CORE

Ozone Depletion

• Destruction of ozone by chlorine
• Presence of chlorine in CFC and HCFC refrigerants
• Identification of CFC, HCFC, and HFC refrigerants (not chemical formulas, but idea that R-12 is a CFC, R-22 is an HCFC, R-134 is an HFC, etc.)
• Idea that CFCs have higher ozone-depletion potential (ODP) than HCFCs, which in turn have higher ODP than HFCs
• Health and environmental effects of ozone depletion
• Evidence of ozone depletion and role of CFCs and HCFCs

Clean Air Act and Montreal Protocol

• CFC phaseout date
• Venting prohibition at servicing
• Venting prohibition at disposal
• Venting prohibition on substitute refrigerants in November, 1995
• Maximum penalty under CAA
• Montreal Protocol (international agreement to phase out production of ozone-depleting substances)

Section 608 Regulations

• Definition/identification of high and low-pressure refrigerants
• Definition of system-dependent vs. self-contained recovery/recycling equipment
• Identification of equipment covered by the rule (all air-conditioning and refrigeration equipment containing CFCs or HCFCs except motor vehicle air conditioners)
• Need for third-party certification of recycling and recovery equipment manufactured after November 15, 1993
• Standard for reclaimed refrigerant (ARI 700)

Substitute Refrigerants and oils

• Absence of "drop-in" replacements
• Incompatibility of substitute refrigerants with many lubricants used with CFC and HCFC refrigerants and incompatibility of CFC and HCFC refrigerants with many new lubricants (includes identification of lubricants for given refrigerants, such as esters with 134; alkylbenzenes for HCFCs)
• Fractionation problem--tendency of different components of blends to leak at different rates

Refrigeration

• Refrigerant states (vapor vs. liquid) and pressures at different points of refrigeration cycle; how/when cooling occurs
• Refrigeration gauges (color codes, ranges of different types, proper use)

Three R's

• Definitions
• • Recover
  • Recycle
  • Reclaim

Recovery Techniques

• Need to avoid mixing refrigerants
• Factors affecting speed of recovery (ambient temperature, size of recycling or recovery equipment, hose length and diameter, etc.)

Dehydration Evacuation

• Need to evacuate system to eliminate air and moisture at the end of service

Safety

• Risks of exposure to refrigerant (e.g., oxygen deprivation, cardiac effects, frost bite, long-term hazards)
• Personal protective equipment (gloves, goggles, self-contained breathing apparatus--SCBA--in extreme cases, etc)
• Reusable (or "recovery") cylinders vs. disposable cylinders (ensure former DOT approved, know former's yellow and gray color code, never refill latter)
• Risks of filling cylinders more than 80 percent full
• Use of nitrogen rather than oxygen or compressed air for leak detection
• Use of pressure regulator and relief valve with nitrogen

Shipping

• Labels required for refrigerant cylinders (refrigerant identification, DOT classification tag)

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TYPE 1 (Small Appliances)

Recovery Requirements

• Definition of "small appliance"
• Evacuation requirements for small appliances with and without working compressors using recovery equipment manufactured before November 15, 1993
• Evacuation requirements for small appliances with and without working compressors using recovery equipment manufactured after November 15, 1993

Recovery Techniques

• Use of pressure and temperature to identify refrigerants and detect noncondensables
• Methods to recover refrigerant from small appliances with inoperative compressors using a system-dependent or "passive") recovery device (e.g., heat and sharply strike the compressor, use a vacuum pump with non-pressurized recovery container)
• Need to install both high and low side access valves when recovering refrigerant from small appliances with inoperative compressors
• Need to operate operative compressors when recovering refrigerant with a system-dependent ("passive") recovery device
• Should remove solderless access fittings at conclusion of service
• 134a as likely substitute for 12

Safety

• Decomposition products of refrigerants at high temperatures (HCl, HFl etc)

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TYPE 2 (High-Pressure)

Leak Detection

• Signs of leakage in high-pressure systems (excessive superheat, traces of oil for hermetics)
• Need to leak test before charging or recharging equipment
• Order of preference for leak test gases (nitrogen alone best, but nitrogen with trace quantity of 22 better than pure refrigerant)

Leak repair requirements

• Allowable annual leak rate for commercial and industrial process refrigeration
• Allowable annual leak rate for other appliances containing more than 50 lbs of refrigerant

Recovery Techniques

• Recovering liquid at beginning of recovery process speeds up process
• Other methods for speeding recovery (chilling recovery vessel, heating appliance or vessel from which refrigerant is being recovered)
• Methods for reducing cross-contamination and emissions when recovery or recycling machine is used with a new refrigerant
• Need to wait a few minutes after reaching required recovery vacuum to see if system pressure rises (indicating that there is still liquid refrigerant in the system or in the oil)

Recovery Requirements

• Evacuation requirements for high-pressure appliances in each of the following situations:
• • Disposal
  • Major vs. non-major repairs
  • Leaky vs. non-leaky appliances
  • Appliance (or component) containing less vs. more than 200 lbs
  • Recovery/recycling equipment built before vs. after November 15, 1993
• Definition of "major" repairs
• Prohibition on using system-dependent recovery equipment on systems containing more than 15 pounds of refrigerant

Refrigeration

• How to identify refrigerant in appliances
• Pressure-temperature relationships of common high-pressure refrigerants (may use standard temperature-pressure chart--be aware of need to add 14.7 to translate psig to psia)
• Components of high-pressure appliances (receiver, evaporator, accumulator, etc.) and state of refrigerant (vapor vs. liquid) in them

Safety

• Shouldn't energize hermetic compressors under vacuum.
• Equipment room requirements under ASHRAE Standard 15 (oxygen deprivation sensor with all refrigerants)

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TYPE 3 (Low-pressure)

Leak Detection

• Order of preference of leak test pressurization methods for low-pressure systems (first: hot water method or built-in system heating/pressurization device such Prevac; second: nitrogen)
• Signs of leakage into a low-pressure system (e.g., excessive purging)
• Maximum leak test pressure for low-pressure centrifugal chillers

Leak repair requirements

• Allowable annual leak rate for commercial and industrial process refrigeration
• Allowable annual leak rate for other appliances containing more than 50 lbs of refrigerant

Recovery Techniques

• Recovering liquid at beginning of recovery process speeds up process
• Need to recover vapor in addition to liquid
• Need to heat oil to 130F before removing it to minimize refrigerant release
• Need to circulate or remove water from chiller during refrigerant evacuation to prevent freezing
• High-pressure cut-out level of recovery devices used with low-pressure appliances

Recharging Techniques

• Need to introduce vapor before liquid to prevent freezing of water in the tubes
• Need to charge centrifugals through evaporator charging valve

Recovery Requirements

• Evacuation requirements for low-pressure appliances in each of the following situations:
• • Disposal
  • Major vs. non-major repairs
  • Leaky vs. non-leaky appliances
  • Appliance (or component) containing less vs. more than 200 lbs
  • Recovery/recycling equipment built before vs. after November 15, 1993
• Definitions of "major" and "non-major" repairs
• Allowable methods for pressurizing a low-pressure system for a non-major repair (controlled hot water and system heating/pressurization device such as Prevac)
• Need to wait a few minutes after reaching required recovery vacuum to see if system pressure rises (indicating that there is still liquid refrigerant in the system or in the oil)

Refrigeration

• Purpose of purge unit in low-pressure systems
• Pressure-temperature relationships of low-pressure refrigerants

Safety

• Equipment room requirements under ASHRAE Standard 15 (oxygen deprivation sensor with all refrigerants)
• Under ASHRAE Standard 15, need to have equipment room refrigerant sensor for 123