Refrigerant Charging and Service Procedures 9781733817202

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CRAIG MIGLIACCIO

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Refrigerant Charging and Service Procedures for Air Conditioning Preamble The author, Craig Migliaccio, is a licensed Career and Technical Education Teacher of HVACR (Heating, Ventilating, Air Conditioning, and Refrigeration), Sheet Metal, and Building Maintenance, in the State of New Jersey in the United States of America. Craig is also the owner of an HVACR contracting business with over 16 years of experience in the field. Communication with technicians across the United States, Canada, and other countries led Craig to develop this book as a resource for those who want to grow in the understanding of air conditioning and refrigeration systems. The goal is to provide a comprehensive guide that includes the understanding of refrigerants and the refrigeration cycle all the way through to the charging and troubleshooting of these refrigerant based systems. Videos of procedures may also be found at www.youtube.com/acservicetechchannel and at www.acservicetech.com. Illustrators: Olivia VanDeventer (Images, Layout and Design, Cover) Micah Wenker (Images) Brandon Price (Layout and Design) Proofreader: Frank Ackley References: EPA, Environmental Protection Agency, 27 Feb. 2019, www.epa.gov/. "Stationary Refrigeration and Air Conditioning." EPA, Environmental Protection Agency, 1 Nov. 2018, www.epa.gov/section608.

© 2019 Craig Migliaccio. All Rights Reserved. Second Printing. No part of this book may be reproduced and/or distributed in any form without the prior written consent of the author, Craig Migliaccio. For business and other inquires, contact [email protected]. ISBN# 978-1-7338172-0-2

Disclaimer The author, Craig Migliaccio,AC Service Tech LLC, and any other entitles involved with the creation of this book, under no circumstances, shall be held responsible for any damage or physical harm to persons or property or losses of any nature that may occur as a result of any interpretation and/or application of information, procedures, testing, or descriptions stated in this book. Although the author, Craig Migliaccio, and AC Service Tech LLC have made every effort to ensure that information in this book is correct and current at the date of publication, the author, Craig Migliaccio, and AC Service Tech LLC do not assume and hereby disclaim any liability to any party for any loss, damage, or disruption caused by errors and/or omissions, whether such errors and/or omissions result from negligence, accident, or any other cause. This book is not a substitute for a formal HVACR education and/ or apprenticeship under a licensed professional but is a complement to such training. This book exists to help retain procedures, give a deeper understanding of how air conditioning and refrigeration systems work, and to connect real life applications to what is taught in the classroom. Any and all manufacturer installation and service literature and code books, along with their recommended practices, shall supersede any recommendations or procedures mentioned in this book. Always wear safety glasses, butyl lined gloves, and other PPE (Personal Protective Equipment) prior to accessing a system's refrigerant ( charge. Always make sure to have fresh air available or wear a SCBA (Self- ( Contained Breathing Apparatus) and never breathe in refrigerant gases. For ( more information on safety, refer to the refrigerant specific SDS (Safety Data Sheet, formally known as Material Safety Data Sheet) for each refrigerant prior to handling. Make sure to follow all other safety rules stated through https://www.epa.gov and https://www.epa.gov/sectlon608 as well as through an approved EPA 608 certification testing agency. In the United States of America, technicians must have the appropriate EPA 608 Type 1, Type 2, Type 3, or Universal Certification prior to working on any refrigerant based system or buying refrigerant. Be sure to follow all local laws, codes, and requirements.

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Table of Contents Chapter 1. Understanding Refrigerants and the Refrigeration Cycle......................... 1 1. The Refrigeration Cycle................................................................................. 1 2. Refrigerants Used in the Refrigeration Cycle. ............................................... 2 3. Explanation of Section 608 Certification........................................................ 4 4. The Saturated State of a Refrigerant............................................................. 6

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Chapter 2. The Refrigeration Cycle, Components, Definitions, and Locations..... .... 1. Basic Refrigeration Cycle.............................................................................. 2. The Refrigeration Cycfe and Component Definitions ..................................... 3. Four Basic Components Shown on an Air Conditioning System................... 4. Changing of Refrigerant States...................................................................... 5. Two Components Separating the High Side and the Low Side ..................... 6. Explaining the Separation of the High and Low Side of the System............. 7. Components Included in the Low Pressure Side of the System ....................

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Chapter 3. The Steps of the Refrigeration Cycre........................................................ 1. The Complete Refrigeration Cycle of a Split System Air Conditioner..... ....... Step 1. Compressor Infet.......................................................................... Step 2. Compressor Outlet....................................................................... Step 3. Condenser Vapor De-Superheating ............................. ... .. .. . .. ... .. Step 4. Condenser Saturated State.......................................................... Step 5. Condenser Liquid Subcooling ...................................................... Step 6. Subcooling ................................................................................... Step 7. Liquid Enters the Filter Drier........................................................ Step 8. Liquid Enters the TXV Metering Device.. ..................................... Step 9. Liquid Exits the TXV Metering Device .......................................... Step 10. Evaporator Saturated State Begins.. ......................................... Step 11. Evaporator Saturated State....................................................... Step 12. Evaporator Vapor Superheating........ ............. ...... ... ..... ... .... ...... Step 13. Superheat.................................................................................. Step 14. Total Superheat........................... ..................................... .......... Step 15. Compressor Inlet Again ..............................................................

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2. Heat Pump Refrigeration Cycle in Cooling Mode (Steps 1-22). .. ... .. .. .... ... .. .. 3. Heat Pump Refrigeration Cycle in Heating Mode (Steps 1-22)........... .... ..... 4. Evaporator and Condenser Heat Exchangers....... ....................................... A. Evaporator Coil Explanation in Cooling Mode....................... ....... ....... B. Condenser Coil Explanation in Cooling Mode............................... ......

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Chapter 4. Refrigerant Pressure and Temperature..................................................... 1. Measuring the Pressureffemperature of the Refrigerant Bottle and of the System.. 2. How to Read the Pff Chart............................................................................. 3. How to Determine What Refrigerant is in a Used Recovery Bottle................ 4. How to Determine What Refrigerant is in a System....................................... 5. Alternative R-22 Refrigerants and Distinguishing Between Refrigerants ....... 6. Measuring the Saturated States of a Running Air Conditioning System........ 7. Refrigerant Gauges Have Built-In PIT Charts................................................ 8. Compound Manifold Gauge Set and Hose Connections............................... 9. Digital Manifold Sets, Sensors, and Wireless Instruments............................. 10. Digital Temperature Readers..........................................................................

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Chapter 5. Service Access Ports.......................... , ............................................................ * ...................... 1. Safety............................................................................................................. 2. Access the System Refrigerant Charge.......................................................... 3. Sweat/Braze-On Access Port......................................................................... 4. Clamp-On Piercing Access Port..................................................................... 5. Bolt-On Piercing Access Port......................................................................... 6. Squeeze Type Piercing Access Tools............................................................. 7. Port Caps....................................................................................................... 8. Port Connection for Service............................................................................

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Chapter 6. Serv-ice Valves........................................................................................... 1. The Three Position Service Valve for Refrigeration ........................................ 2. The Three Position Service Valve for Air Conditioners and Heat Pumps..... .. A. The Three Positions for Air Conditioners and Heat Pumps................. . B. The Front-Seat Position........................................................................ 3. Connection to and Disconnection from a Three Position Service Valve Port. A. Steps for Connection of the Refrigerant Hose to the Service Port....... 8. Steps for Disconnection of the Refrigerant Hose from the Service Port. 4. The Two Position Service Valve..................................................................... 5. Other Service Valves and Ports..................................................................... 6. The Connection and Disconnection of the Manifold Gauge Set Hoses to and from the System Service Ports (Steps 1-9).......................................... ..

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Chapter 7. Checking the Refrigerant Charge............................................................. 66 a 1. Methods to Check the Refrigerant Charge..................................................... 66 0 2. Subcooling Method........................................................................................ 67

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A. Target Subcooling ............................................................................................................, ............... B. Subcooling Method Example................................................................ C. TXV Effectiveness and Delta T... ................. ...... .... .. .... ............. ... ...... .. 3. Total Superheat Method.................................................................................. A. Total Superheat Example...................................................................... B. Target Superheat.................................... * •••• ,.......................................................................... C. Total Superheat Method, Step by Step................................................ D. Example Using the Total Superheat Method........................................ E. Undercharged and Overcharged Scenarios......................................... F. Measuring Delta Twhen Using the Total Superheat Method................ 4. Determining the Refrigerant Charging Method............................................... 5. Quick Guide for Checking the Refrigerant Charge......................................... A. Subcooling.... ........................................................................................ B. Total Superheat............... ,................................................................................................. 6. Refrigerant Charging Procedures for Packaged Units................................... 7. The Total Weight Method................................................................................

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Chapter 8. Charging and Recovery of Refrigerant..................................................... 85 1. Hose Setup and Air Purging........................................................................... 85 2. Charging Refrigerant into the System............................................................ 88 3. Recovering Refrigerant into a Pressurized Recovery Bottle.......................... 97 4. The Disconnect Procedure............................................................................ 100 5. How to Avoid the Disconnect Procedure When Measuring Pressure............ 102 6. Leak Detection at the Access Ports ................................................................ 103 ... ,.__

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Chapter 9. Refrigerant Recovery Machine Setup and Bottle Preparation .................. 104 1. Recovery Bottle.............................................................................................. 104 2. Preparation of a Recovery Bottle................................................................... 104 3. Recovery Machine Setup and Procedure...................................................... 109 4. Recovery Procedure After the Hose Setup is Connected .............................. 112

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Chapter 10. System Preparation Prior to Adding Refrigerant.. ................................... 116 1. System Preparation Steps................................................ 116 A. Install the Refrigerant Tubing ................................................................ 116 B. Flow Nitrogen While Brazing ................................................................ 117 2. Pressure Testing ............................................................................................. 118 3. Leak Detection................................................................................................ 119 4. The Oil Blow Out Procedure........................................................................... 121 5. Introduction to the Vacuum Procedure........................................................... 122 A. The Vacuum Procedure....................................................................... 122 If • • • • • • • • • • • ' " ' • • • • • • • • • • • • • • • •

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B. Vacuum Strategies.................................................................................."......... 125 C. Vacuum Setups ..................................................................................... 126 D. Vacuum Tools ........................................................................................ 128 E. Starting The Vacuum Procedure........................................................... 128 6 . The Standing Vacuum Test. ........................................................................... 130 7. Breaking the Vacuum with Refrigerant.. ......................................................... 131 A. The Vacuum Procedure, Standing Vacuum Test, and Breaking the Vacuum with Refrigerant from the System, Step by Step..................... 131 B. Breaking the Vacuum with Refrigerant from the Outdoor Unit Using the Ratcheting Service Wrench ............................................................. 135 C. Breaking the Vacuum with Refrigerant from the Bottle........................ 135 8. The Problem of a Rising Micron Level During the Standing Vacuum Test..... 138 9 . Triple Evacuation..................................................................................................... 139 10. Vacuum Tool Maintenance............................................................................. 140 A. Vacuum Pump...................................................................................... 140 8. Vacuum Gauge..................................................................................... 141 C. Vacuum Hoses and the Valve Core Removal Tool.. ............................. 141

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Chapter 11. The Pump Down Procedure .................................................................... 142 1. Pump Down Explained................................................................................... 142 2. Steps for a Pump Down on a Split System with Two Position Service Valves.. 143 3. Troubleshooting Using the Pump Down Procedure ....................................... 145 0 Chapter 12. Other Charging Methods......................................................................... 147 1. Connecting the Manifold Gauge Set to a Heat Pump in Heating Mode......... 147 2. Checking the Refrigerant Charge When the Outdoor Ambient Temperature is Below 70° F ................................................................................................ 148 3. Measuring the Low Side Saturated Temperature, Superheat, and Subcooling Without Reading Pressure........................................................... 149 4. Inefficient and/or Inaccurate Methods to Check a Refrigerant Charge.......... 151 A. Introduction to the Methods.................................................................. 151 8. Ambient +30 Rule................................................................................. 152 C. Ambient +25 Rule................................................................................. 152 D. Vapor Line Sweating .............................................................. ... "······ .......................... 152 E. Feeling How Cold the Vapor Line is with the Hand .............................. 153 F. Setting the Pressure for the Low Side or High Side Depending on the Outdoor Ambient Temperature and Personal Experience.................... 153 G. Delta T ................................................................................................. 155 H. Targeting a 40° F Saturated Temperature Target on the Low Side ...... 156

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Chapter 13. Troubleshooting an Air Conditioning System ......................................... 158 1. Basic Procedure Performed Prior to Checking the Refrigerant Charge on a Service Call ................................................................................................................. 158 2. Frozen Evaporator Coil................................................................................ 159 A. Low Indoor Airflow............................................................................... 160 B. Low Refrigerant Charge...................................................................... 161 C. Liquid Line Restriction......................................................................... 162 D. The Result of a Frozen Evaporator Coil............................................. 164 3. Overcharged System..................................................................................... 165 A. Overcharged System With a TXV....................................................... 166 B. Overcharged System With a Fixed Orifice.......................................... 167 4. Excessive High Side Pressure...................................................................... 169 5. Contaminated Refrigerant............................................................................. 170 6. Weak Compressor Valves or a Bad Reversing Valve................................... 172 A. Weak Compressor Valves or a Weak Internal Pressure Relief Valve. 172 B. Reversing Valve Not Sealing or Moving Properly............................... 173 7. TXV Probtems..................................... ... ................ .... .................. ................. 174 A. TXV Metering Device has Lost Refrigerant Charge from the Bulb, is Clogged, or is Stuck in the Closed Position .................................... 174 B. TXV Bulb is Not Insulated, is Only Loosely Attached to the Vapor Line, or is Not Attached to the Vapor Line at All.. ............................... 176 8. Troubleshooting Guide............................................................................................ 177 Chapter 14. Poor Installation or Design Problems that May be Encountered ........... 1. Improper Metering Device for the Refrigerant in the System........................ 2. Improperly Sized Metering Device or Evaporator Coil ................................. 3. Finding Target Superheat in a Dry Climate................................................... 4. Acidic Refrigerant. .........................................................................................

179 179 179 181 182

Chapter 15. Troubleshooting Low Airflow Problems................................................. 1. Measuring CFM... ... ........ .......................... ....... .. ........................... ... ........... .. 2. The Temp Rise Formula for Each Fuel Source............................................ 3. Additional Methods for Measuring CFM. ............................. ................... ...... A. Flow Capture Hood............................................................................. B. Rotating Vane Anemometer................................................................ C. Traversing the Duct............................................................................ D. Timed Inflation..................................................................................... 4. Static Pressure............................................................................................. A. TESP (Total External Static Pressure)................................................. B. TESP Test Points ................................................................................................... C. Pressure Drop Across Components.................................................... D. Test Points for a Filter.......................................................................... E. Test Points for an Evaporator Coil......................................................

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0 0 Chapter 16. Metering

Devices................................................................................... 1. What is a Metering Device?.......................................................................... 2. Capillary Tube Metering Device.................................................................... 3. Piston Metering Device....................................................................................... 4. TXV (Thermostatic Expansion Valve) Metering Device................................ A. The Sensing Bulb Pressure (P1 )........................................................ B. The Equalizer Pressure (P2 ). ............ ......... .... .... ... ........ ..................... C. The Spring Pressure (P3 ).. ... .. ... ...... ....... .. ..... ...... .... ... .... ................... D. TXV Pressures.................................................................................... E. TXV Bulb Location.............................................................................. 5. EEV (Electric Expansion Valve)................................................................... 6. AEV (Automatic Expansion Valve)............................................................... 7. Advantages to Using a TXV Compared to a Fixed Orifice............................ A. TXV Efficiency..................................................................................... B. Charging Method ................................................................................. C. Initial Heat Removal. ........................................................................... D. Low Airflow Situation........................................................................... 8. How Can the TXV Go Bad?.......... ................................................................ 9. The Diagnosis of a Faulty TXV.....................................................................

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HVAC System Components.................................................................. 206 a 1. Compressors and Refrigerant Oil................................................................. 206 a A. Rotary Compressor......................................... ,. ..................................... 207 B. Reciprocating Compressor.................................................................. 208 a C. Scroll Compressor.............................................................................. 208 a D. Refrigerant Oil. .................................................................................... 209 a 2. Filter Drier...................................................................................................... 211 a 3. Line Set........................................................................................................ 213 a A. Line Set Insulation.............................................................................. 214 a B. Residential Line Set Sizes.................................................................. 215 a C. Refrigerant Weight Per Foot of Line Set............................................ 216 4. Evaporator and Condenser........................................................................... 217 a 5. Suction Line Accumulator............................................................................. 218 a 6. Reversing Valve............................................................................................. 219 0 7.Receiver......................................................................................................... 222 0

Chapter 17.

Appendix A: System Heat Removal Capacity............................................................. 224 a Appendix B: Heat Load and Loss Calculations.......................................................... 225 a Appendix C: Blend Refrigerants... ".,..,.. 228 a 0 1. Blend Types........... "··········"····"·································· . ···································· 228 2. Fractionation................................................................................................. 229 a 3. Bubble and Dew........................................................................................... 229 0 u

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Introduction The concepts and practices illustrated in this book provide a thorough base of knowledge that applies to HVACR service and installation. Specific topics include the refrigeration cycle, superheat and subcooling charging procedures, system preparation for refrigerants, and diagnosis of problems. Also included is a practical approach that details the use of specific tools and supplies for maintenance, diagnosis, and repair. Safety glasses, butyl lined gloves, and other PPE (Personal Protective Equipment) must be worn prior to and while performing procedures.

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CHAPTER 1 Understanding Refrigerants and the Refrigeration Cycle 1. The Refrigeration Cycle

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In refrigerators, freezers, homes and almost any place that we visit or work, the refrigeration cycle is used to transport heat from one location to another. In most cases, the cycle is used to reduce temperature and/or humidity in an area, but it can also be used to increase temperature. In the refrigeration cycle, the refrigerant is the fluid used to transfer heat from one part of the refrigeration system to the other. In a cooling system, the refrigerant absorbs heat from air, occupants, and/or objects and transports the heat to an outside environment to reject it. Figure 1-1 shows a very basic refrigeration cycle along with the pressure, state, and temperature of the refrigerant at each point. High Pressure, High Temperature, Vapor

Low Pressure, Low Temperature, Vapor

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Figure 1-1: Basic RefrigeraUon Cycle

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a 2. Refrigerants Used in the Refrigeration Cycle Many types of refrigerant exist on the market today. Refrigerants vary in toxicity, flammability, environmental friendliness, availability, and cost. The majority of refrigerants currently in use have been developed to be less toxic and less flammable than other chemicals which can be used as refrigerants. The development of new refrigerants is ongoing. Refrigerants are developed to boil and condense at certain temperatures so that they are useful and efficient for each specific application. The three most well-known and largely used refrigerants are Chlorine Fluorine Carbon (CFC), Hydrogen Chlorine Fluorine Carbon (HCFC), and Hydrogen Fluorine Carbon (HFC).

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CFC (Chlorine Fluorine Carbon) is also known as Chlo- a rofluorocarbon. One example of CFC refrigerant is R-12 which a was used in cars, refrigerators, and commercial refrigeration 0 units. See Figure 1-2 for an R-12 refrigerant bottle. 0

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Figure 1-2: R-12

HCFC (Hydrogen Chlorine Fluorine Carbon) is also a known as Hydrochlorofluorocarbon. One example of an HCFC 0 refrigerant is R-22 which was used in cars, residential and a commercial air conditioning units, and refrigeration units. See a Figure 1-3 for an R-22 refrigerant bottle. a

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Figure 1-3: R-22

HFC (Hydrogen Fluorine Carbon) is also known as Hydrofluorocarbon. One example of an HFC refrigerant is R-134A which is used in cars and refrigeration units. Another example is R-41 OA which is used in residential and commercial air conditioning units. See Figure 1-4 for an R-41 OA refrigerant bottle. Figure 1-4: R-410A

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CHAPTER 1: Understanding Refrigerants and the Refrigeration Cycle

Newer refrigerants continue to be developed because research indicates that there are environmental impacts associated with existing refrigerants. CFC refrigerants were one of the first widely used refrigerants that were specifically designed for refrigeration systems. CFC's, however, have a very high ODP (Ozone Depletion Potential). They also have GWP (Global Warming Potential). Both of these factors have a negative impact on environmental friendliness. ODP leads to a larger hole in the earth's ozone layer. GWP is rated by the level of greenhouse gases that make the earth warmer. HCFC refrigerants have the second highest ODP and also have GWP. The release of chlorine based refrigerants into the atmosphere is a major cause of ozone depletion. HFC refrigerants do not have any chlorine, and therefore have no ODP. However, HFC's have GWP. Research is presently under way to develop refrigerants which will minimize the greenhouse effect while maintaining zero ODP and an effective heat transfer rate at a specific boiling point for each refrigerant. At the same time, HVACR systems need to be engineered for these types of refrigerants for longevity and electrical efficiency. HFO (Hydrofluoroolefin) refrigerants, HFC refrigerants with low GWP, and Natural Refrigerants are being developed and used to meet the goal of environmental friendliness. Two trade-offs of using these refrigerants are that some have a higher flammability rating than traditional refrigerants and some are more limited in their scope of use. Natural Refrigerants have no ODP and the lowest GWP of any refrigerant.

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Two examples of a Natural Refrigerant are R-290 (Propane) and CO2 (Carbon Dioxide). They have no chlorine to affect ODP and no fluorine to affect GWP. R-290 is an HC (Hydrocarbon) refrigerant. All HC refrigerants are highly flammable. HC refrigerants are typically used in applications where the equipment has additional safety sensors and considerationst or in applications where a very small amount of refrigerant is needed inside the equipment. CO2 on the other hand, is a Natural Refrigerant that is nonflammable and has a limited scope of use due to its triple point and critical point. This means that the refrigerant states which are the most useful for heat transfer are more limited due to temperature or pressures available. For equipment applications where CO2 meets operating condition guidelines, it can be a very efficient refrigerant choice.

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CHAPTER 1: Understanding Refrigerants and the Refrigeration Cycle

3. Explanation of Section 608 Certification EPA Section 608 regulations are used in the United States of America to regulate who can buy and work with refrigerants, and how this work will be performed. Individuals who violate EPA Section 608 regulations may lose their Section 608 certification, be fined, and/or assigned jail time. Each fine is assigned per occurrence, per day, and can cost $44,539 or more. This information can be found through www.epa.gov. Testing agencies have been approved to administer the "Section 608" and "Section 609" certification exams in order to certify an individual within the United States of America to purchase and to work with regulated refrigerants. Section 608 covers certification for MVAC-like (such as off road vehicles), Non-MVAC (such as aircraft, trains, refrigerated trailers, ships and boats), and stationary refrigeration and air conditioning appliances and equipment. Section 609 covers certification for MVAC (Motor Vehicle Air Conditioners) and MVAC-like equipment. Below is a quick description of each EPA Section 608 certification, but the information is subject to change. Individuals should go directly to the source at www.epa.gov/section608 which will have the most current information which supersedes any statements in this book. Individuals can also check with testing organizations for clarification.

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Type I Certification; The technician may service or dispose of appliances with 5 lb or less of refrigerant that are packaged and sealed by the factory. The technician 0 is awarded this certification after passing the Core and Type 1 test sections only. a An example of a Type 1 unit is a packaged refrigerator or freezer with less than 5 lb 0 of refrigerant. 0

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Type II Certification: The technician may service or dispose of appliances that are O medium, high, or very high pressure. The technician is awarded this certification a after passing the Core and Type 2 test sections only. One example of a Type 2 a unit is a refrigeration split system with 2 lb of refrigerant that is installed together in the field. Another example is a packaged air conditioning system with 14 lb of a R-22 refrigerant. A third example is a split system air conditioner that has 60 lb of 0 R-41 OA refrigerant. a

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CHAPTER 1: Understanding Refrigerants and the Refrigeration Cycle

Type

Ill Certification:

The technician may service or dispose of appliances that are low pressure. The technician is awarded this certification after passing the Core and Type 3 test sections only. An example of a Type 3 unit is a centrifugal chiller system with 200 lb of refrigerant in which the low side pressure is lower than atmospheric pressure while running. Universal Certification: This allows the technician to service and dispose of appliances in Type I, Type 11, and Type Ill categories and to buy any refrigerants necessary for service and installation. The technician is awarded this certification after passing the Core, Type I, Type 11, and Type Ill test sections. Figure 1-5 shows an example of a Universal 608 Certification from a testing organization.

THE CEUAUTHORITY ~ EPA Section 608 Certification

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Figure 1-5: EPA 608 Universal Certification Card (Courtesy of The CEU Authority)

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A technician who has earned a Universal 608 Certification has passed all four parts of the certification test which are the Core, Type I, Type 11, and Type 111 sections. Each section usually contains 25 questions for a total of 100 test questions. The test is usually completed in front of an approved proctor at a testing center. Rather than testing at a testing agency, some testing agencies allow the test to be completed online. The results of the online test are usually available to the individual immediately after the test is completed. This depends on the actual testing agency administering the test. The result of the paper test is not immediately available upon completion of the test because the test has to be shipped back to the testing agency to be graded. There are multiple organizations to test through in order to become EPA 608 certified. A complete list of all approved testing organizations can be found through www.epa.gov/section608 .

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CHAPTER 1: Understanding Refrigerants and the Refrigeration Cycle

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4. The Saturated State of a Refrigerant

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In air conditioning and refrigeration, technicians use terms such as heat 0 absorption, heat rejection, and heat removal instead of "making something cold" or 0 "the coolness of an object". In the absence of heat, a room feels cold. Cold is felt a while the removal of heat is what is happening. For example, in a refrigerator, the CJ refrigerant absorbs the heat and moves the heat outside to reject it. This results a in heat removal and a lowering of the temperature inside the refrigerator. This probably differs from what most people heard while growing up when they talked a about refrigerators, air conditioners and the outside air. a

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Figure 1-6: Ice Cube Melting

Refrigerants, like water, have multiple states - solid, liquid, and gas. Similar to other refrigerants, it takes a large amount of BTU (British Thermal Unit) of heat to change water from one state to another. The amount of BTU needed to change water from one state to another is dramatically higher than the BTU needed to raise the temperature of water while it remains in the same state. This means that the act of changing a medium from one state to another provides the ability to store and reject a large amount of heat which would otherwise be unattainable without the changing of states. Figure 1-6 shows an ice cube melting which is a change of state.

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TXV Metering Device at the Indoor Coil = Subcoollng Charging Method The Target Subcooling = 12° F Red High Side Gauge Pressure Converted to Sat Temp = 102° F High Side Liquid Line: Actual Temp T1 = 96° F Sat Temp - Actual Temp = Subcooling 102° F - 96° F = 6° F of Actual Subcooling 6° F Actual Subcooling < 12° F Target Subcooling = Low Refrigerant Charge

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CHAPTER 8: Charging and Recovery of Refrigerant

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Since the calculated output is 71,250 BTU/HR, the 75,000 BTU/HR furnace will work for this installation. If the furnace has a two speed or modulating gas valve, then the furnace will be more energy efficient during conditions where there is less of a heat loss since the furnace can ramp down to a lower fuel usage. The furnace blower motor capacity also needs to match or exceed the heat removal 0 0 capacity.

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For heat removal in this case, the technician must choose a unit that has a capacity of 29,000 BTU/HR or slightly higher. Since most residential split air 0 conditioning systems range from 18,000 BTU/HR to 48,000 BTU/HR of heat a removal capacity in 6,000 BTU/HR increments, the unit size will need to be 30,000 O BTU/HR. The indoor coil, metering device, blower motor, and outdoor unit need to match this capacity. The blower motor in a furnace may have a higher capacity a than what is needed, but the speed can usually be adjusted to run at a matched a capacity. This is because most blower motors are multi-speed or variable speed. a

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The equipment capacity selected must meet or slightly exceed the building's a heat load and loss calculations unless energy conservation measures are done to a the building. These measures can reduce the heat load and loss figures moving forward. Such measures include air sealing, higher insulation levels, insulation 0 encapsulation, ventilation, replacement of windows and doors with lower U-values, 0 and other renovations. 0 Computer programs make it easy to calculate the heat load and loss of a building. Calculations may also be done with manual forms. On site investigation and/or architectural drawings are needed to determine building location, orientation, and other factors.

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APPENDIXB

At a minimum the following data is needed in order to formulate a heat load and loss calculation: • • • • • • • •

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commercial or residential use maximum occupancy zip code design temperatures volume of the building gross exterior walls inside finishing and outside sheathing, insulation R-value exterior door and window sizes and U-value, orientation, leakage, glass type and frame type skylight U-value, orientation, glass type and frame type floor dimensions, type of flooring insulation value underneath, and if there Is any ventilation underneath ceiling dimensions, ceiling type, rafter height, insulation value, ventilation above, encapsulation, and if the ceiling is a cathedral lighting specifications for heat offset appliances for heat offset tightness of the building room sizes and percentage of the load or loss location of the duct, whether inside or outside the structure, or in the attic or crawlspace, as well as insulation value, and leakage mechanical ventilation, if used

A recognized heat load and loss calculation form or software should be used. An HVAC installation or service company may purchase a heat load and loss form or computer program, may use a program through a manufacturer, or in some cases have their local material supplier develop the calculations for them by providing them with the on site data. Material suppliers may or may not be willing or able to provide this service to customers.

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APPENDIXC

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Appendix C: Blend Refrigerants

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1. Blend Types

Refrigerants used in some systems may be made up of a mix of two or more O single component refrigerants. They are combined at the factory to make a new a refrigerant called a blend refrigerant. Blend refrigerants can either be Azeotropic, O Near-Azeotropic, or Zeotropic. O

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Azeotropic means that the refrigerants in the blend behave like they are a 0 single component refrigerant. Because of this, a standard PIT chart can be used a a when working with an Azeotropic refrigerant.

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Near-Azeotropic means that the boiling point of each single component refrigerant is very close to the others' but not the same. Because of this, a bubble and dew PIT chart is used for most Near-Azeotropic refrigerants since the dew point (saturated temp in the evaporator prior to superheating) and the bubble point (saturated temp in the condenser prior to subcooling) are slightly different. However, in the case of R-41 OA and some other blend refrigerants with a very minimal temperature glide, a standard PIT chart can be used. Zeotropic means that the boiling point of each single component refrigerant is different. A bubble and dew PIT chart is used for Zeotropic refrigerants since the dew point (saturated temp in the evaporator prior to superheating) and the bubble point (saturated temp in the condenser prior to subcooling) are different. Zeotropic refrigerants have a high temperature glide.

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The temperature swing between the boiling point and condensing point of 0 a Near-Azeotropic or Zeotropic refrigerant at a constant pressure is known as the "temperature glide". The temperature glide is due to each single component a refrigerant (that makes up the blend refrigerant) having a different boiling point. a The temperature glide incorporates the amount of degrees it takes for all of the 0 single component refrigerants to finish changing states. This range is from the dew 0 a point to the bubble point.

0 The three things to consider when working with Zeotropic refrigerants are the 0 potential for fractionation if there is a leak, the need for the bubble and dew P/T 0 chart, and that the refrigerant must be charged from the bottle into the system as 0 a liquid, in order to maintain a pure mix. 0 0

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APPENDIXC

2. Fractionation Fractionation is the potential for a single component refrigerant within a blend refrigerant to leak out faster than the other single component refrigerant(s) due to the mixture of the blend when it is in the vapor state. Any leakage during this state will change the intended composition of the refrigerant blend. During a leak, the severity of the change within the mixture depends on whether the unit is mainly running or mainly off during the leakage. If the unit is running, then it is more likely that the refrigerant blend will circulate through the system in the correct mix and therefore leak each single component refrigerant at a more even rate. This leaves mostly a correct mix in the system. If the leak occurs when the system is mainly off, the refrigerant with the highest pressure wilt leak out faster than the other single component refrigerant(s). In this case, nothing can be done with the existing refrigerant charge and the technician will need to recover the existing bfend. New virgin refrigerant must be weighed back in after fixing the leak, pressure testing, and using proper vacuum procedures. Fractionation may not apply or be severe when referring to R-41 OA as the two single component refrigerants that make up R-41 OA (R-32 and R-125) are Near-Azeotropic. In some cases, however, it is best to recover all of the R-41 OA refrigerant and weigh in new virgin refrigerant after fixing the leak. This can be done to guarantee the best system efficiency. Refrigerant is weighed from the bottle into the system as a liquid since the mixture will stay at the correct composition while in the liquid state.

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Since Zeotropic refrigerants have a temperature glide, the bubble and dew saturated temps must be found on a PIT chart, calculator, digital manifold set, or app in order to check the refrigerant charge. When checking the subcooling of a Zeotropic refrigerant, the technician must convert the pressure read on the liquid line to the saturated bubble temp. The saturated bubble temp minus the actual temp on the liquid line is the subcooling. When checking the total superheat of a Zeotropic refrigerant, the technician must convert the pressure read on the vapor line to the saturated dew temp. The actual temp on the vapor line minus the saturated dew temp is the total superheat.

.._ Blend Refrigerant Total Superheat = Actual Temp on Vapor Line - Saturated Dew Temp ._ L Blend Refrigerant Subcooling = Saturated Bubble Temp - Actual Temp on Liquid Line L

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