HVAC Troubleshooting Guide

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HVAC Troubleshooting Guide

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HVAC Troubleshooting Guide Rex Miller

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Copyright © 2009 by The McGraw-Hill Companies, Inc. All rights reserved. Except as permitted under the United States Copyright Act of 1976, no part of this publication may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without the prior written permission of the publisher. ISBN: 978-0-07-160507-6 MHID: 0-07-160507-X The material in this eBook also appears in the print version of this title: ISBN: 978-0-07-160499-4, MHID: 0-07-160499-5. All trademarks are trademarks of their respective owners. Rather than put a trademark symbol after every occurrence of a trademarked name, we use names in an editorial fashion only, and to the benefit of the trademark owner, with no intention of infringement of the trademark. Where such designations appear in this book, they have been printed with initial caps. McGraw-Hill eBooks are available at special quantity discounts to use as premiums and sales promotions, or for use in corporate training programs. To contact a representative please visit the Contact Us page at www.mhprofessional.com. Information contained in this work has been obtained by The McGraw-Hill Companies, Inc. (“McGraw-Hill”) from sources believed to be reliable. However, neither McGraw-Hill nor its authors guarantee the accuracy or completeness of any information published herein, and neither McGraw-Hill nor its authors shall be responsible for any errors, omissions, or damages arising out of use of this information. This work is published with the understanding that McGraw-Hill and its authors are supplying information but are not attempting to render engineering or other professional services. If such services are required, the assistance of an appropriate professional should be sought. TERMS OF USE This is a copyrighted work and The McGraw-Hill Companies, Inc. (“McGraw-Hill”) and its licensors reserve all rights in and to the work. Use of this work is subject to these terms. Except as permitted under the Copyright Act of 1976 and the right to store and retrieve one copy of the work, you may not decompile, disassemble, reverse engineer, reproduce, modify, create derivative works based upon, transmit, distribute, disseminate, sell, publish or sublicense the work or any part of it without McGraw-Hill’s prior consent. You may use the work for your own noncommercial and personal use; any other use of the work is strictly prohibited. Your right to use the work may be terminated if you fail to comply with these terms. THE WORK IS PROVIDED “AS IS.” McGRAW-HILL AND ITS LICENSORS MAKE NO GUARANTEES OR WARRANTIES AS TO THE ACCURACY, ADEQUACY OR COMPLETENESS OF OR RESULTS TO BE OBTAINED FROM USING THE WORK, INCLUDING ANY INFORMATION THAT CAN BE ACCESSED THROUGH THE WORK VIA HYPERLINK OR OTHERWISE, AND EXPRESSLY DISCLAIM ANY WARRANTY, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. McGraw-Hill and its licensors do not warrant or guarantee that the functions contained in the work will meet your requirements or that its operation will be uninterrupted or error free. Neither McGraw-Hill nor its licensors shall be liable to you or anyone else for any inaccuracy, error or omission, regardless of cause, in the work or for any damages resulting therefrom. McGraw-Hill has no responsibility for the content of any information accessed through the work. Under no circumstances shall McGraw-Hill and/or its licensors be liable for any indirect, incidental, special, punitive, consequential or similar damages that result from the use of or inability to use the work, even if any of them has been advised of the possibility of such damages. This limitation of liability shall apply to any claim or cause whatsoever whether such claim or cause arises in contract, tort or otherwise.

ABOUT THE AUTHOR Rex Miller is professor emeritus of industrial technology at State University of New York college at Buffalo and has taught technical curriculum at the college and high school levels for more than 40 years. He is the coauthor of McGraw-Hill’s best-selling Carpentry & Construction, now in its Fourth Edition, and the author of more than 100 texts for vocational and industrial arts programs. He lives in Round Rock, Texas.

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Contents

Preface xxi Acknowledgments

xxiii

Chapter 1. Tools and Instruments Tools and Equipment Pliers and clippers Fuse puller Screwdrivers Wrenches Soldering equipment Drilling equipment Knives and other insulation-stripping tools Meters and test prods Tool kits Gages and Instruments Pressure gages Gage selection Line pressure Effects of temperature on gage performance Care of gages Gage recalibration Thermometers Pocket thermometer Bimetallic thermometer Thermocouple thermometer Resistance thermometer Superheat thermometer Superheat Measurement Instruments Halide Leak Detectors Setting up Lighting Leak testing the setup Adjusting the flame Detecting leaks Maintenance

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Electrical Instruments Ammeter Voltmeter Ohmmeter Multimeter Wattmeter Other Instruments Air-filter efficiency gages Air-measurement gages Humidity-measurement instruments Stationary psychrometers Moisture analyzers Btu meters Vibration and sound meters Service Tools Special Tools Vacuum Pumps Vacuum pump maintenance Vacuum pump oil problems Operating instructions Evacuating a system Charging Cylinder Charging Oil Changing Oil Mobile Charging Stations Tubing Soft copper tubing Hard-drawn copper tubing Cutting copper tubing Flaring copper tubing Constricting tubing Swaging copper tubing Forming refrigerant tubing Fitting copper tubing by compression Soldering Soft soldering Silver soldering or brazing Testing for Leaks Cleaning and Degreasing Solvents New and Old Tools

Chapter 2. Heat Pumps and Hot-Air Furnaces Hot-Air Furnaces Basic Gas Furnace Operation Basic Electric Heating System Basic operation Ladder Diagrams Manufacturer’s Diagrams Field Wiring Low-Voltage Wiring Thermostat location Printed circuit board control center

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Heat Pumps Operation Special requirements of heat-pump systems Heat-pump combinations High-Efficiency Furnaces Operation Electrical controls Sequence of operation Combustion process Troubleshooting the Lennox Pulse Furnace

Chapter 3. Ventilation Requirements Air Leakage Natural Ventilation Wind forces Temperature-difference forces Combined wind and temperature forces Roof ventilators Ventilator capacity Fresh-Air Requirements Mechanical Ventilation Volume of air required Duct-system resistance Air Filtration Effect of dust on health Various dust sources Air-Filter Classification Dry filters Wet (or viscous) filters Filter Installation Humidity-Control Methods Humidifiers Air-washer method Pan humidifiers Electrically operated humidifiers Air-operated humidifiers Dehumidifiers Electric dehumidification Controls Adsorption-type dehumidifiers Air-Duct Systems Heat gains in ducts Resistance losses in duct systems Fans and Blowers Air volume Horsepower requirements Drive methods Fan selection Fan applications Fan operation Attic-fan installation Attic-fan operation

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Chapter 4. Refrigeration Historical Development Structure of Matter Elements Atom Properties of Matter Pressure Pressure-indicating devices Pressure of liquid and gases Atmospheric pressure Gage pressure Absolute pressure Compression ratio Temperature and Heat Specific heat Heat content Other sources of heat Refrigeration Systems Refrigeration from vaporization (open system) Basic refrigeration cycle Capacity Refrigerants Refrigerant replacements and the atmosphere

Chapter 5. Refrigerants: New and Old Classification of Refrigerants Common refrigerants Freon Refrigerants Molecular weights Flammability Toxicity Skin effects Oral toxicity Central nervous system (CNS) effects Cardiac sensitization Thermal decomposition Applications of Freon Refrigerants Reaction of Freon to Various Materials Found in Refrigeration Systems Metals Plastics Refrigerant Properties Pressure Temperature Volume Density Enthalpy Flammability Capability of mixing with oil Moisture and refrigerants Odor Toxicity Tendency to leak

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Detecting Leaks Sulfur dioxide Carbon dioxide Ammonia Methyl chloride Ban on Production and Imports of Ozone-Depleting Refrigerants Phaseout Schedule for HCFCs, Including R-22 Availability of R-22 Cost of R-22 Alternatives to R-22 Servicing existing units Installing new units Servicing your system Purchasing new systems Air-Conditioning and Working with Halon General information Leak Repair Trigger rates When additional time is necessary Relief from retrofit/retirement System mothballing EPA-Certified Refrigerant Reclaimers Newer Refrigerants Freon Refrigerants Classifications Properties of Freons Refrigerant Characteristics Critical temperature Latent heat of evaporation Specific heat Power consumption Volume of liquid circulated Handling Refrigerants Storing and handling refrigerant cylinders Lubricants R-134a Refrigerant R-134a applications R-12 Systems—General Considerations R-12 medium-high-temperature refrigeration (>0ⴗF evaporation) R-12 low-temperature refrigeration (