⚡ EPA 608 Universal — Fast-Track Study App

Ozone, the science & the law

• Chlorine (from CFCs/HCFCs) is what destroys stratospheric ozone; one chlorine atom destroys thousands of ozone molecules. ODP = Ozone Depletion Potential (CFC-12 = 1.0 reference). GWP = Global Warming Potential.
• CFCs (R-11, R-12, R-502) = highest ODP; HCFCs (R-22, R-123) = lower ODP; HFCs (R-410A, R-134a) = zero ODP but have GWP.
• Montreal Protocol = the international treaty that phased out ozone-depleters. Clean Air Act Section 608 = the U.S. law making venting illegal and requiring certification.
• Phaseouts: CFC production ended 1995; HCFC-22 (R-22) production & import ended Jan 1, 2020 (only reclaimed/recycled R-22 now). HFCs are now being phased down under the AIM Act.

It is illegal to vent

• Knowingly venting CFC, HCFC, and HFC refrigerants during service/repair/disposal is illegal (since 1995 for ODS; extended to HFC substitutes).
• De minimis releases during good-faith service, and releases of certain non-ozone, non-exempt gases, are the only exceptions.
• EPA can fine up to ~$59,000+ per day, per violation (the figure rises with inflation; older guides say $37,500 or $25,000 — any "large daily fine" answer is the intent). A reward is offered for reporting violators.

The 3 R's

Recovery equipment & cylinders

• Self-contained (active): recovery unit has its own pump/compressor — pulls refrigerant out itself. System-dependent (passive): relies on the appliance's own compressor/pressure (used on small appliances only).
• Liquid recovery is faster than vapor recovery. Recover liquid first, then vapor.
• Use a DOT-approved recovery cylinder — gray body, yellow top/shoulder. Never fill past 80% of capacity (liquid expands with heat → hydrostatic rupture).
• Don't mix refrigerants in one cylinder — mixed refrigerant can't be reclaimed and must be destroyed. Check the cylinder's tare weight.
• A recovery cylinder must be evacuated before its first use and refrigerant identified before recovery.

Required recovery / evacuation levels memorize

Before opening a system for major repair, you must pull it down to these vacuum levels (deeper for newer equipment):

"in Hg" = inches of mercury vacuum. Low-pressure's 25 mm Hg absolute (≈ 29 in Hg) is the most-tested number — know it.

Leak repair (appliances > 50 lb charge)

• Owners must repair leaks when the annual leak rate exceeds: Comfort cooling 10% · Commercial refrigeration 20% · Industrial process 30%. (Older exam versions use 15% comfort / 35% commercial-industrial — pick the "must repair" answer.)
• Leaks generally must be repaired within 30 days.
• Appliances < 50 lb are not subject to the leak-repair trigger, but you still can't vent.

Safety

• Refrigerant displaces oxygen → asphyxiation risk in low/enclosed spaces. Liquid contact → frostbite. Always wear safety glasses + gloves.
• Refrigerant near an open flame/hot surface → forms phosgene (toxic) and other acids. Don't smoke around it.
• Never use oxygen or compressed air with refrigerant to pressure-test/clear lines — explosion risk. Use dry nitrogen (with a regulator).
• ASHRAE Standard 15 = mechanical-room safety; Standard 34 = refrigerant safety classification (toxicity A/B, flammability 1/2/3).
• The last person in the disposal chain (e.g., scrap/recycler of a fridge) is responsible for ensuring refrigerant was recovered.

What counts as a "small appliance"

• ≤ 5 lb of refrigerant, hermetically sealed, and factory-charged: refrigerators, freezers, window/room A/C, water coolers, dehumidifiers, vending machines, PTACs.

Recovery requirements memorize

Trick they test: if the compressor doesn't run, you can only require 80%.

Equipment & refrigerants

• High-pressure systems > 5 lb that aren't small appliances or low-pressure: residential/commercial split A/C, heat pumps, supermarket racks, process refrigeration.
• Refrigerants: R-22, R-410A, R-407C, R-404A, R-134a, R-502. Very high-pressure: R-13, R-503, R-23.
• R-410A runs at much higher pressure than R-22 — needs gauges/recovery rated for it; it's a near-azeotrope HFC (zero ODP).

Recovery & evacuation

• Same EPA evacuation table as Core: high-pressure ≥200 lb → 10 in Hg (post-'93); <200 lb → 0 in Hg.
• Recover liquid first, then vapor. Don't fill recovery cylinder past 80%.
• If non-condensables (air) collect at the top of the condenser/cylinder, head pressure reads high — purge or recover/clean.

Leak detection methods

• Electronic leak detector — most sensitive for small leaks.
• Soap bubbles — cheap, good for pinpointing once you're close.
• Fluorescent UV dye + black light — finds slow/intermittent leaks.
• Halide torch — older method; flame turns green near a halogenated leak (rarely the "best" answer today).
• Pressure-test/standing-pressure test with dry nitrogen (never oxygen).
• Refrigerant migration: during off-cycle, refrigerant migrates to the coldest part (often the compressor crankcase) — a crankcase heater prevents it.

What they are

• Low-pressure = boils below atmospheric pressure; operates in a vacuum. These are centrifugal chillers.
• Refrigerants: R-11, R-123, R-113 (and newer R-1233zd). R-11 (CFC, ODP 1.0) is gone; R-123 (HCFC) is the common replacement, B1-class (low flammability, higher toxicity).

The numbers that get tested memorize

Why 10 psig max? Because the rupture disk lets go at 15 psig — go higher and you blow the disk (and lose your charge).

Numbers to memorize

Refrigerant quick-ID

The difference in one line each

Recovering: methods & how to choose

• Active (self-contained): the recovery machine has its own compressor and does the work. Required on anything with more than 15 lb of charge.
• Passive (system-dependent): uses the appliance's own compressor/pressure — small appliances only.
• Vapor recovery: pulls refrigerant as a gas — slower, but all you can do on small charges.
• Liquid recovery: faster; remove liquid first, then switch to vapor to finish.
• Push-pull: for large liquid charges — vapor pressure pushes liquid out one port while the machine pulls from another. Fastest method for big systems; don't use it on small charges.
• Manufacturers must provide service ports or a stub for an access valve. On sealed systems with no port, add a piercing/saddle valve (temporary — they leak long-term).

AHRI refrigerant classes (sizing your recovery equipment)

Recovery/recycling equipment is rated by the AHRI class of refrigerant it can handle. Know which class you're working with:

Your recovery machine must be rated for the class of refrigerant you're removing.

Recovery-cylinder discipline (where techs get fined)

• Use a DOT-approved, refillable recovery cylinder — gray body, yellow top. Never refill a disposable cylinder.
• Never fill past 80% by weight. Use a scale and the cylinder's tare weight; liquid expands with heat and can rupture an overfilled cylinder.
• Evacuate a new/empty recovery cylinder before first use to remove air and moisture.
• Identify the refrigerant before you recover. Don't recover an unknown into a partly-used cylinder — mixed refrigerants can't be reclaimed and must be destroyed.
• Don't store/transport cylinders above ~125°F; secure them upright with the valve protected.

Recycling: what it does (and doesn't)

• Recycling reduces contaminants on-site — it separates oil and passes refrigerant through filter-driers to cut moisture, acid, and particulate.
• It does not verify the refrigerant meets new-product spec, so recycled refrigerant may only go back into the same owner's equipment.
• "Single-pass" cleans once during recovery; "multi-pass" recirculates for cleaner results. Recovery/recycle equipment should be certified to AHRI Standard 740.

Reclaiming: the only path to resale

• Reclaimed refrigerant is reprocessed and laboratory-tested to AHRI Standard 700 (the new-product purity spec).
• It must be done by an EPA-certified reclaimer — EPA publishes the list of certified reclaimers.
• Reclaiming is the only way refrigerant may be sold or transferred to a different owner. With R-22 no longer produced, reclaimed R-22 is now the main legal supply for older systems.

Most-missed points

• Recycle ≠ reclaim. Only reclaimed (AHRI 700) refrigerant can change owners.
• Passive recovery is banned over 15 lb — use an active machine.
• Mixed/cross-contaminated refrigerant is a total loss — it can't be reclaimed.
• Disposable cylinders are single-use; refilling them is illegal and dangerous.