InspectAPedia ^®

The limitations of visual inspection of A/C systems are described here. This website answers most questions about air conditioning systems. We describe how to inspect residential air conditioning systems (A/C systems) to inform home buyers, owners, and home inspectors of common cooling system defects.

The chapters a this website describe 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. 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. © Copyright 2009 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use links 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.

3. INSPECTION LIMITATIONS - Air Conditioning System Inspection Limitations

A home inspector is expected to at a minimum, perform a visual inspection of the cooling system and all of its visually accessible components, and to identify significant or dangerous defects. "Inspect" means "operate" or "turn on" if site conditions do not give the inspector a reason not to operate the equipment.

The ASHI, NAHI, CREIA, TAREI, FABI, CAHI, and other professional home inspection associations set inspection standards as do many U.S. states and Canadian provinces which license and regulate home inspectors. Home inspection standards generally do not require that equipment be disassembled, tested with instruments (amp probes, refrigerant gas detectors, coolant pressure measurements). In addition, the inspector is not expected to inspect any equipment, component, system, or area of a building if in the inspectors opinion that action is unsafe or is likely to cause costly damage.

"Non-central" air conditioners such as window units and "through wall" units (which are basically the same portable devices) are excluded from inspection by most standards. We would interpret ductless systems such as those shown at A/C TYPES, ENERGY SOURCES to be equipment that should be included in a home inspection as these are substantive, permanent systems and they operate using controls similar to ducted central air systems.

These limitations apply to home inspectors examining cooling systems and heat pumps, especially if the equipment appears to be in dangerous condition (damaged wiring for example), or is in a "shut down" or "seasonally shut down" condition, such as operating a cooling system during low temperature conditions.

While home inspectors may omit certain items from inspection under appropriate conditions, the inspector is still required to explain that omission to the client and, where appropriate, to offer follow-up advice.

Below are offered example home inspection report wording describing typical limitations on the ability of a home inspector to examine the condition of an air conditioning or heat pump system. [Contributions and critique are invited.]

COOLING SYSTEM INSPECTION LIMITATION: We check for normal temperature differential between input and output air, unusual operating noises, visible damage or defects, and a variety of other possible defects. This inspection is not technically exhaustive; a more thorough inspection, also not technically exhaustive, can be performed by a qualified HVAC service professional, and is recommended when any defects or malfunction are suspected.

Here are some examples of warning language we might use in a report. A system is not considered "not useable" simply because it was shut down, but if it was shut down, not operated, and by visual inspection, has visible major defects, we would go further to explain this condition, even though the system was not turned on. A home inspector who sees that a system is visibly damaged, missing components, or antiquated, but who uses the escape clause of "it was shut down and not inspected" to say nothing more to his/her client, is not doing the best job for the client.

Central Air Shut Down, Not Tested Due to Temperatures

As the cooling equipment had clearly been shut down and because the weather temperature in the past 24 hours has been below 65 degF. we were not able to test-operate this equipment. Operating cooling system equipment which has been "shut down" without proper preparation risks costly damage to the compressor or other components.

Note: some compressor motors can be seriously damaged by being "slugged" with liquid refrigerant or by lack of good lubrication if the compressor is started in cold conditions. Some air conditioner units, including heat pumps, are likely to have a heater band installed around the compressor motor to keep its temperature up to operating state in cold weather. If such a system using a motor heater has been left with power off for some time, simply turning it on in cool weather is not enough as the heater would need time to warm up the motor.

Central Air System Shut Down, Not Tested Due to Condition

• burned electrical wiring at the air conditioning system controls
• open fans, a serious safety hazard
• the building has a large area of visible mold - running the system risks distributing potentially allergenic or harmful particles throughout and also risks contaminating the HVAC system duct work and air handler
• other:___

We recommend that you make no attempt to turn the air conditioning or heat pump system on before having it examined by a qualified air conditioning service person. If replacement of major components is required, repair is likely to involve a significant expense. Inspection and repair are needed before you can use the system.

Share this Article      

...

Technical Reviewers & References

Search InspectAPedia

• Daniel Friedman - principal author/editor of the InspectAPedia^® Website
• 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
AIR CONDITIONER BTU CHART
AIR CONDITIONER COMPONENT PARTS
AIR CONDITIONER TYPES, ENERGY SOURCES
AIR CONDITIONER NOT WORKING
AIR FILTERS for HVAC SYSTEMS
AIR HANDLER UNIT
BACKUP HEAT for HEAT PUMPS
BLOWER DOORS & AIR INFILTRATION
BOOKSTORE - Air Conditioning "How To" Books
CLEANING & Legionella BACTERIA
COMPRESSOR & CONDENSING COIL
CONDENSATE HANDLING
CONTROLS & SWITCHES
COOL OFF HEAT Thermostat Switch
COOLING CAPACITY, RATED
COOLING COIL or EVAPORATOR COIL
DATA TAGS on AIR CONDITIONERS
COMBUSTION GASES & PARTICLE HAZARDS
COMBUSTION PRODUCTS & IAQ
DEFINITION of Heating & Cooling Terms
DEW POINT CALCULATION for WALLS
DEW POINT TABLE - CONDENSATION POINT GUIDE
DUCT SYSTEMS
DUCTS - Asbestos
DUCT SYSTEM DEFECTS
DUCT INSULATION, Asbestos Paper
DUCT INSULATION for SOUNDPROOFING
DUCTS, Asbestos Transite Pipe
DUST FROM HVAC?
ENERGY SAVINGS in BUILDINGS
EVAPORATIVE COOLING SYSTEMS
FAN AUTO ON Thermostat Switch
HEAT LOSS (or GAIN) in BUILDINGS
HUMIDITY LEVEL TARGET
INSPECTION CHECKLIST - OUTDOOR UNIT
INSPECTION LIMITATIONS
LOST COOLING CAPACITY
MOTOR OVERLOAD RESET SWITCH
OPERATING COST
OPERATING DEFECTS
OPERATING TEMPERATURES
REPAIR GUIDE for AIR CONDITIONERS
REPAIR & DIAGNOSTIC FAQs for A/C
REFRIGERANTS
SEER RATINGS & OTHER DEFINITIONS
SYSTEM OPERATION
SWAMP COOLERS
THERMOSTATS
THERMOSTATIC EXPANSION VALVES
CRITICAL DEFECTS on A/C SYSTEMS
FURNACES WARM AIR HEATING SYSTEMS
INDOOR AIR QUALITY IMPROVEMENT GUIDE

• 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.
• 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.
• 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.).
• ...

More Information on Building Diagnostic Inspections and Repairs

• 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

InspectAPedia® Home & Site Map - Building & Environmental Inspection, Testing, Diagnosis, Repair, & Problem Prevention Advice: In-depth research & advice on diagnosing, testing, correcting, & preventing building defects & indoor environmental hazards. Unbiased information, no conflicts of interest.

The Mold Information Center: What to Do About Mold in Buildings, When and How to Inspect for Mold, Clean Up Mold, or Avoid Mold Problems

Use this simple, economical mold test kit by following our instructions on how to collect and mail mold samples to our lab

Environmental Inspection, Testing, & Diagnosis On-Site IAQ, Gas, Air Testing, Mold Investigation, Sick Building Diagnosis, Lab Services, & Remediation Plan Preparation - indoor air quality testing, problem source determination, supporting lab work, written remediation plan addressing removal of environmental and other hazards and prevention of their recurrence.

Building Inspection, Problem Diagnosis, Forensic Investigation & Testing, Repair Consulting

Contact Daniel Friedman for website content suggestions or for fee-paid consulting