EPA 608 Type II key terms

The amount of refrigerant an appliance loses over twelve months, usually stated as a percentage of the full charge. EPA uses the leak rate to decide when repairs and follow-up verification are required.

A portable instrument with a heated sensor or infrared cell that senses refrigerant vapor in the surrounding air and signals with sound or light. Sensitivity is rated in ounces per year, so it is checked against a reference leak.

Brushing soap solution or a commercial bubble liquid onto a joint and watching for bubbles that show escaping gas. It confirms the exact location of a leak but cannot measure how large the leak is.

Isolating a circuit, charging it with dry nitrogen to a safe pressure, and watching an accurate gauge for a drop over time. It locates leaks without releasing refrigerant into the atmosphere.

Evacuating a system, valving off the pump, and watching the micron gauge. A vacuum that climbs steadily toward atmospheric pressure means air is entering, indicating a leak or trapped moisture.

A flame-type detector that changes color when halogenated refrigerant is drawn into its air intake. It is not used with HFCs because the flame can create toxic gases, and it is largely obsolete.

Removing refrigerant from an appliance and storing it in an approved external cylinder without any cleaning or processing. Recovery is required before opening a system and comes before recycling or reclaiming.

Refrigerant taken out of an appliance and stored in a cylinder. It may carry oil, moisture, acid, and other impurities, so it is not automatically clean enough to be used in another system.

A refillable, DOT-approved pressure vessel commonly gray with a yellow shoulder, used only for recovered refrigerant. It must have a current test date and be filled by weight or with a float-limited valve.

A transfer technique in which the recovery machine pulls vapor from the top of the appliance and pushes condensed liquid out of the bottom into the cylinder. It is fast for large charges but needs a sight glass.

Drawing refrigerant from the liquid line or receiver so mostly liquid enters the recovery cylinder. It moves a charge quickly but requires care to avoid hydraulically locking the recovery machine.

Drawing refrigerant gas from the suction side of a system into a recovery machine. It is slower than liquid recovery and is used mainly to pull the last of the charge out of an appliance.

A compressor-driven device built to move refrigerant from an appliance into a recovery cylinder. It must be rated for the refrigerant's pressure class, and incompatible refrigerants must never be mixed in it.

The minimum portion of a high-pressure appliance's charge that recovery equipment must remove: at least 80 percent from units built before November 15, 1993 and at least 90 percent from later units, or evacuation to the specified vacuum level.

Cleaning recovered refrigerant on site by passing it through filter-driers and oil separators to remove moisture, acid, and particles. Recycled refrigerant may be returned only to equipment owned by the same person.

Refrigerant reprocessed at a facility to meet AHRI 700 purity limits, verified by laboratory analysis and labeled as reclaimed. Only reclaimed refrigerant may be sold or moved to equipment owned by someone else.

The industry specification listing maximum allowed moisture, acidity, high-boiling residue, and other contaminants in new and reclaimed refrigerant, along with the test methods used to confirm purity.

A canister of desiccant placed in the flow path of recovery or recycling equipment to trap water and acid. It protects the recovery machine and improves the quality of the refrigerant being recycled.

A field check using an indicator tube or kit to see whether refrigerant or compressor oil has turned acidic from moisture-driven breakdown. A positive result usually means the charge should be reclaimed, not recycled.

A unit of absolute pressure equal to one thousandth of a millimeter of mercury. Atmospheric pressure is about 760,000 microns, so a properly evacuated system reads in the hundreds.

An electronic instrument that displays absolute vacuum in microns. It is connected directly to the system, not through long hoses, because oil and hose restrictions can make a gauge read far lower than the true vacuum.

A vacuum near 500 microns held long enough for moisture in the system to boil off. Reaching and holding it shows that both air and water vapor have been removed before charging.

A dehydration method that alternates pumping the system down to a deep vacuum with breaking the vacuum using dry nitrogen, done three times so moisture is carried out faster than with one long evacuation.

Air or nitrogen trapped in a system or cylinder that does not condense at normal condensing temperatures. It raises head pressure and shows up as a pressure that does not match the saturation temperature.

Flowing regulated dry nitrogen through an open line or component to push out air and moisture and prevent oxidation during brazing. The nitrogen is vented to the room, never sealed inside the system.

Adding refrigerant on a scale until the nameplate charge is reached. It is the most accurate charging method when the appliance has a known factory charge and no other method is needed.

The number of degrees a vapor is above its saturation temperature at the measured pressure. Superheat at the evaporator outlet shows whether the metering device is feeding the right amount of refrigerant.

The number of degrees a liquid is below its saturation temperature at the measured pressure. Subcooling at the condenser outlet shows how much liquid is stacked in the condenser and helps confirm charge on a TXV system.

The temperature at which a refrigerant boils or condenses at a given pressure. The pressure-temperature chart lets a technician convert between the two when charging or diagnosing a system.

Recovery cylinders may be filled only to 80 percent of their rated capacity by weight, leaving room for liquid to expand as the cylinder warms. Overfilling can rupture the cylinder hydraulically.

The portion of the Clean Air Act that bans knowingly venting ozone-depleting refrigerant and sets the rules for technician certification, recovery, recycling, reclaiming, and recordkeeping.

The rule that refrigerant must not be knowingly released to the atmosphere during service, maintenance, or disposal of an appliance. Small amounts released during good-faith recovery efforts are exempt.

A credential earned by passing an EPA-approved Type I, II, or III examination. Type II certification covers servicing high-pressure appliances other than small appliances, and certification is required to purchase refrigerant.

The written or electronic records that technicians and equipment owners must keep, covering refrigerant purchased, recovered, or disposed of, plus service history for appliances with large charges.

The risk that leaking refrigerant displaces oxygen in a closed space. Vapor is heavier than air and collects in low areas such as pits and basements, so the space must be ventilated and tested before entry.

Tissue damage from contact with liquid refrigerant, which boils at very low temperature and can freeze skin instantly. Gloves and eye protection are required whenever lines, valves, or cylinders are opened.

The schedule that ended U.S. production and import of HCFC-22 and other HCFCs on January 1, 2020. Existing equipment now runs on recovered or reclaimed refrigerant rather than newly made supply.

A comparative number showing how strongly a gas destroys stratospheric ozone, with CFC-11 set at 1.0. HCFC-22 is roughly 0.055, and HFCs are zero because they contain no chlorine.

A comparative number for the heat a gas traps over a set period, with carbon dioxide set at 1.0. Most HFCs have values in the hundreds to thousands, which drives today's phasedown rules.

An ASHRAE safety classification for mildly flammable refrigerants that have low toxicity. A2L systems require ignition-source control, proper ventilation, and charge limits, and are handled under EPA 608 rules.