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How to inspect and diagnose heating system condition: This heating system inspection article and other articles at this website explain Heating System Inspection Concepts - how to prepare for and control the heating system inspection process to assure that
the inspection is complete and accurate. We describe how to inspect, troubleshoot and repair heating and air conditioning systems to inform home owners, buyers, and home inspectors of common heating system defects.
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How to Inspect Heating Systems - Example of An Approach to the Forensic Inspection of Any Complex System
This document presents a detailed methodology for inspecting, diagnosing, & repairing defects on residential heating systems
with attention to inspection methods selected to assure completeness, accuracy, and the maximum level of defect detection.
The heating system inspection methodology described here serves as a guide to the forensic diagnostic inspection of any complex system where the highest probability of detecting
important safety or operating defects is important.
We describe organized procedures for inspecting complex systems for defects, without losing the ability to discover unexpected problems as well.
How to Relate Heating System Inspection Procedures to Home Inspection Standards of Practice
This presentation follows a procedure for inspecting, using heating system operating sequence as a method to assure that all important
system components are considered. A version of the ASHI Standards of Home Inspection Practice (readers should check most
recent Standards version for changes) is mapped into this heating system inspection procedure but does
not guide the actual inspection sequence. The organization of home inspection standards is not intended as a guide to an
inspection sequence nor as a guide to heating system inspection reports.
Home Inspection Standards requirements during the inspection of a home heating system are identified in italics in the text below.
HEATING INSPECTION CONCEPTS - How to Select an Inspection Methodology for Heating System Inspection & Diagnosis
Step 1: Select a Heating System Inspection Road Map to Guide the Inspection Sequence
In order to be as thorough, accurate, and safe as possible, a heating system inspector should use a well-defined order of discovery
which assures that s/he examines all important heating system components. Several possible heating system inspection "road maps" can be used
for this purpose. Two approaches inspect the heating equipment by physical layout of components,
or by inspecting the heating system in the detailed order that it will operate during
the heating system operating cycle.
Of these "heating system inspection road maps", the first of these inspection methods is physically convenient, that is:
inspect each heating system component where each is located in each building area, and this is the most common approach in use
in the field.
But but it is the second option, heating boiler or furnace operating sequence, that best
assures that the inspector considers proper system operation and that s/he identifies all of the system components.
Thinking thorough the sequence of steps in operation of a home heating system requires that the inspector understand how heating systems work. An inspector who cannot follow this sequence does
not understand heating system operation and is rather likely to miss important system defects.
So how should a heating system be inspected? For efficiency the inspector may decide to examine each system component as s/he enters the
area of the building where that component resides. So all heater components in the basement or crawl space are examined in one pass while
the inspector is in that area, and so on.
But in thinking about the completeness and accuracy of the heating system check the inspector
should also think through the system's operating sequence, using the components identified in that sequence to assure that s/he has not
omitted something important. Why is this second thought pattern needed? Because it is always easier to inspect and think about a building
component that we see than to think about a component that is simply absent. In other words, if there is no temperature or pressure relief
valve to see on a boiler, the inspector may fail to think about whether or not this is a serious safety hazard for the
How to Inspect a Heating System using Physical Location of Components
This approach broadens the scope of the heating system inspection and it
may aid in heating system defect recognition or problem diagnosis, for example by observing that a heating boiler is located in a small, air-tight room (possible
combustion air problems), or that the furnace is quite close to the oil storage tank.
Identify the heating system components in each building area.
At the heating boiler or furnace, identify the fuel source and follow fuel supply piping to its source (an oil tank, LP gas tank, or
gas meter, for example).
At the boiler or furnace, identify the heat distribution method and follow the delivery of heat (warm air or hot water) leaving the
furnace or boiler, and returning to it. Failure to consider this whole path logically risks failing to notice potential problems such as
return air taken at a furnace itself or the absence of adequate return air.
At the boiler or furnace identify each of the controls and safety devices and observe their condition. Those devices that are intended
for normal operation by the home owner are usually also operated and tested by the inspector. Other devices such as temperature/pressure
relief valves are not normally operated but are visually inspected for evidence of a problem.
How to Inspect a Heating System Using the Sequence of Heating System Operation
This approach to heating system inspection
Identifies most components of heating systems or of other mechanical systems and is most likely to give the most complete list system
parts. It helps assure that all critical components are considered. Actual observation of heating system
operation is important in enabling the inspector to identify malfunctions.
The heating boiler or furnace inspector's field procedure should include this aid.
The Importance of Reporting to the Client the Significance of Heating System Defects
A superficial heating system inspection may simply identify the type of system present and perhaps the presence
of obvious visual anomalies such as leaks. But an astute inspector understands more thoroughly the implications
for safety or function of the defects that s/he observes and thus is more likely to inspect the heating system
more thoroughly and is more likely to report the inspection findings in a meaningful way to the client.
It is essential that a heating system inspector clearly communicate to the client the significance of
the inspection results. In other words, the client should be given to understand the need for action, or urgent
action, the presence of unsafe conditions, or the indications that costly repairs or replacement are likely to be
needed immediately or in the coming year or before next heating season.
The Importance of Thinking about the Possible Significance of Home Inspection Observations
Here are two examples of the difference between simply reporting a home inspection observation
neutrally and thinking about the significance of a home inspection observation in a way that might lead to discovery of something important about a heating system.
Example Outdoor Inspection Observation: drip lines below roof eaves
Observation: The heating system inspector, before entering the home, observes outside that there are
deep drip lines in the soil below the home's roof eaves. Drip lines indicate that there has been long term poor control of roof runoff.
Interpretation: there may have been a history of wet basement conditions.
Implications: especially if the home is heated by a furnace located in the basement or crawl space,
watch out for signs of rusting of the furnace heat exchanger, particularly in steel hot-air furnaces. A rusted
and thus leaky furnace heat exchanger is a possibly dangerous condition, risking high Carbon Monoxide CO levels in the building - a condition
that can lead to a fatality - someone could die.
Action: look inside for corroborating clues first of water entry and second of
rust on the furnace or its components. Test or recommend testing of heat exchanger for leaks and safety.
An Example of Neutral (irresponsible) home inspection reporting of heating system condition:
Outside we observed roof overflow or drip lines below the house eaves.
Inside, A BrandX natural-gas fired 90,000 BTUH steel hot air furnace heating system is installed. The system appears to be 20 years old.
In response to turning up the heat we observed that the
system operated normally: heat came out of the air supply registers. (Our inspection excludes heating
system disassembly and therefore cannot examine the condition of the furnace interior components. You should
have the system inspected by a qualified technician.
An Example of More-responsible home inspection reporting of heating system condition:
Outside we observed roof overflow or drip lines below the house eaves. This means that water has been spilling by the
house foundation for a long time, that roof gutters and downspouts are needed, and that the home may have been exposed to
a history of water entry or leaks which in turn could cause problems indoors.
Inside, A BrandX natural-gas fired 90,000 BTUH steel hot air furnace heating system is installed.
The system appears to be 20 years old and based on age alone is likely to be at or near the end of its useful life - significant
expense will be involved when furnace replacement is needed.
In response to turning up the heat we observed that the
system operated normally: heat came out of the air supply registers. Our inspection excludes heating
system disassembly and therefore cannot examine the condition of the furnace interior components.
However, we observed heavy rust on the bottom of the furnace and other evidence of a history of water entry
in the basement. A furnace exposed to these conditions is at extra risk of hidden rust damage such
which could include a leaky heat exchanger. If the heat exchanger is leaking this heating
system would be unsafe, should not be used, and would almost certainly require immediate replacement -
a significant expense.
We recommend that before completing purchase of the home, and certainly before using the system in the
coming heating system, you should have the furnace inspected and tested by a qualified technician, and you should
specifically ask the technician to make a thorough inspection and test of the furnace heat exchanger for leaks
For effective examination of any complex structure, the professional uses all of these tools
Addressing the question of completeness of coverage of components,
for a thought-guide to inspecting heating equipment we selected Sequence
of Operation as a model.
It is the possible significance of a home inspection observation that leads a good inspector to examine the property further for confirmation or refutation of the presence of
a possibly serious building defect. We discuss this concept of thinking carefully about and pursuing possible implications of home inspection
observations as a way to assure that an inspection is thorough and as a means to minimize the chances of missing an important condition at a property, in these articles:
Step 2: Select a Heating System Inspection Viewpoint to Maximize Defect Detection
Broad or distant inspection viewpoint: example: is the building in a flood plain?
Close or detailed heating system viewpoint: example: is there severe rust inside the furnace return air plenum base?
Combined broad and detailed views increase the chances of finding important heating system defects
When inspecting heating systems, while a dramatic and obvious visual clue such as severe rust on a furnace may catch our attention (beware of attention capture errors which make you miss something else), we usually start with broad views, examine further with detailed views, and again make final checks with a broad view.
For home inspections in general because many building systems and conditions affect one another (no gutters, wet basement, rusted furnace, dangerous conditions), a broad view is appropriate for most topics, even where a detailed examination is always made.
Step 3: Observe, Record, & Report Actual or Probable Heating System Defects
Apply a well-defined methodology using
Distant heating system views
Detailed heating system views
Final distant views
What sort of defects should you look for when inspecting a heating system?
Improper Heating System Construction/Installation
Improper Heating System function
Heating System Damage
Missing Heating System Components
Clues of potential heating system defects
What do your heating system inspection observations actually mean?
Report the basic identification data required by home inspection practice
Report unsafe conditions
Report evidence of system malfunction or visually obvious inadequacy (e.g. no return air to a furnace)
Report conditions likely to require significant cost to repair or replace
Think about remote impacts on other systems
Examples of Small Heating System Clues with Big Heating System Implications
Leaky oil at an oil burner ignition transformer: watch for back pressure in combustion chamber--watch out for blocked heating flue or blocked chimney - these would be unsafe, or the heater may be unreliable. An unreliable heater can lead t
frozen burst pipes and costly building damage. A blocked chimney could lead to a potentially fatal carbon monoxide hazard.
Unusual interior moisture conditions, noises, smoke, or odors during heating season--watch for blocked chimney or poor flue vent connections
Equipment recalls: Specific heating system problem brands Repco, Blueray etc.
[Do not confuse Repco™ heating boilers, which had fire chamber and other failures, with other products (REPCO pumps, REPCO controls, REPCO water conditioners, or water treatment that carry the Repco name. Those products are distinct from REPCO heating boilers and are produced/distributed by the R.E. Prescott Company. Further, we are unaware of any remaining warranty or replacement support for failed or antiquated Repco heating boilers.]
BLUE vs YELLOW COMBUSTION FLAMES - the Blueray history and blue flame vs. yellow flame combustion, flame color & combustion efficiency, & how oil competes with gas as a heating fuel.
PREPARATION - How to Prepare in Order to Assure a Thorough Heating System Inspection
Here we explain how to prepare for and control the inspection process.
When inspecting any building or building component the inspector should
generally proceed in this simple order: Look, Think, Understand/Speculate-wait, Write, Speak. We've found that if
we start talking too soon we often have to change our mind about the importance of what we've seen as further
inspection and new clues produce more data. We've found that if we start talking before we've written down
our observations, there is a real risk that our final notes and report may be incomplete and may not coincide
perfectly with what we said to the client during the inspection. Any substantive differences in observations
or conclusions between the onsite oral report and the written inspection report are an invitation to misunderstanding
Before the Heating Inspection
Prior education & experience of the inspector: a good heating system inspector prepares
by knowledge (education and experience) and attitude (for whom ins the inspector working and how diligent is
the inspector going to be?). An inspector who schedules many inspections in a given day is unlikely to have
the time nor the ability to attend to those details that make for a competent and responsible job.
At the Office - when the inspection order is taken Obtain Advance Information
Age of house--how old might the heating (and other) equipment be?
Location (neighborhood)--is it a builder's development with all boilers of a particular problem-brand?
Price range--is it a higher priced house likely to have more costly equipment or multiple heating systems?
Type of house--large "H" ranch (one story) may have two separate furnaces
Buyer's concerns--comments about heating system volunteered by client?
Is the home occupied? Has the heating system been winterized or has it been left on and operating?
If home has not been winterized, has the seller agreed to have the equipment turned on and working or has s/he given permission to the inspector to turn on the system?
Was work on the heating system performed by the seller or by amateurs? IE: "the owner converted the basement" [and did heating and electrical work?]
Driving to the inspection
The inspector should be rested, healthy, attentive, and with his/her mind on work
If not, the inspector must recognize that extra effort will be needed to tune attention to the task about to begin.
Do not perform an inspection if the inspector are seriously ill or distracted. Life-safety issues may be missed.
Turn off the radio and stop taking cell calls a mile or so before reaching the house.
Think about the upcoming inspection process.
Tune the inspector's mind to the task at hand.
Observe the neighborhood, age of houses, quality of maintenance, heavy trees (funny winds and flue draft problems or squirrels in chimneys).
What to Do When Arriving at a Building Inspection
On arriving at a building inspection in preparation for inspection of the heating system or any other building or building system or component here are
some steps that aid in assuring that the inspector's attention will be fully focused on the job at hand:
Turn off the car ignition and sit for just a moment.
Calm yourself for a moment before getting out of the car, before stepping into the sea of seller and buyer anxiety and sometimes the cold acrid wind of realtor fear.
CONTROL ATTENTION - How to Focus Attention to Assure a Thorough Heating System Inspection
The Heating System or Home Inspector MUST Control the Inspection Process
The inspector must be in control of the process.
Do not permit an owner or realtor to lead the inspection by area, topic, nor discussion. These parties are not inspection professionals and
their interests may not coincide with those of the building buyer or inspector, and they can distract and prevent an inexperienced inspector from making important observations.
How to politely regain inspection control: If the realtor or owner says "We'll start the inspection in room A" the inspector should usually reply "sorry but I always begin at X" - some other
area, and head in the direction of "X". Do this even if you intended to head for "A". [Thank you John Annunziata, P.E., NY METRO ASHI 1986 for this tip]
The inspector should invite questions and can be aided when a client notices and asks about something that the inspector has not addressed. More eyes
looking are always helpful
Do not permit distractions. Focus must be on the building and its components, then on clients to assure that the inspector's explanations are understood.
How to pay close attention for hours at a time: without the audible use of Zen mantras or other eyebrow-raising behavior the inspector must be calm, relaxed, and completely focused on the process of inspection.
How to Pay Attention During the Heating System Inspection
Home inspection is paying attention to everything, simultaneously. Each observation at every step might reveal a key which will trigger an important discovery later in the inspection.
The inspector must focus on a sequence of examination of minute details.
Simultaneously the inspector must remain open to the unexpected findings or ideas. The unexpected may be suggested by a detail under examination or it may intrude from the inspector's peripheral.
It is easier to notice the presence of a defect of commission (leaking relief valve) than a defect of omission (no relief valve installed). "Psychology and nothing," Eliot Hearst, American Scientist, Sept.-Oct. 1991 pp 432-443. Every home inspector can improve his/her inspection technique by reading this article. Recognizing and learning from absence, deletion, and nonoccurrence are surprisingly difficult. Thinking through sequences of construction or of operation of equipment can help find omissions.
Use techniques to stay focused, to avoid mistakes,
How to avoid heating system errors and omissions:
Balance Inspection Procedure & Randomness: Practice a balance between an orderly method or procedure
which assures completeness and sufficient random steps in the process to avoid becoming routinized.
When an inspection is done by "routine" or "habit" the inspector sees only what is in the habitual mental "list".
Do not rely only on written heating system inspection checklists: Otherwise the inspector will observe only what's on the checklist and may miss glaring defects. Inspect the house and use your checklist to record it easily. Do not fit the house to the checklist.
Deliberately vary the inspection order and routine:: once an inspectors heating system inspection procedure is well established and familiar s/he should deliberately vary some of its components at every inspection. Change an order, reverse a sequence.
Heating System Inspection Final Check Thought Process
Hot heating water movement from house supply into boiler, through circulating equipment.
Fuel movement from tank through burner up flue and chimney.
Air movement into house and to burner and up flue and chimney.
Air movement inside duct work (for furnaces)
Complete operation sequence reviewed?
Other building conditions observed which raise questions? wet basement, poor housekeeping, poor maintenance, extensive building additions may stretch boiler capacity, ...
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Domestic and Commercial Oil Burners, Charles H. Burkhardt, McGraw Hill Book Company, New York 3rd Ed 1969.
National Fuel Gas Code (Z223.1) $16.00 and National Fuel Gas Code Handbook (Z223.2) $47.00 American Gas Association (A.G.A.), 1515 Wilson Boulevard, Arlington, VA 22209 also available from National Fire Protection Association, Batterymarch Park, Quincy, MA 02269. Fundamentals of Gas Appliance Venting and Ventilation, 1985, American Gas Association Laboratories, Engineering Services Department. American Gas Association, 1515 Wilson Boulevard, Arlington, VA 22209. Catalog #XHO585. Reprinted 1989.
The Steam Book, 1984, Training and Education Department, Fluid Handling Division, ITT [probably out of print, possibly available from several home inspection supply companies] Fuel Oil and Oil Heat Magazine, October 1990, offers an update,
Principles of Steam Heating, $13.25 includes postage. Fuel oil & Oil Heat Magazine, 389 Passaic Ave., Fairfield, NJ 07004.
The Lost Art of Steam Heating, Dan Holohan, 516-579-3046 FAX
Principles of Steam Heating, Dan Holohan, technical editor of Fuel Oil and Oil Heat magazine, 389 Passaic Ave., Fairfield, NJ 07004 ($12.+1.25 postage/handling).
"Residential Hydronic (circulating hot water) Heating Systems", Instructional Technologies Institute, Inc., 145 "D" Grassy Plain St., Bethel, CT 06801 800/227-1663 [home inspection training material] 1987
"Warm Air Heating Systems". Instructional Technologies Institute, Inc., 145 "D" Grassy Plain St., Bethel, CT 06801 800/227-1663 [home inspection training material] 1987
Heating, Ventilating, and Air Conditioning Volume I, Heating Fundamentals,
Boilers, Boiler Conversions, James E. Brumbaugh, ISBN 0-672-23389-4 (v. 1) Volume II, Oil, Gas, and Coal Burners, Controls, Ducts, Piping, Valves, James E. Brumbaugh, ISBN 0-672-23390-7 (v. 2) Volume III, Radiant Heating, Water Heaters, Ventilation, Air Conditioning, Heat Pumps, Air Cleaners, James E. Brumbaugh, ISBN 0-672-23383-5 (v. 3) or ISBN 0-672-23380-0 (set) Special Sales Director, Macmillan Publishing Co., 866 Third Ave., New York, NY 10022. Macmillan Publishing Co., NY
Installation Guide for Residential Hydronic Heating Systems
Installation Guide #200, The Hydronics Institute, 35 Russo Place, Berkeley Heights, NJ 07922
The ABC's of Retention Head Oil Burners, National Association of Oil Heat Service Managers, TM 115, National Old Timers' Association of the Energy Industry, PO Box 168, Mineola, NY 11501. (Excellent tips on spotting problems on oil-fired heating equipment. Booklet.)
R.E. Prescott Company, a producer of other REPCO™ residential and industrial products as well as a provider of design-build engineering services is at 10 Railroad Avenue, Exeter, NH 03833. Tel: 603-722-04321 or 888-786-7482. Trish O'Keefe from Prescott informed us (10/7/2009) that their company had nothing to do with the failed Repco heating boilers discussed at InspectAPedia.com. She wrote:
Our company manufactures & distributes residential water treatment equipment, including our Repco line of conditioners. We have a plumbing & heating supply dept as well. We are mistaken for the Repco Boiler company on a regular basis, most frequently in Oct. and Nov.
Any information you could give me on the other Repco company would be appreciated. We've assumed it is no longer in business, and we'd like to know that for sure. Many callers want to know where to get replacement parts and I would be glad to direct them if I knew...plus there's always a chance they might be interested in a Crown Boiler instead.
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
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.
Or choose the The Home Reference eBook for PCs, Macs, Kindle, iPad, iPhone, or Android Smart Phones. Special Offer: For a 5% discount on any number of copies of the Home Reference eBook purchased as a single order. Enter INSPECTAEHRB in the order payment page "Promo/Redemption" space.
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 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.
Links to our list of additional information on heating system inspection, repair, maintenance