Air Conditioning Inspection Checklist for Owners & Inspectors InspectAPedia® -
A quick visual inspection checklist for the outdoor air conditioning system compressor/condenser unit
How to inspect the outdoor components of an air conditioning system - simple tips for home owners and home inspectors
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This article discusses the how to perform a simple visual inspection of an air conditioning compressor-condenser unit, including
links to more detailed air conditioning inspection,diagnosis and repair articles useful in the evaluation of air conditioner compressor noises, hard starting, lost cooling capacity, and detection of a burned out compressor or A/C compressors at or near end of their life. Maintenance tips including attention to compressor support
pads and avoiding air conditioning refrigerant leaks are addressed. Initial, simple diagnostic checks of the air conditioning compressor are also described at Compressor failure diagnosis.
AIR CONDITIONING SYSTEMS describes the major components of an air conditioning system. Sketches and photographs are provided, and common defects for each A/C component are listed along with visual or other clues that may suggest a problem or probable failure of each components. We explain how an air conditioning service technician will diagnose
certain common air conditioning system failures or defects. We include photographs to assist readers in recognizing cooling system defects.
How do We Inspect an Air Conditioning Compressor - Visual Only
The (usually) outdoor half of a typical air conditioning system is a unit containing the refrigerant compressor and condensing coil.
The air conditioning compressor motor is a pump which draws heat laden refrigerant gas from the building's indoor components (evaporator coil and air handler), and compresses the low pressure refrigerant gas to high pressure and higher temperature.
The diagnosis and repair of various defects in the air conditioning compressor/condenser unit are discussed in detail using the links
provided at the left of this page.
Here is a little visual inspection checklist that any homeowner or home inspector can perform.
Minimum Air Conditioner Compressor Unit Inspection Checklist for an Air Conditioner Report - Outdoor Unit Observations
Location of the Compressor/Condenser: Locate the outdoor unit or units and look at the characteristics of just where the unit(s) have been placed:
Is there good air circulation around the compressor/condenser unit or is it too close to a wall, to close to an overhead deck, porch, shrubs - Details are at INSTALLATION ERRORS, COMPRESSORS
Is the unit too close to the property line - a possible noise issue for neighbors or a local building code violation? Most municipalities require that the compressor be at least 10' from the property line.
Is the compressor/condenser too close to a gas appliance vent or to a clothes dryer vent? - Details are at INSTALLATION ERRORS, COMPRESSORS
Are all of the cabinet parts and cabinet base above ground - the unit should not be partially buried
Condition of the compressor/condenser cabinet: look for rust damage or dents from having been struck by a garden tractor or dropped during installation
Condition of the compressor/condenser condensing coil: look for evidence of damage to the cooling fins or dirt, debris, grass clippings blocking the air flow of the unit. See CONDENSING COIL FINS, SUPPORT PADS
Condition of the compressor/condenser fan: look for evidence of damage to the fan itself (rare)
Presence of an electrical service disconnect switch at the air conditioner compressor/condenser: a service disconnect switch, fuse, or circuit breaker should be installed, usually on the building wall close to the unit. Check the size of the fuse or circuit breakers and compare with the overcurrent protection specified on the data plate on the compressor/condenser unit body. See CONTROLS & SWITCHES.
Condition of the wiring to the air conditioner compressor/condenser unit: look for signs of damage or overheating, broken conduit that should be protecting the wiring. A home inspector or electrical inspector will compare the size (current carrying capacity) of the wiring with the fuse or circuit breaker size and the size specified by the data tag. She should also check that the wiring to the compressor/condenser is rated for outdoor use or is suitably installed in conduit. See ELECTRICAL INSPECTION, DIAGNOSIS, REPAIR.
Condition of the air conditioner refrigerant lines: look for lost insulation on the suction line; look for absence of any bend or slack in the refrigerant line; if the compressor/condenser is connected to copper piping that is rigid between the unit and the building wall, vibration, settlement, slight movement can produce a refrigerant leak. See REFRIGERANT LEAK DETECTION.
Air Conditioner Data Plate Information: is there a data plate at all? If you can find it, record the model, serial number, and other data from this tag - it can help locate service manuals, system specifications such as RLA, maximum fuse size, and it will permit you to find the age and cooling capacity of the unit. See DATA TAGS on AIR CONDITIONERS. A home inspector can be asked to make a rough comparison between the cooling capacity of the compressor and the square footage of the building it serves. See COOLING CAPACITY, RATED for how to do this, and see AIR CONDITIONER BTU CHART.
If the compressor can be run, listen to the motor and fan motor when the unit starts and after it gets running; Noisy or hard starting compressors may be at or near the end of life or may need service and repair. See NOISY COMPRESSOR UNITS, and see OPERATING DEFECTS.
Operating temperatures: a home inspector or service technician may use other instruments, including measuring simple air temperatures at the compressor/condenser to get an idea how well the system is functioning. See OPERATING TEMPERATURES.
Air Conditioning System Diagnostic Articles
At LOST COOLING CAPACITY, our focus is on the case in which the air conditioning system seems to be "running" but not enough cool air, or no cool air at all is being delivered to the occupied space. Sketch from Carson Dunlop.
At OPERATING DEFECTS we take you through the major air conditioning problem symptoms and how to get the air conditioning system working again.
At CONTROLS & SWITCHES we explain the many electrical switches and controls that control an air conditioner or heat pump system. You'll need to check these if your air conditioner won't start.
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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.
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 Alan Carson and Bob Dunlop, Carson Dunlop, Associates, Toronto, for permission to use illustrations from their publication, The Illustrated Home which illustrates construction details and building components. Carson Dunlop provides home inspection education, publications, report writing materials, 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.).
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
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Our recommended books about building design, inspection, and repair, and about indoor environment testing, diagnosis, and cleanup are at the InspectAPedia Bookstore.
"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]
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.).
More Information on Building Diagnostic Inspections and Repairs
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