Heating Problem Diagnosis: Heating System Inspection, Repair, Maintenance InspectAPedia® -
How to inspect a heating system furnace, boiler, electric heat, heat pump, or other heating equipment
How to diagnose loss of heat, cold radiators, cold furnace air, noises, smells, all other heating problems
Gas piping hazards, repairs
Carbon monoxide hazards
Furnace and boiler hazards, safety recalls
Oil tanks, how to find, inspect, test, remove buried and above ground heating oil tanks
Chimney and vent safety, product recalls, inspection; chimney soot & draft problem diagnosis, repair
How to save money on heating costs
Home inspection heating system inspection procedure & heating system report language
Questions & answers about heating systems: how to inspect, diagnose, & repair heaters , determine heating capacity, recognize unsafe conditions, and how to reduce heating costs.
These heating system articles answer questions about all types of building heating systems and describe how to inspect, diagnose, and repair heating system problems, how to cut heating bills, and heating system safety, heating system efficiency and heating trouble-shooting advice.
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In these heating system articles we explain how to inspect and detect all defects and hazards on heating systems, boilers, furnaces, and other equipment. Methods for saving on heating cost and on improving heating safety are included.
Heating safety hazards such as carbon monoxide gas leaks, unsafe furnaces, furnace and boiler recalls are addressed.
If you don't know whether your heat is provided by a furnace (hot air) or boiler (hot water), or whether your fuel is oil, gas, or electric,
and whether your heat is hot water, steam, or warm air, see HEATING SYSTEM TYPES.
Heating System Inspection Methods, Diagnosis, Safety, Repairs
These heating system inspection, diagnosis and repair articles describe the basic components of a home heating system,
how to find the rated heating capacity of an heating system by examining various data tags and components, how to recognize common heating system operating or safety defects, and how to save money on home heating costs.
We include product safety recall and other heating system hazards.
The limitations of visual inspection of heating systems are described. Contact us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution. Potentially very costly environmental hazards such as leaky oil tanks are explained in depth. Other environmental and indoor air quality topics affected by residential and light commercial heating systems are explored.
Heating System Inspection & Diagnosis Detailed Articles
See links at page left for complete index to online articles on heating system inspection, diagnosis, repair
Air Duct Systems for Heating & Cooling - duct defects, inspections, repairs, duct cleaning, flooded ducts, leaky air ducts, moldy duct systems, indoor air quality
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.
Boiler chemicals, steam and hydronic boiler water treatment chemicals. Also see Carbonic acid [below in this list]
Boiler Controls & Switches: a description of heating boiler controls and switches, what they do, how to set them, what problems to watch for
Boiler Leaks, Corrosion, Stains: where to look for leaks on heating boilers, which leaks are important, dangerous, costly, & what to do about leaks at a heating boiler
Carbonic acid (H2CO3) build-up in hot water heating systems can occur in areas where the pH of your boiler water is below 8.5 or where other heating system malfunctions cause this inorganic corrosive acid to accumulate in hot water piping. High carbonic acid, like excessive oxygen levels in heating water, can lead to hot water piping leaks, water damage, and loss of heat in the building. In a steam heating system, condensing steam dissolves carbon dioxide (CO2) to form carbonic acid that in turn corrodes piping. Ask your heating technician if your boiler water needs treatment or if your system needs additional venting equipment to remove excessive gases from the heating water. Treatment chemicals for acidic boiler water may include lime and soda ash (COH), phosphate, chelates, oxygen scavengers, neutralizing amines, or filming amines, all designed to protect the heating system boiler and piping from acidic corrosion. Details: see Boiler Chemicals 101 provided by NCDENR. Also see Boiler chemicals, steam and hydronic boiler water treatment chemicals.
CHINESE DRYWALL HAZARDS - corrosion risks to HVAC condensing and cooling or heating coils, possible corrosion risks to HVAC metal ductwork from corrosive gases produced by Chinese drywall.
CONDENSING BOILERS/FURNACES DAMAGE - review of damage to heat exchangers or flues caused by condensation & corrosi9on in high-efficiency furnaces and boilers; what about older heating equipment and duty cycle condensation?
FAN CONVECTOR HEATERS - HYDRONIC COILS - hot water to air heat for backup heat, water to air heat, cold spots, basements, crawl spaces, kickspace heaters, under counter heaters, and freezeproofing buildings
Fire dampers, and Heating and Cooling Air Duct Controls such as manual and automatic duct dampers, zone dampers, and fire dampers are discussed and distinguished at DRAFT REGULATORS - barometric damper
FUEL UNIT, HEAING OIL PUMPS - details about the types, installation, and inspection of heating oil fuel units or "oil pumps" used on heating boilers, furnaces, water heaters, and other equipment.
Hard water: if your heating system water supply is too high in mineral content, minerals may form scale that prevents heat transfer, increases heating cost, and damages the heating boiler or piping, even leading to clogging.
FURNACE HEAT EXCHANGER LEAKS describes how to test for unsafe warm air furnace heat exchangers - tests and procedures to detect dangerous leakage of flue gases and possibly carbon monoxide into building interiors
Hydrogen sulfide in heating water: causes corrosion in the heating system. High sulphur levels or H2S are typically removed by treating the incoming boiler water (and building water supply) with chlorination or filtration.
Iron in heating water: excessive iron in heating boilers causes deposits that can clog the system and lead to higher heating costs or even loss of heat or unsafe heating controls such as a clogged low water cutoff switch.
Heating Cost Reduction Advice: How to Save on Home Heating Costs - Book Review & Actual Heating Savings and Energy Savings Tips for homeowners and service technicians
HEATING SMALL LOADS - special advice for energy efficient home heating systems & heating system design to warm small areas
Heating Loss Diagnosis: How to diagnose loss of heat, when the oil burner, boiler, or furnace won't run, or when the system runs but heat is not delivered to the living area
MANUALS & PARTS GUIDES - HVAC - where to download heating, air conditioning, water heater, and other equipment installation and service manuals and users guides - free.
Odors From Heating Systems - a list of articles addressing the sources of odors produced by various types of heating systems - how to find, diagnose, and correct these possibly dangerous conditions.
OIL LINE SAFETY VALVES discuss fire safety valves that have a fusible link to prevent feeding heating oil to a building fire; these valves are also often used as oil piping shutoff valves for oil burner service.
Oil Tanks - The Oil Storage Tank Information Website: Buried or Above Ground Oil Tank Inspection, Testing, Cleanup, Abandonment of Oil Tanks
OIL TANK GAUGES - how to find, test, and read the gauge on a heating oil tank
Silica in heating water: high silica levels in heating boilers increases scale formation and increases heating cost or damaging the equipment. Water softening equipment or other treatment equipment is typically installed to address high silica in water.
SLAB INSULATION, PASSIVE SOLAR - how much insulation, where to put it, and where to put the vapor barrier below a heated floor slab
SOLAR ENERGY SYSTEMS renewable energy design and equipment for electrical, heating, and hot water; building designs for energy efficiency and reduction of heating and cooling costs.
Steam Heating Systems - care & maintenance, controls, diagnosis, & repair, safety devices
Thermal Tracking & Stains & Signs of Heat Loss how to recognize thermal tracking or thermal bridging & how to diagnose Stains on Ceilings & Walls, Building Air Leaks & Insulation Defects, as well as other indoor air quality or building concerns
Heating Cost Reduction Advice: How to Save on Home Heating Costs - Book Review & Actual Heating Savings and Energy Savings Tips for homeowners and service technicians, gas & oil heat money saving tips, thermostat tips, tuneup tips.
Heating Loss Diagnosis: How to diagnose loss of heat, when the oil burner, boiler, or furnace won't run, or when the system runs but heat is not delivered to the living area
SOLAR ENERGY SYSTEMS renewable energy design and equipment for electrical, heating, and hot water; building designs for energy efficiency and reduction of heating and cooling costs.
Thermal Tracking & Stains & Signs of Heat Loss how to recognize thermal tracking or thermal bridging & how to diagnose Stains on Ceilings & Walls, Building Air Leaks & Insulation Defects, as well as other indoor air quality or building concerns
Critical Defects
Critical defects which an inspector should not fail to detect when examining any building component or system
are defects which form an immediate, significant safety hazard or defects which are quite likely to involve
significant repair or replacement cost, and which involve components or systems which are necessary to occupy
and use the building. Methods for detection and diagnosis of these defects are discussed in this document
and in its references. Suggestions for inclusion or exclusion of items in this list are invited - see the
link "Contact Us".
Because the heating system inspection and related topics discussed here cover a rather broad range, I have not attempted (yet) to list specific critical defects on this summary page. However any inspection of the condition of heating equipment in buildings must include careful attention to:
Life Safety Hazards such as evidence of unsafe chimneys, missing or damaged safety devices (relief valves, emergency shutoffs), and visual evidence of dangerous overheating or leaks.
Responsibly conducted, an inspection of a gas-fired furnace, for example, might discover that the furnace has been exposed to severe rust-producing conditions which risk an unsafe heat exchanger and a carbon monoxide hazard which could be fatal to building occupants.
Even though the heat exchanger may not be visible, the contextual clues around the furnace, if they are visually obvious, should be translated into a level of concern by the inspector, and where appropriate, translated into a recommendation for action. This does not mean "failing" every furnace to be on the "safe side", it means responsible inspecting and reporting.
Costly defects such as evidence of a heating system at or near the end of its life of safe, reliable operation, or evidence of a buried oil tank which is likely to be old and for which there is no record of leak testing, should be reported.
Frequently Asked Questions (FAQs) about heating system installation, problem diagnosis or troubleshooting, and repair
Question: I'm trying to find how to determine the age of my Lennox gas furnace
I am trying to find the age of my lennox gas, gravity fed air, furnace model GN1-105C which the only thing I've had to do to it besides cleaning is change the thermo-couple in the last 40 years
Reply:
Jack, please see our article "How to Determine the Age & Life Expectancy of Heating Boilers & Furnaces" at AGE of HEATERS, BOILERS, FURNACES where we explain the decoding heating and cooling equipment data tags to learn the date of manufacture of the device. That article also refers you to some texts, including one free and visible here at InspectAPedia that offer more model/serial number decoding to see the equipment age.
Questions & Answers regarding this article
Questions & answers about heating systems: how to inspect, diagnose, & repair heaters , determine heating capacity, recognize unsafe conditions, and how to reduce heating costs.
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.
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Audels Oil Burner Guide, Installing, Servicing, Repairing, Frank D. Graham, Theo. Audel & Co., New York 1946, 1947, 1955 (out of print, copies occasionally available from antique book dealers and on EBay)
Boiler Chemicals 101, NCDENR, - Retrieved 12/24/2010, original source http://www.p2pays.org/ref/32/31321.pdf
Quoting from the North Carolina Division of Pollution Prevention and Environmental Assistance: The N.C. Division of Pollution Prevention and Environmental Assistance provides free, non-regulatory technical assistance and education on methods to eliminate, reduce, or recycle wastes before they become pollutants or require disposal. Contact DPPEA at (919) 715-6500 or (800) 763-0136 for assistance with issues in this fact sheet or any of your waste reduction concerns.
Thanks to Scott C. LeMarr, for sharing his file of keys to decode Furnace and Water Heater Age from the data provided on the manufacturer's equipment labels. Mr. LeMarr is
a professional home inspector, Certified Professional Inspector/President,
MASTER Indoor Environmental Specialist (MIES).
Vice President of Wisconsin NACHI. He and his company, Honest Home Inspections, LLC. can be reached at
262-424-5587 or by email to scott@honesthomeinspections.com
Passive Solar Design Handbook Volume I, the Passive Solar Handbook Introduction to Passive Solar Concepts, in a version used by the U.S. Air Force - online version available at this link and from the USAF also at wbdg.org/ccb/AF/AFH/pshbk_v1.pdf
Passive Solar Design Handbook Volume II, the Passive Solar Handbook Comprehensive Planning Guide, in a version used by the U.S. Air Force - online version available at this link and from the USAF also at wbdg.org/ccb/AF/AFH/pshbk_v2.pdf [This is a large PDF file that can take a while to load]
Passive Solar Handbook Volume III, the Passive Solar Handbook Programming Guide, in a version used by the U.S. Air Force - online version available at this link and from the USAF also at wbdg.org/ccb/AF/AFH/pshbk_v3.pdf
"Passive Solar Home Design", U.S. Department of Energy, describes using a home's windows, walls, and floors to collect and store solar energy for winter heating and also rejecting solar heat in warm weather.
"Solar Water Heaters", U.S. Department of Energy article on solar domestic water heaters to generate domestic hot water in buildings, explains how solar water heaters work. Solar heat for swimming pools is also discussed.
"Heat-Transfer Fluids for Solar Water Heating Systems", U.S. DOE, describes the types of fluids selected to transfer heat between the solar collector and the hot water in storage tanks in a building. These include air, water, water with glycol antifreeze mixtures (needed when using solar hot water systems in freezing climates), hydrocarbon oils, and refrigerants or silicones for heat transfer.
"Solar Water Heating System Freeze Protection", U.S. DOE,using antifreeze mixture in solar water heaters (or other freeze-resistant heat transfer fluids), as well as piping to permit draining the solar collector and piping system.
"Solar Air Heating" U.S. DOE also referred to as "Ventilation Preheating" in which solar systems use air for absorbing and transferring solar energy or heat to a building
"Solar Liquid Heating" U.S. DOE, systems using liquid (typically water) in flat plate solar collectors to collect solar energy in the form of heat for transfer into a building for space heating or hot water heating. The term "solar liquid" is used for accuracy, rather than "solar water" because the water may contain an antifreeze or other chemicals.
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.
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.
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.)
"Scale formation in water heaters and methods of prevention", Krappe,
Justus Maximilian, Engineering experiment station. Gas engineering
bulletin; no. 6; Research series; no. 74; On cover: Engineering
bulletin, Purdue university. Vol. xxiv, no.
3a. June, 1940 (Layfayette Indiana) commonly referred to in some references as "Purdue University Bulletin No. 74" - thanks to researcher Robyn Goldstein for the full citation. LCCN: 40028844 & OCLC: 1038544 - Water analysis, water softening, hot-water supply. 27pages. You can obtain this document through your local library.
(full copy file at InspectAPedia 3/31/2010)
Purdue B074 can be hard to locate online.
Also Bradford White Corporation (a manufacturer of water heaters) has published excerpts from that document, available at Purdue_B074_BradfordW.pdf
Links to our list of additional information on heating system inspection, repair, maintenance
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