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This website explains in detail the inspection, troubleshooting diagnosis, and repair of all types of residential and light commercial central air conditioning and heat pump systems. This article describes how to inspect and repair all types of residential air conditioning systems (A/C systems). Information for home buyers, owners, and home inspectors about A/C or heat pump system problems. If you don't see information you want, ask us for it using the comments box at the end of this article.

Page top illustration of a heat pump schematic is provided courtesy of Carson Dunlop Associates and is found in their Home Reference Book. A somewhat simpler schematic of an air conditioning-only system is provided just below.
Srpski prevod nad današji stranica [Serbian translation]

This article series describes the basic components of an air conditioning system and then we discuss how to estimate the rated cooling capacity of an air conditioning system by examining various data tags and components. The limitations of visual inspection of A/C systems are described. We continue to add to and update this text as new details are provided. Contact us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution.

If your air conditioner or heat pump system is not working, start at LOST COOLING CAPACITY for help in diagnosing and repairing the trouble.

© Copyright 2012 InspectAPedia.com, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use page top links to major topics or use links at the left of each page to navigate within topics and documents at this website. Green links show where you are in a document series or at this website.

All the detail about air conditioning you want is provided here - CONTACT us if you can't find something. Let's introduce the most basic concepts of air conditioning first:

What are the Parts of an Air Conditioning or Heat Pump System and How do Air Conditioners Work?

Here is a simple explanation of how an air conditioning system works, with enough detail so that it isn't simply magic (the schematic of an air conditioner shown at left is compliments of Carson Dunlop) A detailed list and photos of air conditioner components can be seen at AIR CONDITIONER COMPONENT PARTS.

1. A air conditioning or heat pump compressor which compresses low pressure refrigerant gas into a high pressure, high temperature gas. Usually the compressor is in the outdoor portion of an air conditioning or heat pump system. The compressor is basically a high pressure pump driven by an electric motor. The air conditioning compressor is usually packaged in the outdoor compressor/condenser unit illustrated by our page top drawing. See COMPRESSOR CONDENSER, and see REFRIGERANTS
   
   
2. A condenser or condensing unit: typically a condensing coil inside which high temperature high pressure refrigerant gas flows, and over which a fan blows air to cool the refrigerant gas back to a liquid state (thus transferring heat from the refrigerant gas to the air being blown by the fan). The condenser unit is basically a coil of finned tubing and a fan to blow air across the coil. Usually the condenser unit is in the outdoor portion of an air conditioning system, often packaged along with the compressor motor discussed above. See COMPRESSOR CONDENSER and see our page top sketch too. The change of state of the refrigerant, from hot high pressure gas to a liquid releases heat, including heat collected inside the building) to the outdoors.
   
   
3. A metering device which dispenses liquid refrigerant into an evaporator coil. The metering device may be simply a thin section of tubing (a capillary or "cap" tube) or it may be a bit more sophisticated thermostatic expansion valve (TEV) which includes a temperature sensing control that can open and shut the device against refrigerant flow. See THERMOSTATIC EXPANSION VALVES or see CAPILLARY TUBES.
   
   
4. An evaporator coil or cooling coil: typically the cooling coil is a section of finned tubing (it looks a lot like a car radiator) into which liquid refrigerant is metered and permitted to evaporate from liquid to gas state inside the coil. This state change of the refrigerant, from liquid to gas, absorbs heat, cooling the evaporator coil surface and thus cooling indoor air blown across the cooling coil. Usually the cooling coil is located inside the air handler. See AIR HANDLER / BLOWER UNITS and articles like DIRTY COOLING COIL. Evaporative cooling systems, or swamp coolers are discussed separately at EVAPORATIVE COOLING SYSTEMS.
   
   
5. An air handler and blower unit which provides a fan to blow building air across or through the evaporator coil. The air handler blower fan unit moves building air across the evaporator coil surface in order to condition building air by cooling it (and thus also by removing moisture from the cooled air). See AIR HANDLER / BLOWER UNITS and BLOWER FAN OPERATION & TESTING.
   
   
6. A duct system which distributes conditioned air from the air handler in to the occupied space (supply ducts), and which takes air from the occupied space and returns it to the cooling system air handler. See DUCT SYSTEM
   
   
7. Heat Pump Systems use the same components we have described just above, with the addition of a reversing valve that in essence permits the system to run "backwards" in cold weather. So in air conditioning mode the heat pump is moving heat from inside the building to outdoors while in heating mode the heat pump is moving heat from outdoor air (or water in some designs) to the building interior. Because the ability of a heat pump to extract heat from outdoor air diminishes at low outdoor temperatures, heat pump systems in northern climates also include a backup or auxiliary heating system. Details of how heat pumps work, are inspected, diagnosed, and repaired begin at HEAT PUMPS.
   
   
8. Air conditioner controls and features, which include a room thermostat, electrical switches, fuses or circuit breakers, condensate handling system, and air filters. See OPERATING CONTROLS and AIR FILTERS for HVAC SYSTEMS
   

For photographs of these various air conditioning and heat pump parts, and for an explanation of where these air conditioning components are physically located, see A/C COMPONENTS which discusses  Indoor A/C Components and Outdoor A/C Components

How to diagnose and fix an air conditioning system that is not working: list of diagnostic articles

Since the failure of an air conditioner to turn on, loss of air conditioner cooling capacity, reduced air conditioning output temperatures, loss of cool air supply, or even loss of air flow entirely can be due to a variety of problems with one or more components of an air conditioner or air conditioning system, after reviewing the lost air conditioner cooling diagnosis procedures described in this article, be sure to also review the diagnostic procedures at each of the individual air conditioning diagnosis and repair major topics listed just below. To return to our air conditioning and refrigeration home page go to AIR CONDITIONING & HEAT PUMP SYSTEMS.

Electrical problems on HVAC systems: Keep in mind that despite the depth of technical detail you will find here about all components of air conditioners and heat pumps, most service calls for non-working air conditioners or heat pumps turn up an electrical problem. So if your A/C system is just not working at all be sure to check all of our electrical and control setting suggestions first.

Mechanical problems on HVAC systems: tend to fall into these groups: refrigerant leaks, dirty condenser coil or unit, dirty evaporator or cooling coil, or burned out (or hard-starting) compressor motors. We have also seen a number of problems with fans and fan motors in both the compressor/condenser unit and in the air handler/blower fan unit. Some of those fan problems are mechanical - like a loose fan belt or blade.

If your air conditioning or heat pump system has completely lost cooling capacity or if it plain won't start you can jump right to AIR CONDITIONER NOT WORKING or select one or more of the diagnostic articles listed below.

• A/C REFRIGERANT LEAK DETECTION: how to use a TIF5000 to detect air conditioning refrigerant gas leak. Also see   REFRIGERANT LEAK DETECTION and  REFRIGERANT LEAK REPAIR and REFRIGERANT PIPING & DISTANCES
• A/C DIAGNOSTIC FAQs: air conditioning system diagnostic FAQs: Q&A about air conditioner repair - a detailed air conditioning system diagnostic checklist
• AIR HANDLER UNIT: problems with the air handler, air filters, and the cooling coil itself
• BACKUP HEAT: on heat pumps, types of backup heat; problems with backup heat; begin here if your heat pump is not providing enough heat or if your air conditioning system provides heat when it should be providing cooling.
• Blower Fan AUTO ON controls for air conditioning or heating blower fan units
• BLOWER FAN OPERATION & TESTING: problems with the blower fan on furnaces, heat pumps, and air conditioners
• COMPRESSOR CONDENSER: problems with air conditioner compressor/condenser units
  • COMPRESSOR & CONDENSING COIL, A/C
      BURNED-OUT COMPRESSOR - how do we diagnose a burned out compressor motor?
      CAPACITORS for HARD STARTING MOTORS - diagnose, install, replace an air conditioner motor starter capacitor
      CONDENSING COIL REPAIR REPLACE
      CONTACTOR RELAY DIAGNOSIS & REPAIR
      CONTROL CIRCUIT BOARD, A/C
      FAN, COMPRESSOR/CONDENSER UNIT
      HARD STARTING COMPRESSOR MOTORS - cause and cure of hard starting air conditioner compressors
      INSPECTION CHECKLIST - OUTDOOR UNIT
      INSTALLATION ERRORS, COMPRESSORS
      LONG-ON CYCLING AC COMPRESSOR
      MOTOR OVERLOAD RESET SWITCH - where to find some "hidden" reset switches to get your A/C going again
      NOISES, COMPRESSOR CONDENSER
      Pressure Controls & Safety Switches
      PRESSURE READINGS, COMPRESSOR
      REPLACING A COMPRESSOR
      SHORT CYCLING AC COMPRESSOR - diagnose and cure A/C compressor that turns on and off too frequently
      TIGHT or SEIZED AC COMPRESSORS
• A/C - HEAT PUMP CONTROLS & SWITCHES: air conditioner controls and switches - begin here if your A/C won't start. Here's an important tip: most refrigeration problems, in air conditioners, refrigerators, or freezers, are electrical, not mechanical. In air conditioning school, we used to drive out and collect abandoned refrigerators that people were tossing out during our community's spring cleanup week.
  
  Taking these appliances back into the shop we found that almost always the problem that had caused the owner to dispose of their air conditioner or freezer was in an electrical connection or electrical control and some refrigeration class instructions opine that 80% of problems on these systems are electrical in nature. So it's worth checking out switches and controls on an air conditioner before replacing more costly components.
  
  Controls and switches on air conditioners and heat pumps also include THERMOSTATS, circuit breakers, service switches,  CONTACTOR RELAY, refrigerant metering devices such as CAPILLARY TUBES or THERMOSTATIC EXPANSION VALVES, air conditioning or heat pump pressure switches that detect improper high or low pressures and for safety shut off the system, motor overload or motor overheat reset buttons and switches, fan control switches and FAN LIMIT SWITCH, and in some systems automatic duct dampers and ZONE DAMPER CONTROLS.
• Dehumidification Problems - Air conditioner cools but does not dehumidify
• DUCT SYSTEM DEFECTS: problems with the air duct system, air filters, supply registers, return air registers
• ELECTRIC MOTOR DIAGNOSTIC GUIDE - troubleshooting an electric motor
• ENERGY SAVINGS in buildings - complete list of options to make buildings energy efficient
• EVAPORATIVE COOLING SYSTEMS - how can a "swamp cooler" or evaporative cooling system best deliver cool air in a building?
• FAN, AIR HANDLER BLOWER UNIT - diagnose and fix problems with the indoor furnace or air conditioner blower unit fan and fan motor
• FAN, COMPRESSOR/CONDENSER UNIT - diagnose and fix problems with the outdoor compressor/condenser fan and fan motor
• Fire dampers, and Heating and Cooling Air Duct Controls such as manual and automatic duct dampers, zone dampers, and fire dampers are discussed and distinguished at DRAFT REGULATORS - barometric damper
• HEAT PUMPS - diagnosis & repair articles specifically for heat pumps
• LOST COOLING CAPACITY: what to do when not enough cool air comes out of the system
  • What to check first if there is no cool air or not enough cool air
  • Compressor failure diagnosis: checks of the air conditioner compressor
  • Ducts & Air Handler diagnosis: basic checks of the indoor air handler (blower), air ducts, and filter system
  •   A/C Flow Too Weak - weak cool air flow can be caused by several problems, filters, icing, duct leaks, etc.
  •   A/C Filter Problems - dirty or missing filters cause other operating problems
  •   A/C Compressor Problems - quick check
  •   A/C Off - Condensate Pan Switch - some overflow pans have a switch that will shut down the system
  •   A/C Cooling Coil Icing - slow air flow, improper charge, etc. - eventually we get no cooling
  •   A/C Not Dehumidifying - improperly-sized unit, other causes, and cures for lack of dehumidification
  •   A/C Air Duct Problems - leaks, sizing, inadequate return capacity
  •   Air Conditioner Won't Start - various causes including some simple switches to check
  •   Air Conditioner Refrigerant Problems - too much is as bad as too little; leaks, cures.
  •   Blower Fan No Start / No Stop - weird blower behavior can be diagnosed and fixed. See BLOWER FAN OPERATION & TESTING.
  •   Compressor Diagnosis: Diagnose & Repair - serious look into the compressor unit
  •   Cooling Capacity of the Duct System
    
• MANUALS & PARTS GUIDES - HVAC - where to find air conditioner, heat pump, and heating repair manuals, owners guides, installation guides, and parts lists
• OPERATING DEFECTS: major air conditioning problem symptoms and how to get the air conditioning system working again,e.g. compressor or fan noises, failure to start, and inadequate cool air volumes
• REFRIGERANT LEAK DETECTION: how to find and fix air conditioning refrigerant gas leaks. Also see   REFRIGERANT LEAK DETECTION and  REFRIGERANT LEAK REPAIR and REFRIGERANT PIPING & DISTANCES
• SHORT CYCLING AC COMPRESSOR - what causes the air conditioner compressor to keep turning on and off too quickly?
• ZONE DAMPER CONTROLS . discusses manual and automatic air duct zone controls

HVA/C COMPONENT LIST - Air Conditioning & Heat Pump Components Inspection List - the basics

Conventional Residential Air Conditioners: Outside Condenser/Compressor unit, Inside Evaporator Air Handler unit

Conventional cooling systems include the following components: Indoor Components of an air conditioning system (Details can be read and seen at AIR CONDITIONER COMPONENT PARTS) Air Handler Unit (AHU) which typically includes the following [AIR HANDLER / BLOWER UNITS] Air filters - located at return registers or possibly at or in the air handler [AIR FILTERS for HVAC SYSTEMS] Return Plenum Blower fan in a blower compartment [BLOWER FAN OPERATION & TESTING] Evaporator Coil = Cooling Coil [COOLING COIL or EVAPORATOR COIL] Supply plenum Condensate collection & drainage system - CONDENSATE HANDLING, A/C Supply air ducts and registers [DUCT SYSTEM & DUCT DEFECTS] Return air ducts and registers Air filter(s) and possibly other air cleaning/IAQ equipment [AIR FILTERS for HVAC SYSTEMS] Electrical shut off switches, circuit breakers/fuses [CONTROLS & SWITCHES, A/C - HEAT PUMP ] Outdoor Air Conditioning System Components (Details can be read and seen at AIR CONDITIONER COMPONENT PARTS) Compressor motor - on residential units this is normally a hermetic motor-compressor combined in a single sealed unit - COMPRESSOR & CONDENSING COIL, A/C Condensing coil - CONDENSING COIL REPAIR REPLACE Outdoor cooling fan or condenser unit fan - FAN, COMPRESSOR/CONDENSER UNIT Electrical shut-off switch(es) for service & circuit protection - CONTROLS & SWITCHES, A/C - HEAT PUMP All of the components, controls, switches of air conditioning systems and how to diagnose and debug cooling system problems are discussed in detail at this website.

Rooftop Air Conditioning Systems

Wall Convector Heating and Air Conditioning Units

Wall convector heating and cooling units (at left) are often used for both heating and cooling in commercial installations and high-rise apartment buildings. The unit shown has its own compressor mounted right in the cabinet, visible at lower center in the photo. Wall-mounted heating and cooling convector installations may be designed with one central heater or cooling system which feeds multiple units with chilled or heated water or possibly refrigerant from a single remote heating and cooling heat pump. More details: see Wall Convector Units, Heating / Air Conditioning

Split System or Ductless Air Conditioners & Heat Pumps

Another common residential alternative dispenses with duct work entirely, using a wall-mounted indoor evaporator/blower unit and a separate outside compressor/condenser (below left and right). In this split system air conditioning design, one compressor/condenser may serve multiple wall-mount indoor units.

The Sanyo® compressor/condenser unit shown (above left) can support two indoor evaporator/fan cooling units. In this installation the indoor units were mounted in two different areas of the home. The thermostat and controls for split system air conditioners and heat pumps may be wall mounted but often are a portable hand-held remote controller.

More details: see SPLIT SYSTEM AIR CONDITIONERS & HEAT PUMPS.

Goofy Home Made or Do-it-yourself Air Conditioning Systems

Do-It-Yourself Home made air conditioning systems such as this goofy example may actually work but not without problems. This system used a window air conditioner placed in a home's attic. Manhole ventilation duct (liberated from New York City) was used along with a home made hood attached to the air conditioner to blow cool air into the home through a ceiling register. The air conditioning condensate was collected in the blue plastic kiddie pool seen in the photo, and drained by gravity to a plumbing vent stack. Nothing about the system was proper, safe, nor very effective, and in addition, the attic moisture conditions were terrible as you can see from the blackened plywood roof sheathing. Also see: Home Made Air Conditioning Systems

RATED A/C or Heat Pump COOLING CAPACITY - How to Determine Air Conditioning Equipment Rated Cooling Capacity - the basics

Questions & Answers regarding this article

Questions & answers about how to diagnose and repair air conditioning and heat pump systems. If your air conditioner or heat pump system is not working, start at LOST COOLING CAPACITY for help in diagnosing and repairing the trouble.

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Technical Reviewers & References

• InspectAPedia.com^® - Daniel Friedman - Publisher & Editor.
• InspectAPedia Bookstore lists recommended books, organized by topic & available for purchase. Most of our articles also include a list of recommended books for the specific article topic as well as other references, and information sources.
• Critique, contributions wanted: Contact Us to suggest corrections or additions to articles at this website, and if you wish, to receive online listing and credit as a contributor. Particular thanks are due to the many experts and also consumers who read and critique technical articles at InspectAPedia.com.
• Additional technical contributors & reference sources for this article are listed below.

Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

AIR CONDITIONING & HEAT PUMP SYSTEMS

• Thanks to Mark Cramer, Tampa Florida, for assistance in technical review of the "Critical Defects" section and for the photograph of the deteriorating gray Owens Corning flex duct in a hot attic. Mr. Cramer is a Florida home inspector and home inspection educator.
• Thanks to Jon Bolton, an ASHI, FABI, and otherwise certified Florida home inspector who provided photos of failing Goodman gray flex duct in a hot attic.
• Thanks to Scott at SJM Inspect for suggesting this EPA document and for technical editing remarks regarding our air conditioning website, SJM Inspection Service LLC, serves the entire state of CT, sjminspect.com 203-543-0447 or 203-877-4774 5/16/07
• Thanks to Joe Panimondo for technical editing, April 2011
• Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. (416) 964-9415 1-800-268-7070 info@carsondunlop.com. Thanks to Alan Carson and Bob Dunlop, for permission to use illustrations from their publication, The Illustrated Home which illustrates construction details and building components. Carson Dunlop provides home inspection education including the ASHI-adopted Home Inspection Training Program (home study course), publications such as the Home Reference Book, report writing materials including the Horizon report writer, and home inspection services. Alan Carson is a past president of ASHI, the American Society of Home Inspectors.
• Carson Dunlop, Associates, Toronto, have provided us with (and we recommend) Carson Dunlop Weldon & Associates' Technical Reference Guide to manufacturer's model and serial number information for heating and cooling equipment ($69.00 U.S.).
• This website discusses these air conditioning and heat pump terms and problems: Air Conditioners: Central Air Conditioning Troubleshooting & Repair Guide: How to Inspect, Diagnose, & Repair Central Air Conditioning: Defects in A/C compressors, air handlers, duct work, and controls. We explain how to inspect & repair central air conditioning systems and for homeowners we also answer basic HVAC questions such as what are the basic air conditioning components? We provide guidance in determining air conditioning cooling capacity & energy efficiency, Troubleshooting air conditioning compressor problems, Diagnosing air conditioning air handler problems, Air conditioning condensate problems, Duct system inspections, defects, repairs, Cleaning air conditioning equipment & A/C refrigerants.
• HVAC brands discussed include but are not limited to: Lennox, American Standard, Amana, Everrest, Goodman, Frigidaire, Coleman and Gibson. Brands of related air handling equipment include Honeywell, Aprilaire, White-Rogers, Broan. Nutone, Fantech, Venmar, Arzel, Hi-Velocity, Vanguard, Wirsbo, Weil McLain, Unico, Heat Link, A.O. Smith, Water Furnace, ClimateMaster, Geo-Excel, Command Aire, Friedrich, LG, Mitsubishi, Sanyo, Hart &
  Cooley, Munchkin, Superstor Ultra, Lochinvar and Knight HVAC equipment.
• HVAC Employment: U.S. Department of Labor website describes HVAC jobs and the employment outlook for HVAC technicians.
• HVAC Education, Training Accreditation agencies: Quoting the U.S. DOL HVAC website above::
  After completing the programs below, new technicians generally need between 6 months to 2 years of field experience before they are considered proficient. Three accrediting agencies have set academic standards for HVACR programs:
  • HVAC Excellence. 1701 Pennsylvania Ave NW, Washington, DC 20006 Tel: (800) 394-5268. Quoting:
    HVAC Excellence is a not for profit organization that has been serving the HVACR industry since 1994. It is our goal to improve competency through validation of the technical education process. By setting standards and verifying that they have been met, we inspire the industry to excel. We know that all of the challenges that face our industry are achievable by continuous improvement in the way that we prepare technicians.
  • National Center for Construction Education and Research, 3600 NW 43rd Street, Bldg. G, Gainesville, FL 32606, Tel: 888.622.3720, Quoting:
    NCCER is a not-for-profit education foundation created to develop industry-driven standardized craft training programs with portable credentials and help address the critical workforce shortage facing the construction industry.
  • The Partnership for Air-Conditioning, Heating, and Refrigeration Accreditation, (PAHRA) 2111 Wilson Blvd., Suite 500 Arlington, VA 22201-3001 (703) 524-8800, Quoting: The Partnership for Air-Conditioning, Heating, Refrigeration Accreditation (PAHRA) is an independent, third party organization that is a partnership between heating, ventilation, air-conditioning and refrigeration (HVACR) educators and the HVACR industry that will award accreditation to programs that have met and/or exceeded industry validated standards. This programmatic accreditation program is the only one that is supported by the major industry associations.
    

Licensure. Heating, air-conditioning, and refrigeration mechanics and installers are required to be licensed by some States and localities. Requirements for licensure vary greatly, but all States or localities that require a license have a test that must be passed. The contents of these tests vary by State or locality, with some requiring extensive knowledge of electrical codes and others focusing more on HVACR-specific knowledge. Completion of an apprenticeship program or 2 to 5 years of experience are also common requirements.

In addition, all technicians who purchase or work with refrigerants must be certified in their proper handling. To become certified to purchase and handle refrigerants, technicians must pass a written examination specific to the type of work in which they specialize. The three possible areas of certification are: Type I—servicing small appliances; Type II—high-pressure refrigerants; and Type III—low-pressure refrigerants. Exams are administered by organizations approved by the U.S. Environmental Protection Agency, such as trade schools, unions, contractor associations, or building groups.

• HVAC Training Courses, Schools: HVAC Technician Training Schools [http://technicianschool.net/hvac-technician-training-schools/], lists thefollowing schools offering technical courses may offer specific training programs for potential careers, including HVAC technicians. Among HVAC schools that website lists are

  • Everest Colleges [http://www.everest.edu],
  • Florida Career College 7891 Pines Blvd Hollywood, FL 33024 http:// www.careercollege.edu/,
  • Lincoln Institute 2299 Vauxhall Road Union, NJ 07083 http:// www.lincolnedu.com/
  • NOTE: when considering an HVAC training course or school, check the HVAC education accrediting associations listed above.
    
    
• [1] "Air Conditioning & Refrigeration I & II", BOCES Education, Warren Hilliard (instructor), Poughkeepsie, New York, May - July 1982, [classroom notes from air conditioning and refrigeration maintenance and repair course attended by the website author]

Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair

• Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
• Complete List of Air Conditioning & Heat Pump Design, Inspection, Repair Books at the InspectAPedia Bookstore.

• Modern Refrigeration and Air Conditioning, A. D. Althouse, C.H. Turnquist, A. Bracciano, Goodheart-Willcox Co., 1982
• Principles of Refrigeration, R. Warren Marsh, C. Thomas Olivo, Delmar Publishers, 1979
• "Air Conditioning & Refrigeration I & II", BOCES Education, Warren Hilliard (instructor), Poughkeepsie, New York, May - July 1982, [classroom notes from air conditioning and refrigeration maintenance and repair course attended by the website author]
• Refrigeration and Air Conditioning Technology, 5th Ed., William C. Whitman, William M. Johnson, John Tomczyk, Cengage Learning, 2005, ISBN 1401837654, 9781401837655 1324 pages
• Carson Dunlop, Associates, Toronto, have provided us with (and we recommend) Carson Dunlop Weldon & Associates' Technical Reference Guide to manufacturer's model and serial number information for heating and cooling equipment ($69.00 U.S.).
• Air Conditioning Inspection, Diagnosis, Repair, Efficiency all the basics for home owners, inspectors, new repairmen
• Air Conditioning SEER - New DOE Air Conditioner and Heat Pump Efficiency Standard
• Asbestos HVAC Ducts and Flues field identification photos and guide
• Fiberglass: Indoor Air Quality Investigations: Fiberglass in Indoor Air, HVAC ducts, and Building Insulation
• Ratib Bakera is member of Refrigeration Service Engineers Society (RSES), an International training organization for the HVACR industry provides educational and certification programs to HVACR professionals of all experience levels. www.rses.org provides information on the organization and its training materials. Independent testing and certification of HVAC technicians is provided by North American Technician Excellence - NATE - see www.natex.org. NATE is supported by ASHRAE, the US EPA, and a host of other trade and professional associations.
• Singer brand HVAC equipment brand history: Singer was bought by & became the climate control unit of Dallas-based Snyder General Corp. (founded by a former Singer HVAC manager) in 1982. The name Singer was dropped in 1984. In 1984 Snyder General operations included Arcoaire, Comfortmaker, and McQuay. In 1991 Snyder General sold Arcoaire & Comfortmaker to Inter-City Products. In 1994 Snyder General was acquired by Hong Leong Group Malaysia. Snyder General is at 2001 Ross Avenue Dallas, TX 75201.
• Lennox air conditioning and heat pump owners manuals for air conditioners, air handlers, furnaces, heat pumps, indoor air quality systems, packaged units, water heaters, zone controls and other controls such as thermostats, are provided by Lennox at http://www.lennox.com/support/manuals.asp
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