Furnace sketch (C) Carson Dunlop Associates Oil Heat Furnace Defects List & Home Inspection Education

  • DEFECTS LIST - HEAT FURNACE OIL - CONTENTS: Oil-fired heating warm air furnace inspection points and defects list. Lists of important oil-fired forced air furnace defects for residential buildings. What does a home inspector need to know about oil-fired furnaces & heating system defects? Home inspection training and education curriculum recommendations for oil-fired forced air heating furnace systems
  • POST a QUESTION or READ FAQs about home & building inspection courses, standards, & defect checklists for oil fired heating furnaces

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This article lists significant oil-fired heating furnace (warm air system) defects, definitions, and home inspection education topics.

The building defects and inspection points listed in these articles also guide homeowners and home buyers to building areas that merit careful attention and often point areas of safety concern or important maintenance and repair tasks. Page top illustration of an oil fired furnace courtesy of Carson Dunlop Associates.

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Home Inspection Education Curriculum - Heating: Oil Fired Furnaces

Readers should see HEATING SYSTEMS for our complete list of articles on this topic. Also see HOME & BUILDING INSPECTORS & INSPECTION METHODS.This article series, beginning at BUILDING DEFECTS LISTS, provides lists of common building defects and basic defect knowledge that also outline recommended curriculum content for home inspector education.

Watch out: these inspection lists do not list all possible defects for the systems discussed, and not all home or building inspectors will examine all of the items listed here. CONTACT us to suggest corrections or additions to articles at this website.


These curriculae and building defect lists are based on smilar curriculum documents first prepared by Joe Scaduto, an ASHI member who prepared course material for Northeastern University's Building Inspection Certificate program in 1988, subsequently by DF, InspectApedia's editor, for New York University ca 1988 and later, with others, recommended to ASHI, the American Society of Home Inspectors. ASHI did not adopt this material though currently that association as well as others offer extensive HOME INSPECTOR EDUCATION material. The curriculum and lists of defects are informed by additional analysis of the process of home inspection that was developed beginning Calgary, AB for Canadian and U.S. home inspector education and certification examinations in 1997. Other early contributors to home inspection education in the U.S. and Canada include Dr. Jess Aronstein, Alan Carson, Mike Casey, Mark Cramer, John Cox, Dwight Barnett, Douglas Hansen, Rick Heyl, Larry Hoytt, Bill Merrill, Kevin O'Malley, Dennis Robitalille, Keith Peddie, Pat Porzio, Roger Robinson.

4.2   Oil Fired Warm Air Furnaces Inspection Recommendations & Typical Defects List

4.2.1 Knowledge Base for Oil Fired Warm Air Furnaces Inspection

1.    List the materials, function and location of the components of a typical oil fired forced air furnace including ? the fuel storage and supply system, burner, heat exchanger, draft regulator(barometric damper), vent connector, combustion air supply, cabinet, controls, ducts, registers, and grills.

2.    Describe the features of  adequate installation and repair technique for oil fired furnaces.

3.    Define the following terms: oil safety valve, fire safety valve, atomizing oil burner (gun type burner), electrode, flame retention head, refractory (fire pot), blast tube (draft tube), transformer, fuel pump, ignition transformer, primary control (primary controller, stack relay, primary relay), flame sensor (Fire-eye, photo cell, cad cell), barometric damper (draft regulator), vent connector, side wall venting, automatic vent damper.

4.    Describe the normal operating cycle of an oil fired forced air furnace from call for heat to shut down.

5.    Outline the typical life expectancies of oil fired warm air furnaces.

6.    Identify the codes or standards which apply to oil fired appliances and warm air furnaces in your area.

4.2.2 Inspection Skills Oil Fired Warm Air Furnaces Inspection

1.    Describe the inspection procedure for oil fired warm air furnaces.

2.    Identify the following common defects listed on the next page.

3.    Describe the implication of each defect.

4.    Identify the safety issues for the inspector and occupant of the home(fire, oil spill, combustion product, pollution, injury due to moving parts).

5.    Communicate findings to client verbally and in writing, recommending corrective action where needed.

List of Typical Defects in Oil-Fired Forced Air Heating Furnaces

Heating Oil Supply, Burner, Venting, Typical Defects

Typical Oil Tank Defects                  

• Empty                      

• Leakage                    

• Located outside, not suitable for outdoor use

• Rusting                    

• Underground (warnings)

• Unsafe location (clearance distances, unprotected)

• Abandoned

• Damaged or corroded  

Primary Controller, Typical Defects

• Tripped

Typical Defects in the combustion chamber liner ("refractory or fire pot")

• Crumbling, cracked, collapsed

• Saturated

Typical Defects at Oil Tank Fill & Vent Piping

• Leak  

• Missing caps 

• Undersized vent

• Plastic

Typical Defects in Barometric Dampers, Draft Regulators     

• None installed (missing)

• Shared

• Improper location

• Inadequate draft air

• Inoperative

• Misadjusted    maladjusted  JDG

• Rusting

• Spillage

Oil Supply Piping Defects                  

• Missing

• Corrosion, damage, crimped         

• Leak                               

• Undersized

• Unprotected 

Flue Gas Venting System Typical Defects

• Improper material

• Inadequate combustible clearance

• Poor support

• Poor slope

• Poor connections

• Poor manifolding

• Poor insertion into chimney

• Rust, dirty, obstructed

• Vent connector too big, too small

• Vent connector too long

Dead end Flues

Heating Oil Filter Typical Defects                      

• Dirty                            

• Leak                             

• Missing                           

Typical Combustion Air Defects                                                                                  

• Inadequate combustion air         

Typical Oil Burner Defects                                       

 • Dirty

• Incomplete combustion – soot

• Inoperative

• Leaking  

• Short cycling 

• Too close to combustibles

• Vibrating, noisy

Mid-Efficiency Oil Furnaces, Typical Defects

• Corroded vents

• Excess temperature rise

• Poor vent location, arrangement

• Reliability

Typical Defects in Oil-Fired Forced Warm Air Heating Furnaces

Electronic Air Cleaner / Filter Defects

• Damaged cells

• Dirty

• Improper orientation

• Inoperative

• Mis-wired

• Missing components

Air Handler Cabinet Defects                    

• Combustible clearances 

• Mechanical damage

• Missing components              

• Obstructed air intake            

• Rust                             

• Scorching                        

Thermostat Defects for Forced Air Oil Fired Heating Systems                 

• Anticipator problems

• Damaged

• Dirty                             

• Loose                            

• Not level                        

• Poor adjustment or calibration    

• Poor location                                                        

Humidifier Defects on Forced Air Oil Fired Heating Systems    

• Clogged pad, mesh or nozzle

• Dirty

• Inoperative motor or solenoid valve

• Leaks

• No duct damper

• Poor location

Blower Assembly Defects on Forced Air Oil Fired Heating Systems                                   

• Dirty

• Fan belt loose, worn, damaged    

• Inoperative                       

• Noisy                            

• Overheating                      

• Poorly secured                   

• Running continuously             

• Rust                              

• Too small                        

• Unbalanced or vibration                                           

Duct & Register Defects on Forced Air Oil-Fired Heating Systems     

• Balancing damper adjustment

• Dirty, obstructed collapsed

• Disconnected or breached  JDG or damaged ducts

• Excessively long runs, excessive elbows

• Wire or pipes in ducts

• Registers or grilles (for return air) in garage

• Rusting or dirty

• In-slab ducts

• Mechanical damage

• Leaky joints

• Insulation missing, damaged

• Filter problems

• Undersized

• Weak airflow

Fan Limit Switch Defects on Forced Air Oil-Fired Heating Systems

• Improperly wired                  

• Missing cover                    

• Scorching                        

• Set wrong or defective           

• Fan problems

Combination (water to air) Heating System Defects - Oil Fired Heaters

• Cabinet problems

• Control problems

• Domestic water too hot

• Inadequate heat for house

• Inoperative, inefficient pumps

• Inoperative water heater

• Leaking, clogged coils

• Water control problems

Watch out: these inspection lists do not list all possible defects for the systems discussed, and not all home or building inspectors will examine all of the items listed here.


Continue reading at FURNACES, HEATING or select a topic from the More Reading links shown below.


Or see HEATING SYSTEMS for our complete list of articles on this topic.

Suggested citation for this web page

DEFECTS LIST - HEAT FURNACE OIL at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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