Heating Systems Troubleshooting Repair: Maintenance Tips and Forensic Observations

337 Pages·2019·15.856 MB·English

by  John Certuse

Heating Systems
Troubleshooting & Repair
Maintenance Tips & Forensic Observations
John Certuse, P.E.
INDUSTRIAL PRESS, INC.
Industrial Press, Inc.
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Author: John Certuse, P.E.
Title: Heating Systems Troubleshooting & Repair:
Maintenance Tips & Forensic Observations
Library of Congress Control Number: 2019936359
© by Industrial Press.
All rights reserved. Published in 2019.
Printed in the United States of America.
ISBN (print): 978-0-8311-3640-6
ISBN (ePDF): 978-0-8311-9518-2
ISBN (ePUB): 978-0-8311-9519-9
ISBN (eMOBI): 978-0-8311-9520-5
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PREFACE
Most technicians leaving trade school are typically focused on passing a license exam
that, for the most part, addresses the installation of new equipment. The fact is, how-
ever, that over the course of their career, most of the work they perform is not install-
ing new equipment but, rather, repairing and maintaining older, existing systems. In
fact, some technicians may find themselves servicing equipment that is more than 100
years old (Figure P-1).
FIGURE P-1 Early Turn-of-the-Century Boiler Still in Use Today
Heating Systems Troubleshooting & Repair: Maintenance Tips & Forensic
Observations was written for those technicians installing new systems as well as for
those keeping older systems in proper working order. This book addresses many issues,
from boiler and furnace design to maintenance requirements of both the appliance
and the entire system heating the home. It also addresses the need to change attitudes
toward maintenance.
xiii
xiv PREFACE
Prevailing Attitudes
It has been said that we live in a “disposable society” where older appliances are rarely
repaired, with service technicians preferring to replace equipment needing more
advanced repairs. This attitude extends to home heating appliances that, due to the
fault of many, the homeowner included, are often left in service until small repairs are
no longer sufficient and the appliance requires replacement.
Then there is the commonly repeated philosophy of “If it ain’t broke, don’t fix it.”
Following this philosophy means only addressing repairs after equipment has broken
down and can result in unexpected consequences.
Where does the responsibility fall for boiler and furnace failures? That responsi-
bility belongs to everyone involved—but to different degrees. On rare occasions, it is
the manufacturer who is responsible, but more often it is the homeowners and those
employed to maintain these appliances.
The manufacturing and installation of an appliance are onetime occurrences,
performed and then done. Required preventative maintenance actions, however, are
ongoing and needed throughout the service life of the appliance.
The Importance of Preventative Maintenance
Residential boilers and furnaces are designed to run efficiently and reliably through-
out their design life. But to achieve longevity of life and efficient operation, the appli-
ance and system must be maintained through a regimen of preventative maintenance
actions throughout the equipment’s service life. It is these preventative maintenance
actions that determine the quality of the service life of the appliance as well as the
likelihood of unexpected equipment breakdown, costly equipment replacement, and
building damage.
A Team Effort
This book is intended to familiarize new service technicians of the overall mainte-
nance requirements of a heating system and to help them to realize that maintenance
is not limited to one particular component of a system without regard to others.
It’s a team effort to keep home heating appliances running safely, efficiently,
and reliably. The team includes both the manufacturers of appliances that provide
training and replacement components and the local service organizations that install
these appliances and perform needed repairs. More importantly, this team includes
the homeowner or building owner who must also support the service technician’s rec-
ommendations by scheduling annual maintenance allowing the technician to perform
needed maintenance repairs.
In the end, each party needs the other to make sure a residential heating appli-
ance is maintained to a level where it can not only achieve the intent of its original
design but also potentially exceed these expectations in performance and longevity.
PREFACE xv
The purpose of this book is not to replace existing manufacturer’s maintenance
directives but rather, to make the technician aware of their importance and the need
to be knowledgeable of the appliance’s ongoing maintenance needs throughout its
service life.
John Certuse, P.E.
May 2019
CONTENTS
Preface ..........................................................xiii
Acknowledgments ................................................ xvii
CHAPTER 1
Maintenance Theory . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Are You Really Maintaining Your Equipment or Just Fixing It? ............... 1
The Consequences of “Run It Until It Doesn’t Work Anymore” ............... 1
Installation to Code and Ongoing Maintenance ........................... 2
Three Levels of Maintenance ......................................... 3
The Maintenance Mix ............................................... 5
P-F Curves and P-F Intervals—Predicting the Time to Failure ............... 6
Furnace and Boiler Life Expectancy .................................... 6
Why Replace a Boiler or Furnace? ..................................... 7
The Degradative Effects of Ignored Preventative Maintenance ............... 11
The Building or Homeowner, the Technician, and
the Manufacturer Working Together! ................................ 13
Reference ........................................................ 14
CHAPTER 2
Heating System Types and Preventative Maintenance 15
Older Systems Still in Use Today ..................................... 16
Gravity Hot Air ................................................ 16
Gravity Hot Water .............................................. 18
Steam ........................................................ 19
Modern Heating Systems ........................................... 22
Forced Hot Water (Hydronic) ..................................... 22
Forced Hot Air ................................................. 23
v
vi CONTENTS
The Heat Pump System .......................................... 24
Hydro Air ..................................................... 24
Preventative Maintenance Pertaining to the Heat Distribution System ........ 24
Forced Hot Water System Maintenance .............................. 25
Steam System Maintenance ....................................... 27
Forced Hot Air Ductwork System Maintenance ....................... 29
Air-Conditioning Condensate System Maintenance .................... 30
References ....................................................... 32
CHAPTER 3
Installation to Code and Ongoing Maintenance . . . . . 33
Heating System Design ............................................. 33
Heat Load Determination ........................................... 33
Hydronic Heating System Design ..................................... 34
Appliance Placement ............................................... 34
Clearances to Combustibles........................................ 34
Confined Space of Installation...................................... 35
Chimneys and Direct venting ........................................ 39
Masonry....................................................... 39
Metal Flues .................................................... 39
venting and Appliance Categories..................................... 40
Direct venting .................................................... 41
Practical Considerations Addressing the Installation of Heating Systems....... 44
Boiler and Furnace Placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Access for Maintenance and Replacement............................. 44
Placement of Ductwork Diffusers and Baseboards ...................... 45
Freezing ....................................................... 46
References ....................................................... 47
CHAPTER 4
Boiler Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Boiler Construction ................................................ 49
Boiler Configuration—Wet Base and Dry Base Boilers .................... 50
Cast-Iron Sectional Boilers .......................................... 50
Cast-Iron Boiler Joining Methods .................................... 53
Section Gaskets ................................................... 53
Section Push Nipples .............................................. 54
Section Sealant, Rope Gaskets, or Sealing Cord .......................... 54
CONTENTS vii
Burner Type and Flame Geometry and Orientation Overview ............... 55
Tankless Heat Exchangers and Gaskets ................................ 57
Boiler Heat Exchanger Design Configurations ........................... 58
vertical Fire-Tube Cast-Iron Boiler (“Snowman”) ...................... 59
Power Burner–Fired (Oil or Gas Conversion–Fired Boiler),
Cast-Iron Sectional Boiler—Wet Base ............................. 61
Steel Fire-Tube (Oil or Gas Conversion–Fired) Boiler—Dry Base ......... 62
Power Burner–Fired (Oil or Gas Conversion–Fired Boiler),
Cast-Iron Sectional Boiler—Dry Base ............................. 65
Cast-Iron, Gas-Fired Boiler—Dry Base .............................. 66
Cast-Iron, Gas-Fired, Horizontal Sectional Boiler—Dry Base ............ 68
Copper Tube–Aluminum-Finned, Low-Water-volume,
Gas-Fired Boiler—Dry Base .................................... 69
Coiled Copper Tube–Aluminum-Finned, Low-Water-volume,
Gas-Fired Boiler .............................................. 71
Spiral, Low-Water-volume, Stainless-Steel, Gas-Fired, Condensing Boiler... 72
Cast Aluminum ................................................. 74
CHAPTER 5
Residential Furnace Design . . . . . . . . . . . . . . . . . . . . . 83
Warm Air System Types............................................. 83
Natural (Gravity) Hot Air Circulation................................ 83
Forced Hot Air Circulation ........................................ 83
Furnace Designs, Natural (Gravity) Hot Air ............................. 83
Floor or Wall Furnace ............................................ 84
Furnace Designs, Forced Hot Air...................................... 85
Airflow Direction.................................................. 85
Upflow Furnace ................................................. 85
Downflow Furnace............................................... 85
Horizontal ..................................................... 86
Energy Sources.................................................... 86
Electric Furnaces and Heat Pumps .................................. 87
Hydro Air...................................................... 88
Combustion Furnaces............................................... 89
Counter-Flow and Parallel-Flow Heat Transfer .......................... 89
Heat Exchanger Flow Path Length ................................. 90
Furnace Cabinet–Heat Exchanger Orientation......................... 90
Oil Furnace Design .............................................. 91
viii CONTENTS
Gas Furnace Design.............................................. 95
Soot Damage Caused by Malfunctioning Furnaces ....................... 102
Is it Really Soot from the Furnace? ................................... 102
Origins of Soot and Products of Combustion Other Than a Broken Heat
Exchanger .................................................. 103
Heat Exchanger Leaks and Cracks ................................. 104
Detecting the Presence of Leaks..................................... 105
Fan Test ...................................................... 105
Flame Test .................................................... 106
Product-of-Combustion Gas Detector .............................. 107
Smoke Candle Test ............................................. 108
Tracer Gas .................................................... 108
Gaining Access to the Leak (with the Furnace Still Assembled)............. 109
Access to the Heat Exchanger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
Common Locations of Heat Exchanger Failures....................... 110
visual and Other Inspection Methods............................... 115
References ...................................................... 123
CHAPTER 6
The Oil Burner and Fuel System . . . . . . . . . . . . . . . 125
Oil Burner Design ................................................ 125
Basic Components ............................................. 126
The Burner Body–Fan Assembly ................................... 127
The Fuel System ............................................... 129
The Ignition Transformer and Electrodes ............................ 130
Air Path and Air Adjustment ..................................... 131
Different Manufacturers ......................................... 132
Annual and Required Maintenance ................................... 134
Filters ....................................................... 134
Strainers ..................................................... 135
Nozzles ...................................................... 136
Electrodes .................................................... 138
The Primary Control ............................................ 139
The Firesides Cleaning .......................................... 141
The Combustion Performance Test ................................. 143
Typical Flame Retention Oil-Fired Burner Appliance Readings .......... 149
Service Records .................................................. 150
Combustion Performance Test Data ................................ 150
CONTENTS ix
Service History................................................. 151
CHAPTER 7
The Gas Burner System . . . . . . . . . . . . . . . . . . . . . . 155
The Air-Gas Mix ................................................. 155
Ignition Systems ................................................. 156
The Standing Pilot System ....................................... 157
Energy Losses Due to Pilot Flame Usage ............................ 158
Electronic Ignition ............................................. 159
Burner Design and Construction .................................... 166
Atmospheric or Tube Type ....................................... 166
Premix ....................................................... 170
Gas Burner Maintenance .......................................... 171
Appliance Maintenance ......................................... 171
Gas Pressure Check ............................................. 172
Burner Tube Inspection .......................................... 173
Combustion Chamber and Refractories ............................. 175
Combustion Performance Testing—Gas-Fired Appliances ................ 176
Carbon Monoxide in Combustion Gases............................. 177
Ambient Carbon Monoxide Measurement and Levels .................. 177
Appliance Combustion Parameters ................................. 178
References ...................................................... 182
CHAPTER 8
Soot Damage and Poor Indoor Air Quality in Homes . 183
Indoor Air Quality ............................................... 183
It’s Soot! What Is the Cause?........................................ 186
Conventional Failure Diagnosis.................................... 186
Common Locations of Accumulated Soot.............................. 192
Ghosting Soot Accumulations..................................... 192
Depressurization-Induced Combustion Reentry......................... 193
Advancements in Housing Material ................................ 194
Building Envelope Tightness ..................................... 194
Creation of a Negative Pressure Within the Building Envelope ........... 195
Combustion Appliance Issues and Depressurization.................... 196
Backdraft—Depressurization Reentry at the Appliance ................. 196
Depressurization Reentry Due to the Proximity of Discharge ............ 197
Paths of Reentering Emissions Flow ............................... 199