LARGER VIEW of an octopus furnaceDetailed Step by Step Procedures for Inspecting Heating Systems
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How to inspect a heating system for problems, safety hazards, operating snafus: this document presents a very detailed methodology for inspecting residential heating systems with focus on heating boilers and furnaces, on assuring completeness, accuracy, and on maximum heating system defect detection. 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 heating system methodology discussed here includes both details specific to heating boilers (the full outline at "Contents") and more general complex-system inspection methods (listed immediately below).

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

Detailed Inspection Procedure for Heating Equipment

PREPARATION FOR HEATING INSPECTION - How to Prepare Properly to Assure a Thorough Heating System Inspection

These are steps in PREPARATION: a good procedural order when inspecting any complex system involves these steps: Look (inspect, test, operate), Think, Understand/Speculate-wait, Write, Speak. Also see HEATING INSPECTION CONCEPTS and HEATING INSPECTION PROCEDURE-GENERAL.

Preparation Begins Before the Heating System Inspection

Prior education & experience - prepares for the inspection by knowledge and attitude. Your inspection of heating equipment begins at or before the present seminar.

At the office - when order is taken (*)

  • Age of house--how old might the 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/multiple systems?
  • Type of house--large "H" ranch (one story) may have two separate furnaces
  • Buyer's concerns--comments about heating system volunteered by client?
  • House is occupied? winterized system, has it been left on?
  • Was work done by seller or amateurs? IE: "the owner converted the basement" [and did heating and electrical work?]

Driving to the inspection

  • Rested, healthy, attentive, mind on work?
  • If not, recognize that extra effort will be needed to tune your attention to the task about to begin.
  • Do not perform an inspection if you are seriously ill or distracted. Life-safety issues may be missed.
  • Turn off the radio a mile or so before reaching the house.
  • Think about the process.
  • Tune your mind to the task at hand.
  • Quiet time.
  • Observe the neighborhood, age of houses, quality of maintenance, heavy trees (funny winds and flue draft problems or squirrels in chimneys).

CONTROL ATTENTION - How to Focus Attention to Assure a Thorough Heating System Inspection or other Complex System Investigations

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.

Relaxation as an Aid to Attention During Heating System 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.
  • Exhale fully.
  • 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.

Take Control of the Inspection Process

  • The inspector must be in control of the process.
  • Do not permit distractions. Focus must be on the house, then on clients to assure your explanations are understood.

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.

Outdoor Points of Heating System Inspection

Outdoor heating system inspection from a distance

Viewpoint #1:--Distant (from the heating equipment): walking around the house, from the ground, just looking, notice and record:

Type of Heating Equipment Installed

Age of the neighborhood, other inspections done in the area, age of the house, may suggest type and even the brand of equipment which may be in place. Builders of developments often purchased many of the same brand and model for all the houses there.

What Heating Fuel Is or Has Been in Use

ASHI 9.2.A.1 The inspector shall describe the energy source Identify probable fuel source: oil, gas, electric, coal, wood, solar Notice the oil filler and vent, spills, and whether or not there is easy access to the oil tank filler pipe.

Also notice any evidence of old, possibly abandoned oil tanks (abandoned oil lines, protruding pipes, age of property, depressions in the soil), or of changes from one type of fuel to another (coal bins). These have potentially major cost implications (improperly abandoned oil tanks) or safety concerns (changes of fuel, unsafe chimneys).

Venting and possible hazards noted from outside:

[Examples of "distant" implications] ASHI 9.1.A.4 chimneys, flues, and vents Look for, then at the chimney. Is there a chimney? If not is there electric heat, direct-vent equipment, or no heat? Thinking about what chimneys do lets you understand the implications of your observations. These items are examples, not a comprehensive list.

If there is no chimney cap

  • is flue blocked by debris?
  • has wind-blown rain damaged the masonry interior?
  • has wind-blown rain run down chimney into flue vent piping and on into the equipment?
  • Did it cause rust damage? Fire chamber damage?

Masonry chimneys

  • damaged flue liner? Damage by condensation, frost, acid rain, sulphation (especially with gas-burning equipment)
  • Loose bricks?
  • Unlined single-wythe brick flues (still common in large cities)--if damaged, risk of fire, leaking flue gases, blocked flues. Look further in the attic and assure there's a cleanout or suggest vent connector be pulled to check for blockage.

Old stone chimneys

  • often stop at foundation, heaters were added, connected in to very base of chimney - easily blocked by fallen debris.
  • Signs of history of water entry (risk unsafe flue: blocked, fire risks - falling debris
  • possible damaged heating equipment (more likely for furnaces than boilers)


Potential Heating System Problems Seen from Outdoors

  • buried oil storage tanks or abandoned or leaky above ground or underground oil storage tanks
  • indoor tanks used outside
  • risks of water entering fuel from location of filler
  • fuel spills
  • leaks
  • ease of access to filler pipe
  • oil filler pipe left in place when the house converted to gas? (Potential very serious problem if oil is delivered by mistake.)

More information: see Oil Tanks Home which includes articles on spotting buried and abandoned or leaky oil storage tanks as well as oil tank leak reporting regulations and oil tank testing and abandonment advice.

Heating System Operation notes taken from outside:

  • Sooty chimney top or soot stains on roof: system has not been operating properly (see CHIMNEY INSPECTION DIAGNOSIS REPAIR.)
  • Soot washed off: system may have been repaired/replaced
  • Soot heavy and fresh or smoky exhaust seen, system currently needs service or repair
  • Watch out for Repco™ boilers which run sooty as they crash and can cause fatalities; watch for other recalled or unsafe heating equipment. See
    Safety Recalls
    BLUERAY Recall
    CHIMNEYS & Flues - Asbestos Transite
    Goodman HTPV RECALL
    Weil McLain RECALL

    [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.]
  • Heat seen rising from heating flue in July - the house may have a tankless coil for domestic hot water. If not, is the primary control set up properly?
  • Is there a separate oil-fired water heater using same flue? What's running making that exhaust? Reserve questions for later.


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