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The limitations of visual inspection of A/C systems are described here.
This article series 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.
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.
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
The cooling system was shut off at the time of our inspection. By visual inspection we
observed these conditions which suggest that the system should not be turned on
before it is inspected and if necessary, repaired by an HVAC technician:
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
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.
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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
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
"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]
Fiberglass: Indoor Air Quality Investigations: Fiberglass in Indoor Air, HVAC ducts, and Building Insulation
Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: firstname.lastname@example.org. The firm provides professional home inspection services & home inspection education & publications. Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides extensive home inspection education and report writing material.
The Illustrated Home illustrates construction details and building components, a reference for owners & inspectors. Special Offer: For a 5% discount on any number of copies of the Illustrated Home purchased as a single order Enter INSPECTAILL in the order payment page "Promo/Redemption" space.
TECHNICAL REFERENCE GUIDE to manufacturer's model and serial number information for heating and cooling equipment, useful for determining the age of heating boilers, furnaces, water heaters is provided by Carson Dunlop, Associates, Toronto - Carson Dunlop Weldon & Associates Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on any number of copies of the Technical Reference Guide purchased as a single order. Just enter INSPECTATRG in the order payment page "Promo/Redemption" space.
The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, 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. Field inspection worksheets are included at the back of the volume.
Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on these courses: Enter INSPECTAHITP in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
The Horizon Software System manages business operations,scheduling, & inspection report writing using Carson Dunlop's knowledge base & color images. The Horizon system runs on always-available cloud-based software for office computers, laptops, tablets, iPad, Android, & other smartphones