrigerant from an appliance and store it in an external container, without cleaning or testing it.
- What does 'recycle' mean?
- Clean recovered refrigerant on-site (oil separation, filter-driers) for reuse in the same owner's equipment.
- What does 'reclaim' mean?
- Reprocess refrigerant to like-new purity meeting AHRI 700 and verify it chemically — the only refrigerant resold to a new owner.
- Which of the three R's can be resold to a new owner?
- Only reclaimed refrigerant — it must meet the AHRI 700 purity standard and be lab-verified.
- What purity standard must reclaimed refrigerant meet?
- AHRI 700 — the industry standard for like-new refrigerant purity.
- Who may legally buy regulated refrigerant?
- Only technicians certified under Section 608 (or 609 for motor-vehicle AC); the rule now covers most HFCs.
- Does EPA 608 certification expire?
- No — it is a one-time, lifetime credential with no renewal or CEUs required.
- Who administers the EPA 608 exam?
- EPA-approved certifying organizations (e.g., ESCO Institute, Mainstream Engineering, HVAC Excellence) — not the EPA itself.
- Where is the protective ozone layer located?
- In the stratosphere, well above the weather at ground level.
- What does stratospheric ozone protect us from?
- Harmful ultraviolet (UV) radiation from the sun.
- What health effects does ozone depletion increase?
- Higher rates of skin cancer and cataracts from increased ground-level UV radiation.
- Why can a leaked CFC damage ozone years later?
- It is so stable it drifts up to the stratosphere, where UV light eventually frees its chlorine.
- What frees chlorine from a CFC molecule?
- Ultraviolet (UV) light in the stratosphere splits the molecule and releases a chlorine atom.
- How does one chlorine atom harm ozone?
- It acts as a catalyst, destroying thousands of ozone molecules before it is removed.
- GWP is measured relative to which substance?
- Carbon dioxide (CO₂), which is set at a GWP of 1.0.
- ODP is measured relative to which substance?
- CFC-11, which is set at an ODP of 1.0.
- Can a refrigerant have zero ODP but high GWP?
- Yes — HFCs like R-410A do not deplete ozone but still trap a lot of heat (high GWP).
- What is the Montreal Protocol?
- The 1987 international treaty that set the schedule for phasing out ozone-depleting substances.
- When was the Montreal Protocol signed?
- 1987.
- Why were HCFCs phased out after CFCs?
- HCFCs were lower-ODP transitional refrigerants, so CFCs (the worst for ozone) were eliminated first.
- When did R-22 production and import end in the U.S.?
- January 1, 2020.
- How can a technician still get R-22 to service old equipment?
- By using recovered, recycled, or reclaimed R-22 from existing stock — no new R-22 is produced.
- What is the AIM Act?
- The American Innovation and Manufacturing Act of 2020, directing the EPA to phase down high-GWP HFCs.
- What does the AIM Act target — ozone or climate?
- Climate (GWP). HFCs have zero ODP, so the AIM Act phases them down for their warming potential.
- By how much does the AIM Act phase down HFCs?
- About 85% over 15 years.
- What is the single most important rule of Section 608?
- It is illegal to knowingly vent regulated refrigerant during service, maintenance, or disposal.
- Color of a refrigerant recovery cylinder?
- Gray body with a yellow top (shoulder).
- Maximum fill of a recovery cylinder?
- 80% of capacity by weight — liquid refrigerant expands as it warms and can rupture an overfilled cylinder.
- Why must a recovery cylinder never be filled past 80%?
- Liquid refrigerant expands as temperature rises; an overfilled cylinder can rupture.
- How often must a recovery cylinder be hydrostatically tested?
- Every 5 years (DOT requirement).
- Can disposable refrigerant cylinders be refilled?
- No — it is illegal to refill a disposable (one-time-use) cylinder.
- What must be done to a disposable cylinder before disposal?
- Evacuate it to a deep vacuum so it is empty before recycling the metal.
- What hazard does refrigerant vapor pose in a confined space?
- Asphyxiation — the vapor displaces oxygen; ventilate and use an oxygen-deprivation monitor.
- What injury can liquid refrigerant cause to skin or eyes?
- Frostbite — it is extremely cold; wear gloves and eye protection.
- What can happen if refrigerant contacts an open flame?
- It can form toxic gases (such as phosgene) — never expose refrigerant to a flame.
- What is a reclaimer?
- An EPA-certified facility that reprocesses used refrigerant to AHRI 700 purity for resale.
- What is a halogenated leak detector?
- An electronic detector that finds halogen-containing refrigerant leaks (CFCs, HCFCs, HFCs).
- What is the dielectric strength concern with refrigerants?
- Some refrigerants conduct or react in ways that matter for electrical safety; follow manufacturer handling rules.
- What recordkeeping is required when disposing of appliances?
- Records showing refrigerant was recovered before disposal must be kept per EPA requirements.
- Which Clean Air Act section covers motor-vehicle AC?
- Section 609 — Section 608 covers stationary equipment.
- What is a 'substitute' refrigerant under EPA rules?
- A non-ozone-depleting refrigerant (often an HFC or HFO) used in place of a CFC or HCFC.
- Does the venting prohibition cover HFCs?
- Yes — the prohibition was extended to most HFC substitute refrigerants, not just ozone-depleting ones.
- What is dehydration (evacuation) of a system?
- Pulling a deep vacuum to remove moisture and noncondensables before charging.
- What unit is used for deep-vacuum dehydration?
- Microns (1 micron = 0.001 mm Hg); about 500 microns is a typical deep-vacuum target.
- What instrument confirms a deep vacuum near 500 microns?
- A micron (vacuum) gauge.
- Why remove moisture from a refrigeration system?
- Moisture forms acids and ice, causing corrosion, restrictions, and component failure.
- What is an A2L refrigerant?
- A mildly flammable, low-toxicity refrigerant class (e.g., many HFOs) used as a low-GWP replacement.
- Why is R-410A's GWP a concern under the AIM Act?
- It has a high GWP, so it is being phased down even though it has zero ODP.
- What is virgin refrigerant?
- Newly manufactured refrigerant that has never been used, meeting purity specifications.
- What does 'self-contained' recovery equipment mean?
- Active recovery gear with its own compressor that can pull refrigerant from an appliance on its own.
- What does 'system-dependent' recovery mean?
- Passive recovery that uses the appliance's own compressor or pressure; allowed only on small appliances.
- What is the pressure-temperature (P/T) relationship?
- For a given refrigerant, pressure and saturation temperature change together — read with a P/T chart.
- Why must recovery equipment be certified?
- To prove it meets EPA performance standards for how much refrigerant it recovers.
- What is a major benefit of recovering refrigerant vs venting?
- It prevents ozone depletion and climate impact and conserves valuable refrigerant for reuse.
- What is a 'small appliance' under Section 608?
- A product fully manufactured, charged, and hermetically sealed at the factory with 5 lb or less of refrigerant.
- What charge size defines a small appliance?
- 5 pounds or less of refrigerant.
- Besides 5 lb, what makes a unit a small appliance?
- It must be fully manufactured, charged, and hermetically sealed at the factory.
- Is a field-charged unit a small appliance?
- No — a field-assembled or field-charged unit is never a small appliance, regardless of charge.
- Give examples of small appliances.
- Household refrigerators, freezers, window AC, PTACs, dehumidifiers, water coolers, and vending machines.
- Type I recovery: compressor running?
- Recover at least 90% of the charge (post-Nov 15 1993 equipment).
- Type I recovery: compressor not running?
- Recover at least 80% of the charge (post-Nov 15 1993 equipment).
- Why is the recovery target higher with the compressor running?
- A working compressor helps push refrigerant out, so more (90%) can be recovered.
- What date marks the higher recovery-equipment standards?
- November 15, 1993 — the cutoff for the higher post-1993 recovery efficiencies.
- Which equipment allows system-dependent (passive) recovery?
- Only small appliances.
- What is system-dependent recovery?
- Passive recovery using the appliance's own compressor or internal pressure to push refrigerant out.
- Can passive recovery be used on a large rooftop AC?
- No — system-dependent recovery is permitted only on small appliances.
- What is the recovery requirement if you don't know if the compressor works?
- Treat it as non-operating: recover at least 80% of the charge.
- Does Type I cover disposal of small appliances?
- Yes — Type I covers both servicing and disposal of small appliances.
- Is the Type I exam open-book?
- Through some EPA-approved organizations it can be taken open-book and proctored by mail.
- What is a piercing (saddle) valve used for on a small appliance?
- To access a sealed system for recovery; it taps into the line for the recovery device.
- What is a passive recovery device's main limitation?
- It depends on the appliance's own pressure/compressor, so it works only on small charges (small appliances).
- A small appliance has a seized compressor; you recover 82%. Compliant?
- Yes — 80% is the minimum when the compressor is inoperative.
- What refrigerants are common in small appliances?
- Historically R-12 and R-134a in refrigerators; R-600a (isobutane) in many newer units.
- What is R-600a?
- Isobutane — a low-GWP, mildly flammable hydrocarbon refrigerant used in many small appliances.
- Why handle hydrocarbon refrigerants (R-600a, R-290) carefully?
- They are flammable; follow special handling, charge limits, and ignition-source precautions.
- What is R-290?
- Propane — a flammable hydrocarbon refrigerant used in some self-contained small appliances.
- Must recovery equipment for small appliances be certified?
- Yes — it must meet the recovery standards for post-1993 small-appliance equipment.
- What is a packaged terminal air conditioner (PTAC)?
- A self-contained through-the-wall unit (hotels, apartments) that is typically a small appliance.
- What's the recovery rule for a household refrigerator with a running compressor?
- Recover at least 90% of the charge.
- What does Type II certification cover?
- High- and very high-pressure appliances — split AC, heat pumps, and supermarket refrigeration racks.
- Name common high-pressure (Type II) refrigerants.
- R-22, R-410A, R-404A, and R-407C.
- What is R-22?
- A high-pressure HCFC historically used in residential and commercial AC; production/import ended in 2020.
- What is R-410A?
- A very high-pressure HFC that replaced R-22 in modern AC and heat pumps; zero ODP, high GWP.
- How does R-410A's pressure compare to R-22's?
- R-410A operates at substantially higher pressures, so tools and recovery gear must be rated for it.
- What is R-404A typically used in?
- Commercial and supermarket refrigeration (a high-pressure HFC).
- Type II recovery level for a charge of 200 lb or less?
- 0 inches of mercury vacuum (atmospheric), with post-1993 equipment.
- Type II recovery level for a charge over 200 lb?
- 10 inches of mercury vacuum, with post-1993 equipment.
- What charge size changes the Type II recovery vacuum?
- 200 pounds — above it, the required vacuum increases (to 10 in. Hg with post-1993 gear).
- What unit are Type II recovery levels measured in?
- Inches of mercury (in. Hg) vacuum.
- At what charge do leak-repair requirements apply?
- Appliances containing 50 pounds or more of refrigerant.
- Leak-repair trigger for comfort-cooling appliances?
- An annual leak rate above 10%.
- Leak-repair trigger for commercial refrigeration?
- An annual leak rate above 20%.
- Leak-repair trigger for industrial process refrigeration?
- An annual leak rate above 30%.
- How soon must a triggering leak generally be repaired?
- Within 30 days of discovery (or follow an approved retrofit/retirement plan).
- What confirms a leak repair worked?
- A follow-up verification (leak) test confirming the leaks are fixed.
- Why do leak rules target large systems (50+ lb)?
- Large charges leaking at high rates release the most refrigerant, so repair is most beneficial.
- What recovery equipment do high-pressure systems require?
- Self-contained (active) recovery equipment — not passive recovery.
- What vacuum is used to dehydrate a high-pressure system?
- About 500 microns (a deep vacuum), measured with a micron gauge.
- Why dehydrate a system to ~500 microns?
- To remove moisture and noncondensables before recharging.
- What is superheat?
- The temperature of refrigerant vapor above its saturation temperature — used to check charge.
- What is subcooling?
- The temperature of liquid refrigerant below its saturation temperature — used to check charge.
- What is R-407C used for?
- As an R-22 retrofit replacement refrigerant (a high-pressure HFC blend).
- Why can't you use R-22 gauges on R-410A?
- R-410A's higher operating pressure requires gauges and equipment rated for those pressures.
- What is a high-pressure cutout switch?
- A safety control that shuts the system down if discharge pressure rises too high.
- Which Type II number pair matters most for recovery?
- 200 lb charge cutoff and 0 vs 10 in. Hg vacuum (≤200 lb vs >200 lb, post-1993).
- What is a 'very high-pressure' appliance?
- Equipment using refrigerants like R-410A or R-13 that operate at especially high pressures (covered by Type II).
- Can an HFC system trigger leak-repair requirements?
- Yes — leak-repair requirements have been extended to substitute refrigerants such as HFCs.
- What does Type III certification cover?
- Low-pressure appliances — centrifugal chillers that operate under a vacuum.
- What defines a low-pressure appliance?
- It uses a refrigerant that boils below atmospheric pressure, so the low side runs under a vacuum.
- Name common low-pressure (Type III) refrigerants.
- R-11 and R-123 (HCFCs), and R-1233zd (a low-GWP HFO replacement).
- What is R-11?
- The traditional low-pressure refrigerant in older centrifugal chillers; a CFC, now phased out.
- What is R-123?
- The HCFC replacement for R-11 in low-pressure chillers; lower ODP but more toxic.
- What is R-1233zd?
- A near-zero-ODP, very-low-GWP HFO refrigerant used in newer low-pressure chillers.
- Type III recovery level (post-1993 equipment)?
- 25 mm Hg absolute.
- What does 'mm Hg absolute' mean?
- A pressure measured from a perfect vacuum — not a reading on a standard vacuum gauge.
- Why is Type III recovery given as 'absolute' not 'vacuum'?
- Low-pressure systems run under a vacuum, so the target is set from a perfect vacuum (25 mm Hg absolute).
- In a low-pressure chiller, do leaks let refrigerant out or air in?
- Air and moisture leak IN, because the low side operates below atmospheric pressure.
- Why does air leak into a low-pressure chiller?
- Its low side is below atmospheric pressure, so higher outside pressure pushes air inward.
- What are noncondensables?
- Gases like air and nitrogen that don't condense; they raise condensing pressure and cut efficiency.
- What does a purge unit do?
- Removes air and noncondensable gases from a low-pressure chiller while retaining the refrigerant.
- What does excessive purging indicate?
- An air leak letting noncondensables into the system — find and fix it.
- Why are high-efficiency purge units preferred?
- They release far less refrigerant per unit of air purged than older designs.
- What protects a low-pressure chiller vessel from over-pressure?
- A rupture disc, typically set around 15 psig.
- At about what pressure does a low-pressure rupture disc relieve?
- Around 15 psig.
- What gas is used to leak-test a low-pressure system?
- Dry nitrogen — inert, so it won't form a combustible mixture with the oil.
- Why not use oxygen to pressurize a low-pressure system?
- Oxygen can combine with refrigeration oil to form a combustible/explosive mixture.
- Why not pressurize a low-pressure chiller to 30 psig?
- It exceeds the ~15 psig rupture disc and would burst the disc.
- Between R-11 and R-123, which has lower ODP?
- R-123 has the lower ozone depletion potential.
- What's the safety trade-off with R-123?
- Lower ODP than R-11, but higher toxicity — needs ventilation and exposure monitoring.
- What happens when air accumulates in a low-pressure chiller?
- It raises condensing pressure and reduces system efficiency.
- What kind of compressor do low-pressure chillers use?
- A centrifugal compressor.
- What recovery equipment do low-pressure appliances require?
- Self-contained (active) recovery equipment designed for low-pressure work.
- What is ozone (chemical formula)?
- O₃ — a molecule of three oxygen atoms that, in the stratosphere, absorbs UV radiation.
- What is the troposphere?
- The lowest atmospheric layer where weather occurs; ground-level ozone here is a pollutant, not protective.
- Why is ground-level ozone different from stratospheric ozone?
- Ground-level ozone is smog (harmful to breathe); stratospheric ozone shields Earth from UV.
- What is R-12?
- A common CFC refrigerant (high ODP) once used in refrigerators and car AC; now banned from production.
- What is R-134a?
- An HFC refrigerant (zero ODP, high GWP) widely used in refrigeration and older mobile AC.
- What is a blend (zeotropic) refrigerant?
- A mix of refrigerants whose components boil at different temperatures, causing temperature glide.
- What is temperature glide?
- The temperature range over which a zeotropic blend evaporates or condenses; charge as a liquid.
- Why charge a zeotropic blend as a liquid?
- To keep the blend's proportions correct; charging as vapor can fractionate the components.
- What is fractionation of a refrigerant blend?
- Separation of a blend's components so the mix no longer matches its spec — avoid by liquid charging.
- What agency enforces Section 608?
- The U.S. Environmental Protection Agency (EPA).
- Can you be fined for venting refrigerant?
- Yes — illegal venting can result in significant civil penalties under the Clean Air Act.
- What is an EPA-certified recovery machine?
- Equipment tested and certified to meet EPA recovery performance standards.
- What is the difference between a CFC and an HCFC?
- An HCFC contains hydrogen, making it less stable and lower-ODP than a CFC.
- Why does adding hydrogen lower a refrigerant's ODP?
- The hydrogen makes the molecule break down lower in the atmosphere, so less chlorine reaches the ozone layer.
- What is the Significant New Alternatives Policy (SNAP)?
- An EPA program that reviews and lists acceptable substitute refrigerants.
- What does it mean if a refrigerant is 'phased out'?
- Its production and import are banned on a schedule (e.g., CFCs, then HCFCs).
- What does it mean if a refrigerant is 'phased down'?
- Its production/consumption is reduced over time but not fully banned — e.g., HFCs under the AIM Act.
- What PPE protects against liquid-refrigerant frostbite?
- Gloves and eye protection (safety glasses or goggles).
- What monitor warns of an oxygen-deficient atmosphere?
- An oxygen-deprivation (oxygen) monitor.
- What is a deep vacuum used for besides dehydration?
- To verify a system holds vacuum (a leak/standing-vacuum test) and to remove noncondensables.
- What does 'hermetically sealed' mean?
- Factory-sealed so the refrigerant circuit is airtight and closed.
- What is an overfill-protection device on a cylinder?
- A float or shutoff that prevents filling a recovery cylinder past the safe 80% level.
- Why keep records of recovered refrigerant?
- EPA requires recordkeeping to verify proper recovery, recycling, reclamation, and disposal.
- What's the purpose of a filter-drier in recycling?
- To remove moisture and contaminants from refrigerant during on-site recycling.
- What is the main goal of the three R's?
- To keep refrigerant out of the atmosphere by reusing it rather than venting and replacing it.
- Why is a window AC a small appliance but a split AC isn't?
- The window unit is factory-sealed and charged; the split system is field-assembled and field-charged.
- What is the recovery requirement label '90/80' shorthand for?
- 90% recovery with the compressor running, 80% with it not running (small appliances).
- Can a vending machine be a small appliance?
- Yes — if it's factory-sealed with 5 lb or less of refrigerant.
- Is a dehumidifier a small appliance?
- Yes — typically factory-sealed with a small charge.
- What tool accesses a sealed small-appliance system?
- A piercing/saddle (line-tap) valve to connect the recovery device.
- Does Type I allow active (self-contained) recovery too?
- Yes — you may use self-contained equipment on small appliances; passive is also allowed only here.
- If a small-appliance compressor works, what % must you recover?
- At least 90% of the charge.
- If a small-appliance compressor is dead, what % must you recover?
- At least 80% of the charge.
- Why might you recover less when the compressor is off?
- Without the compressor's help, the standard is set lower (80%).
- What's a key flammable-refrigerant precaution for small appliances?
- Control ignition sources and follow charge limits for R-600a/R-290 hydrocarbon refrigerants.
- What is a split-system air conditioner?
- A field-installed AC with separate indoor and outdoor units — a Type II high-pressure appliance.
- What is a heat pump?
- A reversible AC that heats or cools; high-pressure equipment under Type II.
- Why must a 250-lb system be recovered deeper than a 150-lb one?
- Over 200 lb the required vacuum increases (to 10 in. Hg with post-1993 gear).
- Is a 150-lb high-pressure system recovered to 0 or 10 in. Hg?
- 0 in. Hg — it is at or below the 200-lb cutoff.
- Is a 250-lb high-pressure system recovered to 0 or 10 in. Hg?
- 10 in. Hg vacuum — it is above the 200-lb cutoff (post-1993 gear).
- Does a 60-lb leaking comfort-cooling system trigger repair?
- Yes if it exceeds the 10% annual leak rate (it's over the 50-lb threshold).
- Does a 30-lb system fall under the leak-repair rule?
- No — leak-repair requirements apply at 50 lb or more.
- What's the recordkeeping after a major leak repair?
- Document the leak rate, repair, and the follow-up verification test.
- Why is R-410A called a 'very high-pressure' refrigerant?
- It operates at notably higher pressures than R-22, requiring higher-rated equipment.
- What is a micron gauge used for on a high-pressure system?
- To confirm a deep evacuation (about 500 microns) during dehydration.
- What is a P/T (pressure-temperature) chart used for?
- To find a refrigerant's saturation temperature at a given pressure when checking charge.
- What is a recovery-only vs recovery/recycle machine?
- Recovery-only just removes refrigerant; a recovery/recycle machine also cleans it on-site.
- What is a centrifugal chiller?
- A large cooling machine using a centrifugal compressor — typically a low-pressure (Type III) appliance.
- Why is R-11 considered low-pressure?
- It boils below atmospheric pressure, so the system operates under a vacuum at normal temperatures.
- How do you identify a low-pressure appliance in the field?
- Its low side sits in a vacuum during operation (below atmospheric pressure).
- What's the leak concern unique to low-pressure chillers?
- Air and moisture leaking IN (not refrigerant leaking out), because of the internal vacuum.
- What pressure unit identifies a Type III recovery question?
- 'mm Hg absolute' (25 mm Hg) — distinct from Type II's inches of mercury vacuum.
- What's the effect of noncondensables on a chiller?
- They raise condensing pressure and lower efficiency.
- What signals an air leak on a low-pressure chiller?
- A purge unit running far more frequently than normal.
- Why pressurize with nitrogen below 15 psig when leak-testing?
- To stay under the rupture-disc setting and avoid bursting the disc.
- Compared with R-11, is R-123 more or less toxic?
- More toxic — it requires greater attention to ventilation and exposure monitoring.
- What replaces R-11/R-123 with near-zero environmental impact?
- R-1233zd, a low-GWP, near-zero-ODP HFO.
- What does a rupture disc on a chiller do?
- Relieves excess pressure (around 15 psig) to protect the vessel from rupturing.
- Why is oxygen dangerous for pressurizing a chiller?
- It can react with the refrigeration oil to form a combustible or explosive mixture.