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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).

© Copyright 2012 InspectAPedia.com, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use page top links to major topics or use links at the left of each page to navigate within topics and documents at this website. Green links show where you are in a document series or at this website.

© Copyright Daniel Friedman 2008-1993 all rights reserved -- Tri-State ASHI Seminar -- Last update 08/03/2010 - first presentation November 6-7, 1993

Final heating system inspection checks in the boiler room:

Operate the Heating Equipment

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.
• Startup problems: noises, puff back, flapping barometric damper, vibrations
• 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

• 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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HEATING SYSTEM INSPECT DIAGNOSE REPAIR
  HEATING INSPECTION CONCEPTS
  HEATING INSPECTION PROCEDURE-GENERAL
HEATING SYSTEM INSPECTION DETAILS
  PREPARATION for Heating System Inspection
  ATTENTION CONTROL During Heating Inspection
  OUTDOOR INSPECTION of HEATING SYSTEM
  INDOOR INSPECTION of HEATING SYSTEM
  HEATING BOILER INSPECTION GUIDE
    HEATING SYSTEM INSPECTION SEQUENCE
    INSPECT HEATING CONTROLS
    INSPECT FOR HEATING BOILER LEAKS
    HEATING SYSTEM DEFECT SIGNIFICANCE
  ALTERNATE HEATING INSPECTION SEQUENCE
  FUNCTIONAL UNDERSTANDING of HEATERS
  HEATING FURNACE INSPECTION GUIDE
  FINAL BOILER ROOM INSPECTION CHECKS
  OIL BURNER INSPECTION GUIDE
  OPERATE THE HEATING SYSTEM
  HEATER OPERATING DEFECTS REPORT
  IMPLICATIONS OF HEATING CLUES
  FINAL HEATER INSPECTION REVIEW
  SET HEATING REPAIR PRIORITIES

• Information on Hydronic (hot water) Heating Boilers:
  • 
    BOILERS, HEATING
    BOILER CONTROLS & SWITCHES
    BOILER LEAKS CORROSION STAINS
    BOILER OPERATING PROBLEMS
• Information on Steam Heating Boilers & Steam Radiators
  • 
    STEAM HEATING SYSTEMS
      Low Water Cutoff Valves, Boilers
      Sight Glass, Steam Boiler
      Pressure & Temperature Settings, Controls
      Pressure Switch, Steam Boiler
      Steam Pressure Gauge
      Steam Vents
      LOW WATER CUTOFF CONTROLS
      Water Feeder Valves, Steam
• Information on warm air furnace heaters
  • 
    FURNACES, HEATING
    FURNACE CONTROLS & SWITCHES
    
    DUCT SYSTEM & DUCT DEFECTS
    DUCT SYSTEM DEFECTS
• Information on Radiant Heating: RADIANT HEAT Floor Mistakes to Avoid
• Information on Electric Heat: ELECTRIC HEAT
• Information on chimneys flues, vents, combustion air
  • CHIMNEY INSPECTION DIAGNOSIS REPAIR
    CHIMNEYS & Flues - Asbestos Transite Pipe
    DRAFT HOODS - gas fired
    DRAFT REGULATORS, DAMPERS, BOOSTERS
    FLUE VENT CONNECTORS
• Information on Heat Pumps - HEAT PUMPS

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.

• Carbon Monoxide Gas Toxicity, exposure limits, poisoning symptoms, and inspecting buildings for CO hazards
• DUST CONTAMINATION FROM HVAC? An Investigation of Indoor Dust Debris Blamed on a Heating/Cooling System Reveals Carpet Dust
• Fuel Oil & Oil Heating Magazine, 3621 Hill Rd., Parsippany, NJ 07054, 973-331-9545
• Goodman Furnace High Temperature Plastic Vent HTPV safety recall US CPSC notice
• Home Heating System Should Be Checked [for proper venting and for CO Carbon Monoxide Hazards - DJF]
• Inspection Procedures for Oil-Fired Heating Systems Detailed step by step approaches for inspecting complex systems]
• Lennox Pulse Furnace Safety Inspection/Warranty Program: Carbon Monoxide Warning
• Oil Tanks - The Oil Storage Tank Information Website: Buried or Above Ground Oil Tank Inspection, Testing, Cleanup, Abandonment of Oil Tanks
• Oil Tanks Above Ground, UL Standards, guidance for home owners, buyers, and inspectors
• Plastic Heating Vent Pipe & Other Heating Safety Recall Notices
• Weil McLain Model GV Gas Boiler/gas valve CPSC recall/repair
• 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 Steam Heating Systems", Instructional Technologies Institute, Inc., 145 "D" Grassy Plain St., Bethel, CT 06801 800/227-1663 [home inspection training material] 1987
• "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
• ...