HVAC CFC
Small appliances refrigerant recovery
1-) 80% recovery required: Technician uses equipment manufactured before November 15, 1993; compressor of the appliance is not operation 2-) 90% Recovery required: Technician uses equipment manufactured on and after November 15 1993; Compressor it the appliance is operations.
Shipping refrigerant containers
1-) Properly label the refrigerant container. 2-) Properly complete shipping paperwork. 3-) check that the refrigerant container meets DOT standards
Section 608 (CAA) regulations:
1-) Require service practices that maximize recycling of ozone depleting substances such as CFC and HCFCs. 2-) Set certification requirements for recycling and recovery equipment, technicians, and reclaimers. 3-)Restrict the sale of refrigerants only to certified technicians. 4-)Require persons or technicians servicing or disposing of air conditioning and refrigeration equipment to prove to the EPA that recycling and recovery equipment being used is in compliance with EPA rules. Require the immediate repair of substantial leaks in air conditioning and refrigeration equipment with a charge greater than 50 lb. 5-)Establish safe disposal requirements to ensure the removal of refrigerants from goods such as motor vehicle air conditioners, home refrigerators, and room air conditioners and prevent them from entering the waste stream with the refrigerant charge intact.
Purge Unit
A Purge unit is a device that removes air and water (non condensable) from the refrigerant in a centrifugal refrigeration system during normal operation and returns the recycled refrigerant to the system. All low pressure systems require a purge unit, because air and moisture can enter the system due to the atmosphere being at a higher pressure than the system. Low pressure chillers typically have moisture entering the system by air leaks that bring air and moisture through gasketed areas or fittings. Low pressure systems with open drive compressor are susceptible to leaks through the compressor shaft seal. the suction line of a purge unit is from the top of the condenser (non condensables accumulate in the condenser), and the discharge of the purge unit returns all condensables (refrigerant) to the system at the evaporator.
Low Pressure System Leak Testing
A hydrostatic tube test kit is a set of tools used to determine if tubes are leaking in the condenser of a chiller. Another method to check for refrigerant leak is to place a leak detector probe into the water box (with water removed) low pressure refrigeration system that are charged can be efficiently leak checked by raising system pressure with heat using controlled hot water or heating blankets. When leak testing empty systems, nitrogen is used; typically. 10 psi is the maximum nitrogen test pressure allowed during leak testing.
Leak Detector
A leak detector is a device that is used to detect refrigerant leaks in a pressurized air conditioning or refrigeration system. Leak detectors are available include electronic, fluorescent, ultrasonic fixed, or halide torch detectors. Soap bubbles are also used to pinpoint leaks in a system by converting the piping with a soapy solution. As the refrigerant leaks, bubbles are formed at the pint of the leak.
Pressure Temperature Chart (P-T Chart)
A pressure Temperature Chart is a reference tool used to determine the pressure of a refrigerant at a given temperature or to determine the temperature of a refrigerant at a given pressure. The boiling point or condensing point of a refrigerant is known as the saturation point. A P-T chart is a chart that shows corresponding saturation temperature for a giving pressure of a specified refrigerant. All Points on a P-T chart are saturation points.
Servicing Small Appliances
A sealed system of a small appliance with an operating compressor and a completely restricted capillary tube metering device requires only one access valve on the high pressure side of the system to evacuate the refrigerant.
Service Aperture
All small appliances must be equipped with a service aperture. A service aperture is a device used to add or remove refrigerant from a system. Small appliances typically have a service aperture, which consists of a straight piece of tubing that is entered by using a piercing access valve.
Venting Prohibition for refrigerant substitutes
An amendment was added in November 1995 to section 608 CAA that prohibits the venting of substitute refrigerants during the maintenance, service, repair and disposal of air conditioning and refrigeration equipment.
Type 1 (Small Appliances) classification
Are refrigeration products that are fully manufactured, charged, and hermetically sealed in a factory with 5 lb or less refrigerant.
Low-Loss Fittings
Are special fittings that prevent the release of refrigerant from a system to the atmosphere and prevent air from entering the system. Low loss fittings automatically trap refrigerant in a hose when disconnected and are required on all recovery, recycling and reclaiming equipment.
London Amendments to the Protocol (June 29, 1990)
At the second membership meeting of the Montreal Protocol parties, held in London on June 29, 1990, the parties to the Protocol passed amendments and adjustments which called for a full phase out of already regulated CFC refrigerants and Halons by the year 1996. The parties also voted to phase our HCFCs by the year 2020, but with the possibility of allowing use until the year 2040.
Absolute pressure
Atmospheric pressure + gauge pressure; PSIA= PSI+14.7
CFC And HCFC
CFC and HCFC gases are mixed throughout the atmosphere by large scale winds and survive the several year journey up to the stratosphere where CFCs are eventually broken down by ultraviolet radiation. The substances produced by breaking down the CFC molecules deplete the ozone layer. The decreased amount of ozone may let an increased amount of UV radiation penetrate the stratosphere and troposphere and reach the surface of the planet. Also, oxygen present in the stratosphere decreases the amount of UV radiation that the ozone layer is able to absorb.
CFC Recovery, Recycling and Reclaiming
CFC substance have not been manufactured since 1995. After 1995, supplies of CFC refrigerants for equipment servicing have come from recovery and recycling efforts. As time passes, CFC refrigerants will become harder to obtain. As CFC refrigerants become less available, CFC refrigerant will become too expensive to use.
Leak rate for appliances with more than 50lb
Commercial refrigeration 35% Industrial refrigeration 35% Comfort cooling 15% All others appliances 15%
ARI 740 Planned Small appliance Evacuations
Compressor status: operational; equipment manufacture before November 15 1993 80% refrigerant recovered or 4" hg vacuum; equipment manufacture after November 15 90% refrigerant recovered or 4" vacuum. Compressor status non operational; before November 15 80% and 4" vacuum; after November 15 80% 4" vacuum
Perfluorocarbons (PFCs)
Consisting of Carbon and fluorine. PFC refrigerant do not deplete stratospheric ozone. However, PFCs have extremely high global warming potentials (GWs) and very long lifetimes.
Dehydration and Evacuation
Dehydration is the process of removing moisture (water vapor) from air conditioning or refrigeration system. As air enters a system, moisture also enters. Moisture in an air conditioning or refrigeration system will cause acids to form. Dehydration of a system is accomplished by Evacuation the system. A system is dehydrated when a vacuum gauge shows that the desired deep vacuum has been reached and held. Factors that affect the evacuation time of a system include the following: 1-)Size of equipment being evacuated 2-)Ambient temperature 3-)Amount of moisture in the system 4-)Size (capacity) of the vacuum pump 5-) Length and diameter of hoses 6-) Whether the recovery vessel is packed in Ice
High Pressure system Dehydration
Dehydration is the removal of moisture from a high pressure appliance. Dehydration of a high pressure system is achieved by using a filter/dryer on an operating system, or using a vacuum pump to remove the moisture when not operating. Dry nitrogen is used to break the first vacuum after dehydrating a system by using the double evacuation method.
High pressure service tips
During service, the technician must understand the operation and function of all the valves on a high pressure system. Three way valves have three ports and two seat. To backseat a valve is to turn the valve in the counterclockwise direction to bring the valve stem to the front position. A suction service valve in the back seated position will have the gauge port closed. The valve must be cracked off of the backseat (all ports open) to open the gauge port.
The Prohibition on Venting
Effective July 1 1992, section 608 of the CAA prohibits individuals from knowingly venting CFC and HCFC ozone depleting substance into the atmosphere while maintaining, servicing, repairing, or disposing of air conditioning or refrigeration equipment (appliances). Only for types of releases are permitted under the prohibition: 1-) "De mínimis" (minimal) quantities of refrigerant released in the course of making good faith attempts to recover, recycle, or safely dispose of refrigerant. 2-) Refrigerant releases during the normal operation of air conditioning and refrigeration equipment, such as from mechanical purging and/or leaks. However, the EPA does require the repair of leaks above a specific size in large equipments. 3-) Release of CFCs or HCFCs that are not used as refrigerants. Any heat transfer fluids are considered refrigerants. For example, mixture of nitrogen and R-22 that are used as holding charges or as leak test gases may be released, because the ozone depleting compound is not used as refrigerant. 4-) Small releases of refrigerant that result from purging hoses or from connecting or disconnecting hoses to charge or service appliances d not be considered violations of the prohibition on venting. However, recovery and recycling equipment manufactured after November 15 1993 must be equipped with low loss fittings.
Equipment Grandfathering
Equipment manufactured before November 15 1993, including homemade equipment, may be grandfathered if the equipment meets the standards in the evacuation requirement tables.
ARI 740 Planned low pressure equipment evacuation
Equipment manufactures before November 15 1993: 25" Hg; Equipment Manufactured after November 15 29" Hg
High pressure system Evacuation
Evacuation is performed to remove Non condensables and particles that should not be mixed with the refrigerant of a high pressure system. Refrigerant recovery occurs before system evacuation. once repairs are completed on a high pressure system, the system is leak tested, then evacuated and charged with refrigerant. When a new high pressure system is assembled (built up), evacuation of the system to prescribed levels is the first service procedure performed.
Global Warming
Global warming is also known as the greenhouse effect. Global warming occurs when heat is trapped in the troposphere. The higher temperatures can have consequences such as drought, disease, floods and lost ecosystems.
Basic types of chillers
High pressure chillers, low pressure chillers and absorption chilled-water systems.
High pressure System Accessories
High pressure systems typically include filter/dryers, moisture indicators, thermal expansion valves, receivers, and accumulators.
Rupture Disk
In the event of excessive pressure, pressure is released from a centrifugal chiller safely with a rupture disc. A rupture disc is a one time use pressure safety device. Low pressure chillers typically use a rupture disc mounted on the evaporator housing to protect the system from over pressurization. A typical low pressure chiller rupture disc relieve pressure at 15 psi. The discharge from a rupture Distric must be pipped outdoors for venting refrigerant.
Gauge Manifold
Is a device that has two gauges, a manifold with valves, and connecting hoses to control refrigerant transfer. A gauge manifold is an important tool used when servicing air conditioning or systems. Gauges are used when charging a system with refrigerant or evacuating a system. The low-pressure (compound) gauge and connecting hose are typically blue in color. The low pressure gauge provides pressure readings above and below atmospheric pressure. The high pressure gauge and connecting hose are typically red in color. The high pressure gauge provides pressure readings from 0 PSI to 500 PSI. the center port on a three port gauge manifold is used during the recovery, evacuation and charging processes. A yellow hose is typically used with the center port.
Vacuum Pumps
Is a device used to create pressures below atmospheric pressure (vacuum in in. Hg) in a closed system. Vacuum pumps remove air, non condensable gases, and moisture from systems before charging the system. Evacuation is the process of removing air and moisture from air conditioning or refrigeration systems. Air can also contain moisture that damages equipment and causes the formation of hydrochloric acid in a system.
Chillers
Is a piece of refrigeration equipment that removes heat from water that circulates through a building for cooling purposes.
Passive Recovery (refrigerant)
Is a refrigerant recovery process achieved with the assistance of system components to remove the refrigerant from the system (pump-down). The passive recovery method can only be used with appliances designed to use 15lb or less refrigerant.
Active Recovery (refrigerant)
Is a refrigerant recovery process using a self contained recovery unit (machine). the active recovery method is the most popular method. The recovery unit removes the refrigerant with no assistance from system components.
Class II substances
Is a refrigerant that is considered to present a medium danger to the environment.
Class I substances
Is a refrigerant that poses the highest danger to the environment.
Ozone Layer
Is located in the stratosphere at approximately 28 miles above the earth's surface. The ozone layer plays the vital role of absorbing harmful ultraviolet (UV) radiation from the sun.
Pour Point
Is the lowest temperature a fluid can be at and still flow. Arctic cup is the test used to measure the pour point temperature of a liquid.
Fire Point
Is the temperature (higher than flash point) at which a fluid will burn for at least 5 seconds.
Flash Point
Is the temperature at which a fluid's vapor will ignite without the fluid igniting. Cleaveland cup is the test used to measure the flash point temperature of a fluid.
Refrigerant Recovery Machines
Long hoses between the air conditioning or refrigeration unit and the recovery machine must be avoided to avoid excessive pressure drops. Long hoses also cause an increase in the recovery time and an increase in refrigerant emissions if refrigerants escape to the atmosphere, because a longer hose has more volume.
Oil Foaming
Oil Foaming occurs in the crankcase of a compressor due to migration of refrigerant into the oil. Oil foaming can contribute to compressor failure (burnout). When a compressor burns out, an oil sample must be taken for analysis. (It is recommended to change the oil)
Advance Notice of Proposed Rulemaking (ANPRM)
On May 1, 1990, the EPA published an advance notice of proposed rulemaking (ANPRHL, 55 FR 18256) that address issues related to the development of a national CFC recycling program. The ANPRM notice emphasized the importance of recycling CFC refrigerants and allowed the continued use of equipment requiring CFC refrigerants.
The effects of ground level 1 ozone
Ozone are experienced in hot weather. According to the EPA, millions of people live in areas where ozone health standards are exceeded. Low-level ozone damages and vegetación and eco systems.
Ozone Destruction
Ozone is destroyed when ultraviolet radiation attacks a CFC molecule and break away chlorine atoms from the CFC molecule. The free chlorine atoms destroy ozone molecules, oxygen and chlorine monoxide molecules are formed in the stratosphere when chlorine atoms break down ozone molecules. The chlorine monoxide molecule is so unstable that the chlorine and oxygen atoms separate, allowing the chlorine atom to be free to attack other ozone molecules and continuing the cycle.
Section 608 (CAA)
Promotes minimizing emissions and maximizing recycling of ozone depleting substances. President George H. Bush announced on February 11 1992, that the U.S. would unilaterally accelerate the phase out schedule for ozone depleting substances, and called upon other nations to do so as well. President Bush also asked CFC, HCFC and Halon producing countries to voluntarily reduce production of ozone depleting substances.
Low pressure refrigerants
R-11 and R-123
High pressure refrigerants
R-12; R-22; R-114; R-500, R-502. Very high pressure: R-13 and R-503
Evidence of ozone depletion
Rain effectively scrubs the lower atmosphere clean, removing the natural forms of chlorine. Measurements show that concentration of natural chlorine vanish very rapidly as altitude increases. Neither sea salt from ocean evaporation or atmospheric-level volcanic eruptions contribute significantly to stratospheric chlorine levels. It is the stability of CFC molecules that allows the threat to the ozone layer to occur. Chlorine monoxide found in the upper stratosphere is another indication that the ozone layer is being destroyed. The strongest evidence that CFCs are in the stratosphere is a measurement of CFCs in air samples from the stratosphere. It is presently accepted that CFCs and other substances such as Halon used in human activities are the primary source of chlorine molecules in the stratosphere.
High pressure system R134a REfrigerant recovery
Recovering R-134a refrigerant requires special precautions. Recovery equipment recovering R-134a refrigerant must use special hoses, gauges, vacuum pumps, oil, and containers designed only for R-134a refrigerants.
Service Practice
Refrigerant Charge into a low pressure system must always be charged as refrigerant vapor first to avoid freeze ups, then as liquid refrigerant to speed up the process.
refrigerant Containers
Refrigerant containers are disposable or reusable. A disposable container is a container used only with new refrigerants. Disposable containers are designed for refrigerant extraction and are not used to receive refrigerants. Disposable containers such as DOT 39 are not to be reused under any circumstances. Disposable comes with the color designated to the refrigerant. A reusable container is a container designed to receive refrigerant and have refrigerant extracted, and are gray with yellow tops. Refrigerant storage cylinders can be filled to a maximum of 80% capacity.
Type j2 (High pressure equipment)
Refrigerant machines, packaged terminal air conditioning (PTAC) units, and split system air conditioning units (using R-22) re examples of high pressure equipment typically found in the type 2 category. Any equipment that contains over 5 lb of refrigerant and is not categorized as low pressure falls into the type 2 (high pressure equipment) category.
Reclaiming (refrigerant)
Refrigerant reclaiming is the reprocessing of used refrigerant to meet new refrigerant standards and includes chemical analysis to verify purity. Refrigerants that are seriously contaminated cannot be reclaimed. Refrigerants with serious contaminants, such as acid contaminants created from burnouts, are the most difficult for a reclaiming facility to handle successfully. When recovering refrigerant, it is important not to mix different refrigerants in the same container because most refrigerant mixtures are impossible to reclaim. Refrigerants that cannot be separated must be destroyed. Refrigerants should never be mixed.
Recovery
Refrigerant recovery is the removal of refrigerant in any condition from a system without testing or processing the refrigerant and storing the refrigerant in an external container. The recovery of refrigerants is necessary to ensure adequate supplies of refrigerants for present and future service use after production bans are in effect. Recovering refrigerants also prevents the venting of refrigerants to the atmosphere and ozone depletion. Recovery can be achieved by using passive or active methods.
Recycling (refrigerant)
Refrigerant recycling is the removal of refrigerant from a system and the cleaning of the refrigerant for reuse. Recycled refrigerant is refrigerant that has been processed using oil separators and single or multiple pass filter/dryers to separate moisture, acidity, and particulate matter from the refrigerant.
Chlorofluorocarbons (CFCs)
Refrigerants consisting of chlorine, fluorine and carbon. CFC are stable, nonflammable, low in toxicity and inexpensive to produce. Classified as Class I substances.
Hydrofluorocarbons (HFCS)
Refrigerants consisting of hydrogen and carbon. HFCS have no chlorine molecules and create no threat to the ozone layer. Present low danger or no danger to the environment.
Hydrochlorofluorocarbons (HCFCs)
Refrigerants consisting of hydrogen, chlorine, fluorine and carbon. HCFC are less harmful to the environment. Classified as Class 2 substances.
Recovery machines (Type 1)
Refrigerants used in current small appliances such as campers or recreational vehicles must not be recovered without refrigerant specific approved recovery machines and devices. the refrigerants found in campers and recreational vehicles are ammonia, hydrogen, and water. New recovery devices are not compatible with camper and recreational vehicle refrigerant.Specific recovery machines must be used that are designed to work with ammonia or with hydrogen.
Ionoshere
Region above the stratosphere; approximately 31 to 300 miles above the surface of the earth.
Stratosphere
Region above the troposphere; is approximately 8 to 30 miles above the surface of the earth
Regulatory Requirements
Replacement of any major component of a low pressure appliance such as an evaporator coil is considered to be a "major" repair under EPA regulations. Under EPA regulations, controlled hot water can be used to pressurize a low pressure system for non major repairs. replacement of any major component of a low pressure appliance such as an evaporator coil is considered to be a "major" repair , and replacement of a component such as a temperature sensor is considered to be a "minor" repair under EPA regulation.
Recordkeeping
Section 608 of the CAA requires that any person who sell CFC and HCFC refrigerant retain invoices that indicate the name of the purchaser, the date of the sale and the quantity of the refrigerant purchased. The records kept by sellers must be maintained for a minimum of three years. Wholesalers who sell refrigerants to companies that employ certified technicians must keep proof of buyer certifications (copies of certification cards) and a list of authorized personnel or job titles/classifications who may purchase refrigerants to be used by the certified technician employed at the same company.
ARI 740 Planned High pressure Equipment Evacuation
See Picture page 30 (pay version to add picture)
Service Practices
Service practice for high pressure equipment include refrigerant recovery, evacuation, charging, and system leak testing. When performing service to a high pressure system, the technician must remember the importance of protecting the environment, equipment and most of all, people.
EPA Evacuation Requirements
Since July 13 1993, Technicians have been required to evacuate air conditioning and refrigeration equipment to established vacuum levels when opening equipment. Recovery and Recycling equipment must be certified by an EPA approved equipment testing organization. Preston's who add refrigerant to an appliance to top off the system are not required to evacuate the system.
Recovery Regulations
Small appliances are allowed to have refrigerant recovered using the passive method of recovery. The passive method of refrigerant recovery can only be used when less than 15 lb of refrigerant will be recovered from the high pressure side. Because small appliance can use the passive method of refrigerant recovery, self contained recovery machines are not always required.
Small Appliance components
Small appliances have refrigeration systems made up of the same components as other refrigeration systems. Small appliances systems have compressors, condensers, metering devices and evaporators.
Pressure Readings from Recovery Cylinders
Technicians can obtain pressure readings from recovery cylinders. Accurate pressure readings of the refrigerant inside a recovery cylinder are important for the following reasons: 1-)Pressure readings can indicate if excessive air or other non condensables are present in the cylinder. 2-) Pressure readings can indicate if the refrigerant has been broken down (made unusable) Accurate pressure readings are only possible if the refrigerant in the recovery cylinder is allowed to stabilize to ambient temperature before any comparisons to a pressure temperature chart are made.
High pressure system refrigerant recovery precautions
Technicians must never mix refrigerants in any manner when recovering refrigerant into storage containers. Any kind of contamination must be avoided at all cost. When recovering high pressure refrigerants, the following precautions must be observed to protect equipment from damage: 1-) Never recover refrigerant with a recovery machine while the system compressor is operating. A hermetically sealed compressor has the potential to overheat when deep vacuums (500 microns) are being created because the electric motor relies on the flow of refrigerant through the compressor for cooling. As the vacuum is deepened, there is less refrigerant remaining in the system to cool the compressor motor. 2-) Recovery and recycling machines that contain R-502 refrigerant and that must be used to recover refrigerant from a system with R-22 refrigerant require the technician to recover as much of the R-502 refrigerant from the recovery machine as possible, then change filters and evacuate the recovery machine. 3-) Recovered refrigerant may contain acids, moisture and lubricating oils. If recovered refrigerant is not damaged or contaminated, the refrigerant can be charged back into the same system or another system under the same ownership once system repairs are completed. 4-) System dependent (passive) refrigerant recovery cannot be used when a high pressure appliance contains over 15 lb of high pressure refrigerant .
Regulatory requirements (Type 1)
Technicians servicing small appliances must be certified in refrigerant recovery if the technician is to perform work on a sealed system after November 145 1994. If any EPA regulations change after a technician becomes certified, it is responsibility of the technician to comply with any changes to the law.
Clean Air Act Amendments (CAA)
The Clean Air Act Amendments (CAA) of 1990, signed November 15 1990, included requirements for controlling ozone-depleting substances.
Technician Certification
The EPA has established a technician certification program for technicians who perform maintenance, service, or repair, or who dispose of equipment that could be reasonably expected to release refrigerants into the atmosphere. Section 608 of the CAA allows work that would not be expected to release refrigerant into the atmosphere to be performed on equipment by non certified personnel. Apprentices are except of certification requirement as long as supervised by a certified technician.
Exceptions to Evacuation Requirements
The EPA has established limited exceptions to the evacuation requirement for repairs to leaky equipment such as repairs that are not considered major and when evacuation of the equipment to the environment is not required.
Regulatory requirements (Type 2)
The EPA requires that all appliances containing more than 50 lb of refrigerant (except for commercial and industrial process refrigeration) be repaired when the leak rate of the appliance exceeds 15% of the charge per year. Leaking commercial and industrial process refrigeration must be repaired when the leak rate exceeds 35% of the charge per year.
Equipment Certification
The EPA requires that recovery and recycling equipment manufactured on or after November 15 1993, be tested by an EPA approved testing organization. Recovery and recycling equipment intended for use with air conditioning and refrigeration equipment must be tested under the ARI 740-1993 test Protocol. The recovery and recycling equipment intended for use with air conditioning and refrigeration systems must be able to recover a specific percentage of refrigerant or create a specific level of vacuum on the system.
Montreal Protocol (September 16 1987)
The United States and 22 other countries signed the Montreal Protocol on substances that deplete the ozone layer. The Montreal Protocol is an international environmental agreement that establishes requirements to phase out ozone-depleting CFC substances worldwide.
Low Pressure equipment
The largest systems in the air conditioning and refrigeration industry are made up of low pressure equipment.
Troposphere
The region that covers the surface of the earth to about 6 to 7 miles up.
Boiling Point
The temperature at which a liquid changes to a gas
Condensing point
The temperature at which a substance changes from a gas to a liquid.
Low pressure refrigerants
The two most common refrigerants used in low pressure equipment are R-11 and R-123. Both have relatively high boiling points compared to most refrigerants, which result in low system operating pressure. Because low pressure equipment is very large (with large amounts of water), precautions must be taken to prevent any type of freeze up in the system. When CFC-11 refrigerant is at a pressure of 18.1" Hg vacuum, the saturation temperature will be about 32F and the water in the heat exchanger would being to freeze. The pressure corresponding to 32F for HCFC 123 is about 20" Hg vacuum. Technicians must be cautious not to allow chillers with R=11 and R-123 refrigerants to reach vacuum levels that would cause water to begin freezing.
Low pressure refrigerant recover y and charging procedures
The typical setting for the high pressure cutout control on a recovery unit used for evacuating the refrigerant from a low pressure chiller is 10 psi. After reaching the required recovery vacuum on a low pressure appliance, a technician must wait a few minutes to see if the system pressure rises, indicating that there is still refrigerant in liquid form or refrigerant still in the oil.
High pressure system Refrigerant Charging
The vapor method of charging is used when charging a system with a small amount of refrigerant. If a high pressure system is to be charged with a large amount of refrigerant, the refrigerant is charged as a liquid.
Increasing Speed of refrigerant recovery in a high pressure system
There are certain techniques and procedures that will decrease recovery time for refrigerant from a high pressure system. Technicians want to recovery to be as quick as possible. When there is flow of any kind, the flow rate is always the greatest where the pressure or temperature difference is the greatest. 1-) Removing the refrigerant change from a system is accomplished more quickly by packing the recovery container (cylinder) in ice. 2-) Before transferring refrigerant to an empty cylinder, the empty cylinder must be evacuated. 3-) TEchnicians can save time recovering refrigerant from a system by removing as much of the refrigerant as possible in the liquid state. After the liquid refrigerant has been recovered from a high pressure appliance, any refrigerant vapor is condensed by the recovery machine and recovered.
piercing Access Valves
To gain access into the sealed system of a small appliance, a piercing access valve is used. Piercing access valves are installed on service apertures or suction's lines of a system. When installing a piercing access valve onto a sealed system, the valve must be leak tested before proceeding with refrigerant recovery. If a soldier less type access valve is used, the soldier less valve must not remain installed on the system after completion of repairs. Solder less type access valves leak over time due to vibrations and therefore are considered temporary access valves.
High pressure system components
Typically include reciprocating, screw, or scroll compressors. High pressure appliance compressors have hermetically sealed, seme hermetic or open housings. Condensers used in high pressure systems can be air cooled or water cooled. Air cooled condensers are of a tube and fin design, while water cooled condensers are of a coil in shell or tube in shell design. The metering device typically used on high pressure appliances is a thermostatic expansion valve. The evaporator can be dry expansion or flooded. The evaporator will be of fin and tube, coil in shell or tube in shell design.
Ultraviolet Radiation
Ultraviolet radiation is the portion of the light spectrum that is damaging to living organisms. the greater the ozone depletion, the greater the amount of UV radiation reaching the surface of the planet. The harmful effects of UV increases as a result of ozone depletion. Ultraviolet radiation has been linked to skin cancer, cataracts, damage to materials like plastics, and harm to crops and marine organisms.
Refrigerant Sales Restrictions
Under EPA regulations, only certified technicians are allowed to purchase CFC or HCFC refrigerants. Technicians who have completed an EPA-approved certification program under either section 608 or section 609 are issued a certification card and are eligible to purchase refrigerants containing CFCs or HCFCs.
Recovery Requirements for small appliance disposal (Type 1)
Under Section 608 of the CAA, recovery equipment used to recover CFC, HCFC and HFC refrigerant from small appliances prior to final disposal must meet the same performance standards as recovery equipment used for servicing small appliances. the recovery machine used for recovering refrigerant from small appliances destined for disposal does not have to be tested by a laboratory. To ensure that technicians are recovering the correct percentage of refrigerant by either recovery method, technicians must use recovery equipment according to industry standards.
Safe Disposal Requirements
Under the rules of the EPA, equipment that is typically dismantled onsite before disposal, such as retail food freezers, residential central air conditioners, chillers, and industrial process refrigeration systems, must have the refrigerant recovered for disposal in accordance with the requirements of the EPA. However, equipment that typically enters the waste stream with the charge intact, such as motor vehicle air conditioners and household refrigerators, freezers, and room air conditioners, are subject to special safe disposal requirements. Under thee safe disposal requirements, the final person in the disposal chain (scrap metal recycler or landfill owner) is responsible for ensuring that refrigerant is recovered from equipment before the final disposal of the equipment occurs.
Low pressure System Evacuation
Water must be circulated through a low pressure chiller during system evacuation in order to prevent the freezing of water. Technicians must be aware that when evacuating a system to prescribed levels, the use of a large vacuum pump could cause trapped water to freeze. During evacuation of a low pressure system with large amounts of moisture, the system may require that pressure be increased with a gas such a nitrogen to counteract any freezing.
Recovery Practices
When a system compressor is inoperative, piercing access valves must be installed on both the high pressure and low pressure side of the system to recover refrigerant using the active method efficiently.
High pressure system leak testing
When inspecting a hermetically sealed compressor system that is known to have a leak, technicians should look for traces of refrigerant oil. Testing with soap bubbles is a typical method used for pinpointing refrigerant leaks in high pressure systems. Checking for proper superheat is another way to find a leak. A low refrigerant charge resulting from leak in the system starves the evaporator of refrigerant, increasing the superheat. Excessive superheat can be used as an indicator of a leak in a high pressure system.
High pressure system refrigerant recovery techniques
When recovering high pressure refrigerant, technicians must remember to always recover the refrigerant from the lowest point fo the system to have gravity aid in the recovery. King Valve.
removing oil
When removing oil from a low pressure system, the compressor oil should be heated to 130F, because less refrigerant is contained in the oil at the higher temperature.
Schrader Valve
When using recovery cylinders and equipment with Schrader valves, it is critical to: 1-) Inspect Schrader valve cores for bends and breakage 2-)Replace damaged Schrader valve cores to prevent leakage 3-) Cap the Schrader Valve Ports to prevent accidental damage to the valve core and refrigerant leaking.
low pressure refrigerant recovery and recycling
With a low pressure chiller, technicians must recover the liquid refrigerant first, and then recover the refrigerant vapor. During refrigerant vapor removal from the low pressure system, the system water pumps, recovery compressor and recovery condenser water supply must all be on.
Viscosity
a liquid's resistance to flow. Is the measurement of a fluid's internal resistance to flow.
Copenhagen Revisions to the Montreal Protocol (November 25, 1992)
on November 25 1992, the fourth meeting of the Montreal Protocol parties was convened in Copenhagen. The attending parties took a number of actions, including acceleration of the phase out of CFC refrigerants and Halons. HCFC refrigerants were also added to the list of chemicals tho be controlled under the Montreal Protocol. The new schedule stopped to production of Halons after 1993 and CFCs after 1995. HCFC refrigerants can be produced until 2030. Talks may accelerate the schedule to the year 2020. The Montreal Protocol is a global policy and the Clean Air Act (CAA) is a federal law of the United States.
Accumulation (Level Ozone)
there are human environmental effects of ozone depletion. Ozone depletion contributes to or can cause skin cancer (which is now one of the fastest growing forms of cancer), cataracts, and damage to the human immune system. Ozone depletion affects marine and plant life by reducing growth. At present, ozone depletion is limited to certain regions, but is considered a global problem.
Low Pressure Refrigerant Charging
when charging a low pressure chiller, freeze up must be avoided. Refrigerant is typically added to a centrifugal chiller (machine) through the evaporator charging valve. When charging refrigerant, a technician must charge refrigerant vapor first to avoid any freeze up, because liquid refrigerant charged into a low pressure system under a deep vacuum will build and lower temperatures enough to freeze water in the evaporator tubes. Technicians know when enough refrigerant vapor has been charged into a low pressure refrigerant system by the refrigerant saturation temperature increasing to 36F. Once refrigerant vapor is charged, liquid refrigerant can then be charged into a low pressure system.
