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AIR CONDITIONING & HEAT PUMP SYSTEMS

A/C - HEAT PUMP CONTROLS & SWITCHES
A/C DATA TAGS
A/C - HEAT PUMP CRITICAL DEFECTS
A/C DIAGNOSTIC FAQs
A/C REFRIGERANTS
A/C TYPES, ENERGY SOURCE
AGE of AIR CONDITIONERS & HEAT PUMPS

AIR CONDITIONER BTU CHART
AIR CONDITIONER COMPONENT PARTS
AIR CONDITIONER TYPES, ENERGY SOURCES
AIR CONDITIONER NOT WORKING

AIR FILTERS for HVAC SYSTEMS

AIR HANDLER / BLOWER UNITS
APPLIANCE EFFICIENCY RATINGS
BACKUP HEAT for HEAT PUMPS

BLOWER DOORS & AIR INFILTRATION
BLOWER FAN CONTINUOUS OPERATION
BLOWER FAN OPERATION & TESTING

BOOKSTORE - Air Conditioning "How To" Books

CAPACITORS for HARD STARTING MOTORS
CAPILLARY TUBES
CHINESE DRYWALL HAZARDS
CIRCUIT BREAKER SIZE for A/C or HEAT PUMP
CLEANING & Legionella BACTERIA
CHINESE DRYWALL HAZARDS
COMBUSTION GASES & PARTICLE HAZARDS
CONDENSATE HANDLING, A/C
CONDENSATION or SWEATING PIPES, TANKS
COMPRESSOR & CONDENSING COIL, A/C
  BURNED-OUT COMPRESSOR
  CAPACITORS for HARD STARTING MOTORS
  CONDENSING COIL REPAIR REPLACE
  CONTACTOR RELAY DIAGNOSIS & REPAIR
  CONTROL CIRCUIT BOARD, A/C
  FAN, COMPRESSOR/CONDENSER UNIT
  HARD STARTING COMPRESSOR MOTORS
  INSPECTION CHECKLIST - OUTDOOR UNIT
  INSTALLATION ERRORS, COMPRESSORS
  LONG-ON CYCLING AC COMPRESSOR
  MOTOR OVERLOAD RESET SWITCH
  NOISES, COMPRESSOR CONDENSER
  Pressure Controls & Safety Switches
  PRESSURE READINGS, COMPRESSOR
  REPLACING A COMPRESSOR
  SHORT CYCLING AC COMPRESSOR
  TIGHT or SEIZED AC COMPRESSORS

CONDENSATE HANDLING, A/C
CONDENSATION or SWEATING PIPES, TANKS
COOL OFF HEAT Thermostat Switch
COOLING CAPACITY, RATED
COOLING COIL or EVAPORATOR COIL
COOLING LOAD REDUCTION by ROOF VENTS
COMBUSTION GASES & PARTICLE HAZARDS
CONDENSATE HANDLING, A/C
CONDENSATION or SWEATING PIPES, TANKS

DATA TAGS on AIR CONDITIONERS
DEFINITION of Heating & Cooling Terms

DEHUMIDIFICATION PROBLEMS
DEW POINT CALCULATION for WALLS
DEW POINT TABLE - CONDENSATION POINT GUIDE

DIAGNOSE & FIX AIR CONDITIONER / HEAT PUMP
DUCT SYSTEM & DUCT DEFECTS
DUCTS - Asbestos
DUCT INSULATION, Asbestos Paper
DUCT INSULATION for SOUNDPROOFING
DUCT SYSTEM NOISES
DUCTS, Asbestos Transite Pipe
DUST CONTAMINATION FROM HVAC?

EDUCATION, HVAC SCHOOLS
ELECTRIC MOTOR DIAGNOSTIC GUIDE
ELECTRIC MOTOR OVERLOAD RESET SWITCH
ELECTRICAL POWER SWITCH FOR HEAT

ENERGY SAVINGS in buildings
EVAPORATIVE COOLING SYSTEMS
EVAPORATOR COIL or COOLING COIL
EXPANSION VALVES, REFRIGERANT

FAN, AIR HANDLER BLOWER UNIT
FAN AUTO ON Thermostat Switch
FAN, COMPRESSOR/CONDENSER UNIT
FAN CONVECTOR HEATERS - HYDRONIC COILS
FAN LIMIT SWITCH
FAN NOISES

FURNACES WARM AIR HEATING SYSTEMS

GASES, EXPOSURE, TESTING
  Carbon Dioxide - CO₂
  Carbon Monoxide - CO
  METHANE GAS SOURCES
GAS MEASUREMENT TOOLS
GAUGE, REFRIGERATION PRESSURE TEST

HEAT LOSS (or GAIN) in buildings
HEAT PUMPS

HUMIDITY LEVEL TARGET

INDOOR AIR QUALITY IMPROVEMENT GUIDE
INSPECTION LIMITATIONS
INSPECTION CHECKLIST - OUTDOOR UNIT
LOST COOLING CAPACITY

MANUALS & PARTS GUIDES - HVAC
MOTOR OVERLOAD RESET SWITCH

NOISY AIR CONDITIONER / HEAT PUMP
NOISE / SOUND DIAGNOSIS & CURE
  Air Leak Noises
  AIR CONDITIONING & HEAT PUMP NOISES

OPERATING COST
OPERATING DEFECTS
OPERATING TEMPERATURES

PORTABLE ROOM AIR CONDITIONERS
PRESSURE READINGS, REFRIGERANT

REPAIR GUIDE, AIR CONDITIONERS / HEAT PUMPS
REPAIR & DIAGNOSTIC FAQs for A/C

REFRIGERANTS
  GAUGE, REFRIGERATION PRESSURE TEST
  REFRIGERANT CHARGING PROCEDURE
  REFRIGERANT DRIERS & FILTERS
  REFRIGERANT LEAK DETECTION
  REFRIGERANT LEAK REPAIR
  REFRIGERANT METERING DEVICES TEVs
  REFRIGERANT METERING CAPILLARY TUBES
  REFRIGERANT PIPING & DISTANCES
  REFRIGERANT PRESSURE READINGS
RETROFIT SIZING for A/C or HEAT PUMPS

SEER RATINGS & OTHER DEFINITIONS
SOLAR ENERGY SYSTEMS
SPLIT SYSTEM AIR CONDITIONERS & HEAT PUMPS
SWAMP COOLERS
SYSTEM OPERATION

THERMOSTATS, HEATING / COOLING
THERMOSTATIC EXPANSION VALVES

WATER COOLED AIR CONDITIONERS

More Information

Photograph of air conditioning compressor condenser units with many problems

Air Conditioner Compressor & Condenser Installation Errors
InspectAPedia^® -

Air conditioner compressor installation errors
Air conditioner compressor defect diagnosis
Air conditioning refrigerant line defects
Air conditioning refrigerant piping distances and diameters required
Allowable distances between air conditioning compressor and air handler
Questions & answers about installing air conditioners and heat pumps

This air conditioning repair article discusses the installation errors in air conditioning compressor and condensing units.

InspectAPedia offers impartial, unbiased advice without conflicts of interest. We will block advertisements which we discover or readers inform us are associated with bad business practices, false-advertising, or junk science. Our contact info is at InspectAPedia.com/Contact.htm.

Maintenance tips including attention to compressor support pads and avoiding air conditioning refrigerant leaks are addressed. If readers return to the first chapter or view the A/C chapter index, the major components of an air conditioning system are described, sketches and photographs are provided, and common defects for each component are listed along with visual or other clues that may suggest a problem or probable failure of A/C components.

We explain how an air conditioning service technician will diagnose certain common air conditioning system failures or defects. If your air conditioning or heat pump system has lost its cooling capacity or won't start see REPAIR GUIDE for AIR CONDITIONERS. see How to determine the cooling capacity of air conditioning equipment if the system seems to be working but is inadequate to cool your building.

Contact us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution.

© 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.

INSTALLATION ERRORS - Air Conditioning Compressor Installation Errors & Damage

Air Conditioning Compressor Location Problems

Inadequate air circulation clearance around an air conditioner compressor/condenser unit

Photograph of a tipping air conditioning compressor

Typical outside air-cooled A/C compressors require a minimal clearance around the unit to provide adequate air flow so that the condenser coils will be cooled efficiently. Both of the air conditioning installations shown here are tipping and the right hand one was actually leaning on the house wall!

Air conditioning compressor/condenser units mounted too close to a wall, surrounded by shrubs, or multiple units located too closely together may not receive enough cool air flow to function properly. The result can be a shorter compressor life (expensive) and/or less efficient cooling operation (higher operation costs).

These four air conditioner compressors were found jammed into a wall niche along a street in Queretero, Mexico. These units may have a short life before needing replacement.

Where there simply is not adequate space to provide proper air circulation around an air conditioning compressor or multiple compressors, it may be a good idea to let the building owner know that the units won't have a long life.

Tipped or leaning air conditioner compressor/condenser units

Tipping or leaning air conditioner compressors can lead to so much movement that the refrigerant lines crack and leak, leading to loss of cooling ability. In extreme cases, a tipped condenser unit may fail to operate properly. In the first photo above the compressor is leaning and creeping away from the building and has pulled its connecting wiring and refrigerant line taut.

I expect a problem soon with this unit. In the second photo everything looks awful: the two compressors are too close together and too close to the building wall for adequate air circulation, especially in the larger rear unit in the photo. The safety electrical switch for the air conditioner is falling off of the wall, and the rear unit is sliding off of its support pad. This was a poor air conditioning system installation.

Air Conditioner Compressor/Condenser Units Overgrown with Shrubbery

This collection of air conditioning compressors are too many too close together - they will be fighting for cooling air around the condenser unit, increasing operating cost and shortening air conditioner compressor life.

Adding to this scene is the overgrowth of shrubs along the compressor/condenser units. The owner didn't want to see these "ugly" devices but she should have kept the plants trimmed off of the units themselves to allow airflow. The shade was a great idea however, so long as these are just air conditioning units and not heat pumps that want warmth in winter.

One of our clients was "punished" by their air conditioner installer when she said that she didn't want to see or hear the compressor/condenser units, and when she was installing nine of them at her large home. The installer built a rack allowing the units to be stacked on top of one another, three across and three high, with very little air space between.

Then the installer put up a stockade fence just a few inches away from the compressor/condenser units. They were hard to see, it was true, and hard to service. But as the property manager confirmed, they were having to replace several of these units every few years. I believe it was because the units ran excessively hot all the time, lacking adequate air and clearance. Photo withheld for privacy.

Air Conditioner Refrigerant Line Defects

Please see our detailed article about refrigerant line piping installation, inspection, defects, repairs, found at REFRIGERANT PIPING & DISTANCES. Excerpts below:

Refrigerant Line Mounting Requirements

Absence of slack in the coolant lines at the compressor units can cause leaks: should the compressor move, perhaps because its supporting pads settle, there will be likely leaks at these lines. You should review this question with your HVAC service person. This item may be deferred until next maintenance or service.

Protection from mechanical damage on all refrigerant lines is important to prevent leaks.

Also, referring lines should not be buried underground. Details are at REFRIGERANT PIPING & DISTANCES.

Refrigerant Line Insulation Requirements

Missing insulation on the refrigerant lines, particularly on the larger suction line, will cause condensation and drips from the lines in humid areas. I've seen very costly building damage where lines were not properly insulated indoors: condensate drips wet gypsum board walls, leading to a costly mold remediation project. Missing insulation also probably increases system operating cost. Details are at REFRIGERANT PIPING & DISTANCES.

Air Conditioning Equipment Distances

Moving an air conditioner compressor to a distance of about 40 feet from a building won't prevent it from working, but the installer might need to adjust the diameter of the refrigerant lines to be sure that the equipment is working at 100% of its capacity.

it's not that the air conditioner won't work at all if the compressor/condenser is located at an unusual distance from the air handler/evaporator coil, it's more that it may lose some capacity and have to work harder - meaning higher electrical bills and in extreme cases, shorter equipment life.

Some air conditioner manufacturers such as McQuay provide a refrigeration piping guide that gives complete, detailed guidance and charts on refrigerant line sizing (diameter) as a function of length of run.

Details about refrigerant piping diameters, distances, and effects on equipment operation are at REFRIGERANT PIPING & DISTANCES.

Questions & Answers regarding this article

Questions & answers about installing air conditioners and heat pumps

Question: Is it OK for the A/C compressor to be out of level?

could a compressor being unlevel cause any issues - DLMC

Reply: Yes. See the manufacturer's level specifications, as we describe below.

Dlmc: - requirement to level the air conditioning or heat pump compressor -

Yes the compressor should be level. That detail is found in the installation instructions for air conditioning and heat pump compressors.

Slightly out of level is unlikely to affect operation, but if you consider that the condenser coil expects to receive high temperature, high pressure refrigerant gas that it then cools to a liquid refrigerant, and that the liquid refrigerant needs to flow out of the condensing coil into the refrigerant line, a significant tip out of level may interfere with refrigerant flow and thus system operation.

Also a unit that is out of level and also not secured to a mounting pad may creep due to equipment vibration, risking development of a leak in the refrigerant lines or a torn electrical connection.

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AIR CONDITIONING & HEAT PUMP SYSTEMS

A/C - HEAT PUMP CONTROLS & SWITCHES
A/C DATA TAGS
A/C - HEAT PUMP CRITICAL DEFECTS
A/C DIAGNOSTIC FAQs
A/C REFRIGERANTS
A/C TYPES, ENERGY SOURCE
AGE of AIR CONDITIONERS & HEAT PUMPS

AIR CONDITIONER BTU CHART
AIR CONDITIONER COMPONENT PARTS
AIR CONDITIONER TYPES, ENERGY SOURCES
AIR CONDITIONER NOT WORKING

AIR FILTERS for HVAC SYSTEMS

AIR HANDLER / BLOWER UNITS
APPLIANCE EFFICIENCY RATINGS
BACKUP HEAT for HEAT PUMPS

BLOWER DOORS & AIR INFILTRATION
BLOWER FAN CONTINUOUS OPERATION
BLOWER FAN OPERATION & TESTING

BOOKSTORE - Air Conditioning "How To" Books

CAPACITORS for HARD STARTING MOTORS
CAPILLARY TUBES
CHINESE DRYWALL HAZARDS
CIRCUIT BREAKER SIZE for A/C or HEAT PUMP
CLEANING & Legionella BACTERIA
CHINESE DRYWALL HAZARDS
COMBUSTION GASES & PARTICLE HAZARDS
CONDENSATE HANDLING, A/C
CONDENSATION or SWEATING PIPES, TANKS
COMPRESSOR & CONDENSING COIL, A/C
  BURNED-OUT COMPRESSOR
  CAPACITORS for HARD STARTING MOTORS
  CONDENSING COIL REPAIR REPLACE
  CONTACTOR RELAY DIAGNOSIS & REPAIR
  CONTROL CIRCUIT BOARD, A/C
  FAN, COMPRESSOR/CONDENSER UNIT
  HARD STARTING COMPRESSOR MOTORS
  INSPECTION CHECKLIST - OUTDOOR UNIT
  INSTALLATION ERRORS, COMPRESSORS
  LONG-ON CYCLING AC COMPRESSOR
  MOTOR OVERLOAD RESET SWITCH
  NOISES, COMPRESSOR CONDENSER
  Pressure Controls & Safety Switches
  PRESSURE READINGS, COMPRESSOR
  REPLACING A COMPRESSOR
  SHORT CYCLING AC COMPRESSOR
  TIGHT or SEIZED AC COMPRESSORS

CONDENSATE HANDLING, A/C
CONDENSATION or SWEATING PIPES, TANKS
COOL OFF HEAT Thermostat Switch
COOLING CAPACITY, RATED
COOLING COIL or EVAPORATOR COIL
COOLING LOAD REDUCTION by ROOF VENTS
COMBUSTION GASES & PARTICLE HAZARDS
CONDENSATE HANDLING, A/C
CONDENSATION or SWEATING PIPES, TANKS

DATA TAGS on AIR CONDITIONERS
DEFINITION of Heating & Cooling Terms

DEHUMIDIFICATION PROBLEMS
DEW POINT CALCULATION for WALLS
DEW POINT TABLE - CONDENSATION POINT GUIDE

DIAGNOSE & FIX AIR CONDITIONER / HEAT PUMP
DUCT SYSTEM & DUCT DEFECTS
DUCTS - Asbestos
DUCT INSULATION, Asbestos Paper
DUCT INSULATION for SOUNDPROOFING
DUCT SYSTEM NOISES
DUCTS, Asbestos Transite Pipe
DUST CONTAMINATION FROM HVAC?

EDUCATION, HVAC SCHOOLS
ELECTRIC MOTOR DIAGNOSTIC GUIDE
ELECTRIC MOTOR OVERLOAD RESET SWITCH
ELECTRICAL POWER SWITCH FOR HEAT

ENERGY SAVINGS in buildings
EVAPORATIVE COOLING SYSTEMS
EVAPORATOR COIL or COOLING COIL
EXPANSION VALVES, REFRIGERANT

FAN, AIR HANDLER BLOWER UNIT
FAN AUTO ON Thermostat Switch
FAN, COMPRESSOR/CONDENSER UNIT
FAN CONVECTOR HEATERS - HYDRONIC COILS
FAN LIMIT SWITCH
FAN NOISES

FURNACES WARM AIR HEATING SYSTEMS

GASES, EXPOSURE, TESTING
  Carbon Dioxide - CO₂
  Carbon Monoxide - CO
  METHANE GAS SOURCES
GAS MEASUREMENT TOOLS
GAUGE, REFRIGERATION PRESSURE TEST

HEAT LOSS (or GAIN) in buildings
HEAT PUMPS

HUMIDITY LEVEL TARGET

INDOOR AIR QUALITY IMPROVEMENT GUIDE
INSPECTION LIMITATIONS
LEED GREEN BUILDING CERTIFICATION

LOST COOLING CAPACITY

MANUALS & PARTS GUIDES - HVAC
MOTOR OVERLOAD RESET SWITCH

NOISY AIR CONDITIONER / HEAT PUMP
NOISE / SOUND DIAGNOSIS & CURE
  Air Leak Noises
  AIR CONDITIONING & HEAT PUMP NOISES

OPERATING COST
OPERATING DEFECTS
OPERATING TEMPERATURES

PORTABLE ROOM AIR CONDITIONERS
PRESSURE READINGS, REFRIGERANT

REPAIR GUIDE, AIR CONDITIONERS / HEAT PUMPS
REPAIR & DIAGNOSTIC FAQs for A/C

REFRIGERANTS
  GAUGE, REFRIGERATION PRESSURE TEST
  REFRIGERANT CHARGING PROCEDURE
  REFRIGERANT DRIERS & FILTERS
  REFRIGERANT LEAK DETECTION
  REFRIGERANT LEAK REPAIR
  REFRIGERANT METERING DEVICES TEVs
  REFRIGERANT METERING CAPILLARY TUBES
  REFRIGERANT PIPING & DISTANCES
  REFRIGERANT PRESSURE READINGS
RETROFIT SIZING for A/C or HEAT PUMPS

SEER RATINGS & OTHER DEFINITIONS
SOLAR ENERGY SYSTEMS
SPLIT SYSTEM AIR CONDITIONERS & HEAT PUMPS
SWAMP COOLERS
SYSTEM OPERATION

THERMOSTATS, HEATING / COOLING
THERMOSTATIC EXPANSION VALVES

WATER COOLED AIR CONDITIONERS

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.
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.
Thanks to Scott at SJM Inspect for suggesting the EPA air conditioning and IAQ 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 Diaz, Domingo I. CIV NAVAIR Bldg.2118, rm. 131: domingo.diaz@navy.mil - Ming Diaz, Great Falls, MD for editing help with the text about discharging air conditioning compressor capacitors - 3/07 DF]
Thanks to reader (Anon) for discussing the allowable distance between air conditioner compressor and a building or from the air handler - July 2010
ASHRAE Handbook Refrigeration, Chapter 2, 2006. © American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., www.ashrae.org
Refrigerant Piping Design Guide, McQuay Corporation, Americans HQ: 13600 Industrial Park Blvd., Minneapolis, Minnesota 55441, 800-432-1342 (Toll Free) 763-553-5330 (Direct), 763-553-5177 (Fax). Web search 07/15/2010 original source: http://www.mcquay.com/mcquaybiz/literature/lit_systems/AppGuide/AG_31-011_120407.pdf - quoting:
McQuay International delivers engineered, flexible solutions for commercial, industrial and institutional HVAC requirements with reliable products, knowledgeable applications expertise and responsive support. As part of Daikin Industries, a Fortune 1000 company, McQuay is the second largest air conditioning, heating, ventilating and refrigeration company in the world.

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.

The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 2010, $69.00 U.S., is available from Carson Dunlop. The Home Reference Book is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. InspectAPedia.com ^® author/editor Daniel Friedman is a contributing author. Field inspection worksheets are included at the back of the volume.

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