Detailed Procedures for Inspecting Heating Systems InspectAPedia® -
Final Actions in the Step by Step Guide to inspection of heating boilers & furnaces for operating & safety defects
Heating system step by step detailed inspection procedure
How to understand & report the significance of findings during a heating system inspection
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This document presents the final inspection steps and operating suggestions when inspecting residential heating systems . The heating system inspection methodology involved is intended to be generalized to
the forensic diagnostic inspection of any complex system in order to have the highest probability of detecting
important safety or operating defects.
This sounds fancier than intended. Our object is to use an organized
procedure for inspecting for defects, without losing the ability to discover unexpected problems as well.
The methodology discussed includes both details specific to heating boilers (the full outline at "Contents")
and more general complex-system inspection methods (listed immediately below).
Final heating system inspection checks in the boiler room:
Operate the Heating Equipment
After all visual inspection. Avoids running dangerous systems, permits
explanation to client without background noise. Permits observations
of operation anomalies. ASHI 9.2.B. The inspector shall operate the system using normal operating controls such as using the thermostat - see BOILER OPERATING PROBLEMS
Heating System Operating Defects
Noises, smoke, soot, back pressure at inspection port (watch out for burns and fires if this port is opened), sloppy startup, rumbling, sloppy or delayed shutdown-flame lingers (very dangerous).
Feeling piping (hot!) can indicate if circulator is running--quick change in temperature vs convection.
Some leaks occur only at peak operating temperature--eg at relief valve.
Particularly in cold weather, if the system was on and running, observe and note that it was running normally when you last touched it. Witnessed. (Frost damage issues lurk here.)
Heating Equipment Malfunction & Implications
What are the Implications of the Clues of Heating System Defects that You Observed?
Leaks are never acceptable, anywhere. Leaking relief valves need immediate attention and repair (Leaking relief valve could be
due to water-logged expansion tank, improper control settings (temperature too high), improper automatic water feeder operation (pressure too
high), or defective valve (leaky). True, you only have to report the valve. Did you miss problems at the other components?) Corroded relief
valves also need test and repair/replacement
Relief Valves: Do not touch the heating boiler or water heater temperature or pressure relief valve - it may open and fail to shut down.
Corrosion on heating system parts: Do not pick at corrosion as you may start a catastrophic, un-stoppable leak requiring total system shut-down.
Tankless coils for making hot water: If there is different water pressure/flow observed in the kitchen in which the
hot water pressure is significantly less than cold, even before examining the building's mechanical systems you may
speculate that a tankless
coil installed may be installed. What other clues suggest that the local water supply may be hard in
minerals and that there may be a risk of clogged piping?
When the water supply is high in minerals, the hot water pipes or tankless coils clog up before cold water piping.
Is a water softener installed? Is there known "hard" water--have mineral deposits clogged the coil? Are there "cleanout"
plumbing fittings on the tankless coil piping? Does this suggest a history of clogging and acid-flush treatments? Can a clogged coil be repaired
or replaced? How severe was that rust you observed at the tankless coil mounting plate?
Remember that even a subtle clue like drips at the bottom of a relief valve discharge tube can have profound implications for the condition of the heating system. Clues make more sense when you understand how the equipment works, its operating cycle, and the function of each component.
See BOILER OPERATING PROBLEMS for an extensive list of heating system clues and what they mean for the safety, adequacy, or reliability of the heating system.
Thought Sequences for Final Heating System Check
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, ...
What's missing ?
Did we leave the system operating normally?
Heating Inspections: Safety Concerns for the Home Inspector
This section contains examples of steps to protect the inspector.
It does not address safety concerns for the client/occupant.ASHI 9.3.A. The inspector is not required to operate equipment
when weather conditions or other circumstances may cause equipment damage [or in the opinion of the inspector, may cause any sort
of unsafe condition (added by DJF, NOT ASHI Standards)
Do not turn on equipment which has been "shut down" - Possible open piping, unsafe wiring, leaks, unsafe chimney, fire risks.
Do not turn on equipment which has been switched off without explicit permission/instruction from a responsible party
Examine gauges (not entirely reliable) for unusual pressure or temperature conditions and do not permit such equipment to continue to operate
Do not operate equipment which does not appear to be vented properly; shut down equipment if, on operating it, you observe an apparently blocked flue
Do not operate equipment if the chimney is suspect--e.g. old single wythe unlined brick with visible damage in the attic or outside
Watch for flashback at inspection ports
Watch for electric shock at controls
Do not pick at corrosion
Do not test relief valve levers nor catch your sleeve on one ASHI 9.3.B. The inspector is not required to operate automatic safety controls
Do not light fires in coal or wood stoves to check draft, etc ASHI 9.3.C. The inspector is not required to ignite or extinguish solid fuel fires
Do not disassemble flue vent piping - risks of filth, unable to reassemble, etc. ASHI 9.3.D.1 The inspector is not required to observe the interior of flues [However often you can detect a blocked flue by looking through the barometric damper or by use of a mirror at the chimney cleanout. We recommend this step. -DJF] ASHI 9.3.D.2 The inspector is not required to observe fireplace insert flue connections [Normally not visible. Caution: there is frequently a hidden problem there.]
Be careful about disconnecting humidifiers to obtain access to furnace plenums: you may cut yourself on sheet metal, cause leaks in humidifier piping, cause spills. ASHI 9.3.D.3 The inspector is not required to observe humidifiers
But watch for humidifiers which leaked into and damaged duct work or onto and damaged a heat exchanger.
Avoid electric shock from the static charge at electronic air filters. ASHI 9.3.D.4 The inspector is not required to observe electronic air filters
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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.)
Links to our list of additional information on heating system inspection, repair, maintenance