WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM December 2012 Learning Objectives By attending this session participants will be able to Explain the basic principles of combustion distribution and venting and be able to recognize safetyrelated problems ID: 776150
Download Presentation The PPT/PDF document " Combustion Appliances WEATHERIZATION EN..." is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
Combustion Appliances
WEATHERIZATION ENERGY AUDITOR SINGLE FAMILY
WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM –
December 2012
Slide2Learning Objectives
By attending this session, participants
will be able to:
Explain the basic principles of combustion, distribution, and venting and be able to recognize safety-related problems.
Describe the health and safety issues related to combustion equipment.
List the basic steps of visual and diagnostic combustion appliance safety and efficiency inspection.
Cite test procedures for vented and non-vented appliances.
Summarize the relationship between combustion safety problems and poorly designed or non-code-compliant vent systems.
Describe worst
case combustion appliance zone testing.
Slide3We test to assure:Health and safety.Building integrity.Comfort.Energy efficiency.
Why Test Combustion Appliances?
Photo courtesy of New River Center for Energy Research and Training (NRCERT)
Slide4Combustion Basics
Combustion appliances
Slide5The Combustion Triangle
Requirements for Combustion (Burning):
Combustion appliances
Slide6Complete Combustion Results in:
Triangle of Combustion Products
Slide7Complete Combustion Occurs…
When all the fuel is burned with sufficient oxygen to produce carbon dioxide and water vapor.
Complete Combustion
Combustion
by-products
Slide8CO occurs when:The ratio of fuel to oxygen is either too high to permit the complete formation of CO2 or...The temperature is too low to permit complete burning to occur.It is caused by:Too much fuel for the amount of oxygen.Not enough oxygen for the amount of fuel.Not enough heat (flame impingement).
Carbon Monoxide from
Incomplete Combustion
Slide9C
ombustion, Distribution & Venting
Return Air
Main Burner
Supply Air
Vent
Combustion Gases
Dilution Air
Heat Exchanger
Gas Valve
Combustion Air
Slide10What do we inspect on combustion appliances?Chimney safetyVent pipesWiringHeat exchangerDistribution systemsCombustion air
What to Inspect - Visual
Photo courtesy of PA Weatherization Training Center
Slide11Fuel Leak Testing #1
Use a calibrated gas leak detector to locate fuel leaks.
Photo Courtesy of NRCERT
Bacharach
www.bacharach-inc.com
Slide12Fuel Leak Testing #2
Test all joints,
valves,
and fittings.
Use soap bubbles to
confirm a leak.
Photos Courtesy of NRCERT
Combustion appliances
Slide13Fuel Leak Testing #3
Gas leak detector for
gas and propane.
Visual inspection and the personal sniff test for fuel oil.
Photos Courtesy of NRCERT
Slide14Photos Courtesy of NRCERT
Is insulation on wiring missing or deteriorated?
Is the heating system on its own circuit?
Are wires properly clamped, connected, and enclosed?
Inspection – Wiring
Slide15Clearance to Combustibles
Oil and Wood Gas Single Wall 18”Single Wall 6”Double Wall Super Six, Dura Vent 6”Double WallB-Vent or B-W Vent 1”Manufactured Chimney 2” or per Manufacturer Instructions
Photo Courtesy of NRCERT
Combustion appliances
Slide16NFPA-54 states that combustion air must be provided for any combustion zone where the collective fuel input exceeds 1,000 Btu per 50 cubic ft.Make-up air can be provided from outdoors or from other zones of the building.
Combustion Air
Photo Courtesy of NRCERT
Slide17Change out the furnace filter and educate the
client about checking it periodically.
Filter Replacement
Photo Courtesy of NRCERT
Photo Courtesy of PA Weatherization Training Center
Combustion appliances
Slide18Blower Maintenance
Clean the blower.
Photo Courtesy of NRCERT
Photo Courtesy of
PA Weatherization Training Center
Combustion appliances
Slide19Rust on the draft hood of a natural gas furnace is evidence of severe spillage of flue gases.
Soot stains at the inspection port of an oil fired boiler indicate the need for a tune up.
Combustion Safety Problems
Photos Courtesy of
PA Weatherization Training Center
Combustion appliances
Slide20What do we test on combustion appliances?Fuel leaksFuel input rateSufficient combustion airWorst case draftCarbon monoxideCombustion efficiency
What to Test – Diagnostics
Photo Courtesy of NRCERT
Slide21Photo courtesy of Bacharach Inc.
Combustion analyzers should be able to measure:
Flue gas oxygen contentFlue gas temperatureAmbient temperatureFlue gas carbon monoxideCombustion efficiencyFlue gas carbon dioxide contentFlue gas air-free or as measured CO content
Testing Equipment - Criteria
Combustion appliances
Slide22Draft gauge
Smoke tester (for oil)
Selected Testing Equipment
Inspection mirror
Digital probe thermometer
Combustion appliances
Photo courtesy of Bacharach Inc.
Photo courtesy of Bacharach Inc.
Photo courtesy of Bacharach Inc.
Photo courtesy of Omni Controls
Slide23If you’re not testing, you're guessing!
Testing Equipment
Photo Courtesy of NRCERT
Combustion appliances
Slide24Unvented Space Heaters
Unvented space heaters release all of their combustion byproducts into the home. In addition to carbon dioxide and water vapor, compounds of carbon monoxide, excess air, and sulfur dioxide will be present.
Photos Courtesy of NRCERT
Combustion appliances
Slide25Visual Assessment –
Space Heaters
WPN 11-6: Space Heater PolicyNo weatherization work allowed where unvented gas or liquid fuel space heater is primary heat source.Removal and replacement of such heaters with vented, code-compliant heating systems prior to weatherization is strongly encouraged.Input rating must be at or below 40,000 BTU/hr.WAP funds may only replace primary heating system, e.g. unvented with vented, code-compliant system. May not replace unvented space heaters left in home as secondary units with code-compliant unvented units.Mobile homes must be vented outside.
Photo Courtesy of NRCERT
Combustion appliances
Slide26Why Test Gas Cook Stoves?Elevated levels of CO are common.People often use them as a heat source.CO kills.Knowledge implies action.
Cook Stove Testing
Photo Courtesy of NRCERT
Slide27Gas Cook Stove Testing
Measure
the CO content in ambient air and visually assess the flame and condition of the burners.
Photos courtesy of NRCERT
Mobile Home Assessment
Slide28Gas Cook Stove Testing
Insert the probe of the analyzer
into the oven vent and read the CO content after the oven has
warmed.
Prepare the oven for a test by removing stored items, aluminum foil, etc.
Photos courtesy of NRCERT
Mobile Home Assessment
Slide29Furnace Testing Protocol
Furnaces must be tested to assess:Safety (fuel leaks, clearances, etc.).Flue gas temperatures.Oxygen (O2) or Carbon dioxide (CO2).Carbon monoxide (CO) levels.Draft.Condition of the heat exchanger.
Photos Courtesy of
PA Weatherization Training Center
Open-ended duct
Single wall flue for oil heat.
Combustion appliances
Slide30Furnace Testing Methods - Visual
Check for:
Dirt and debris.
Burner alignment.Soot, evidence of flame roll-out.Heat-exchanger condition.Vent pipe and roof termination.Gas or oil leaks.Wiring condition.Condition of air filter.
Cracked heat exchanger
Combustion appliances
Photo Courtesy of NRCERT
Slide31Heat Exchanger Leakage Testing
Test methods:Look for flame damaged areas on the heat exchanger.Look for rust on the burner ports.Measure flue gas concentration before and after blower starts.There should be no more than 1% oxygen change when the blower starts.Observe change in draft, CO or flame when blower turns on.Look for flame damaged areas on the heat exchanger.
Photo Courtesy of NRCERT
Damaged area of heat exchanger
Combustion appliances
Slide32Use a strong light and an inspection mirror.
Is the heat exchanger rusty? Are there cracks?
Inspection – Heat Exchanger
Photo courtesy of Bacharach Inc.
Slide33Find the worst case depressurization in the CAZ.Under worst case conditions conduct:Spillage testDraft testCO testPerform at the time of the audit and at the end of each work day.Deactivate appliances until hazard is fixed
Worst Case Combustion Safety Testing
Conduct these tests for vented systems only!
Slide34Record outdoor temperature.Clean dryer lint filter and furnace filter.Deactivate all combustion appliances.Close all exterior doors and windows.Open interior doors containing exhaust fans.Close all other interior doors.
Setting Up Worst Case Conditions
Slide35Record the pressure difference of the CAZ with respect to outdoors using a manometer. Operate all exhaust devices.Record the pressure difference of the CAZ with respect to outdoors.Conduct CO and spillage tests under worst case conditions.Open and close interior doors (including door to CAZ).Repeat for all other vented appliances.Return dwelling, exhaust fans, and combustion appliances to normal settings.
Conducting a Worst Case Test
Slide36Test for Spillage
Photo Courtesy of PA Weatherization Training Center
No spillage after
two minutes of operation
Smoke stick at draft diverter
Combustion appliances
Slide37SpillageTest at vent openings, i.e., dilution air openings and barometric damper with smoke.COTest at appliance breech between appliance and first opening in vent connect or directly above heat exchanger.Condensing gas appliances – Test at vent termination.
Spillage, Draft and CO
Slide38Atmospheric Furnace
CO, Draft and Steady State Efficiency
80+ Induced Draft Furnace
Draft
CO
CO
& Draft
Combustion appliances
Illustrations courtesy
of Corporation for Ohio Appalachian Development (COAD)
Slide3990+ Condensing Furnace
CO and Draft Test Locations #1
Floor Furnace
Draft
CO
CO
& Draft
Combustion appliances
Illustrations courtesy
of Corporation for Ohio Appalachian Development (COAD)
Slide40CO and Draft Test Locations #2
Fuel Oil Furnace
Barometric Damper
Draft
CO
Photo courtesy of NRCERT
Combustion appliances
Illustration
courtesy of Corporation for Ohio Appalachian Development (COAD)
Slide41APPLIANCESuggested CO Action LevelsGas furnace, boiler, or water heater100 ppm, as measured or 400 ppm air freeOil-fired furnace, boiler, or water heater100 ppm, as measuredGas cook stove, Oven100 ppm, as measured
Carbon Monoxide Action Levels
Combustion appliances
Slide42Solve excessive depressurization or inadequate draft:Repair chimney obstructions, disconnections, or leaks.Properly size the vent, connector, or liner.Install a metal chimney liner and/or a wind-rated chimney cap.Seal leaks in the return ducts of the CAZ.Balance supply and return air by adding new returns or by adding passive return air openings to the main body of the house.Reduce capacity of large exhaust fans.Provide make-up air for dryers and exhaust fans.Provide combustion air inlet to CAZ.
Combustion Safety Problems - Fixes
Slide43Open Returns
Photo Courtesy of PA Weatherization Training Center
Open return
Disconnected draft hood
Combustion appliances
Slide44Measuring BTU Input
Turn on only the unit to be measured. Others should be off.
Time one revolution of smallest dial,
and compare to a calibration chart.
Any discrepancy with the rated input should be within 10% of the input rating.
Clocking the Gas Meter
Photos courtesy of NRCERT
Time one revolution of smallest dial
Combustion appliances
Slide45What’s Wrong with this Picture?
Photo Courtesy of PA Weatherization Training Center
From furnace
From hot
water tank
To chimney
Combustion appliances
Slide46Chimney and Vent Connectors
Chimney
Combustion gases mixed with room air
Vent
Gas heating appliance
Draft hood
Water heater
Draft diverter
Dilution air
Slide47A venting system should:Carry all combustion byproducts to the outdoors.Establish draft quickly.Be properly sized with minimal restrictions.Have long durability (corrosion resistance).Not overheat surrounding materials.Have adequate make-up air.
Venting Systems
Slide48Chimneys and Vents
Photo Courtesy of PA Weatherization Training Center
From hot
water tank
Chimney
Single wall vent
From furnace
Slide49Masonry chimneys.Type B vents – double wall, round.Type B-W vents – double wall, oval.Type L vents – more heat, corrosion resistant.Single wall metal – interior only.Plastic pipe vents – low temp condensing furnaces.
Vent Types
Photo courtesy of NRCERT
Masonry chimney and B-vent
Slide50Vent gas temperatureHeat loss from the ventHeight of the venting systemCapacity of the venting systemRestrictions in the venting systemAmbient temperatureNegative pressure in the CAZ
Factors That Affect Vent Operation
See a problem here?
Photo Courtesy of PA Weatherization Training Center
Slide51Chimney Specifications
Masonry chimney is too
short.
Photo Courtesy of PA Weatherization Training Center
Slide52Chimneys and vents should:Be connected and unblocked.Not have holes in the chimney or vent.Have a sound liner.Rise no less than 1/4” per linear foot in the direction of the outlet.Extend at least 3’ above the highest point at which they pass through the roof.Be the appropriate type and size for the combustion appliances.Be at least the same diameter as the exhaust port of the combustion appliance.
Chimneys and Vents #1
Slide53Chimneys and Vents #2
Chimneys and vents must not be blocked and must have no holes in the chimney or vent.
Missing cleanout
Blocked chimney
Photos Courtesy of PA Weatherization Training Center
Combustion appliances
Slide54Hole in Vent Connector
Improper Slope
Chimneys and Vents #3
Hole in vent
connector
Photos Courtesy of PA Weatherization Training Center
Improper
slope
Combustion appliances
Slide55No vent connector
Reduced vent connector out of compliance with
code
Chimneys and Vents #4
Reduced vent
connector
Photos Courtesy of
PA Weatherization Training Center
No vent connector
Combustion appliances
Slide56Water Heaters
Burn marks above the burner compartment are evidence
of
flame roll out.
Spillage of flue gases or insufficient draft is often a result of an improper installation such as this.
Photos Courtesy of PA Weatherization Training Center
Photos Courtesy of NRCERT
Combustion appliances
Slide57Testing Water Heaters #1
Atmospheric
Hot Water Tank
Test for draft above the
draft diverter.
Figure courtesy of COAD
Test for CO on both sides of the baffle
Photo courtesy of NRCERT
Combustion appliances
Illustration
courtesy of Corporation for Ohio Appalachian Development (COAD)
Slide58Test for CO directly into the breech of the unit on both sides of the baffle that runs up through the center of the tank.
On start up, time the amount of spillage. Then test draft above the draft diverter. Spillage should not exceed
one
minute.
Testing Water Heaters #2
Photos courtesy of NRCERT
Draft diverter
Combustion appliances
Slide59Photos courtesy of NRCERT
Chimney Liner
Combustion appliances
Slide60Understanding the basic principles of combustion, distribution, and venting will enable the auditor to recognize safety problems.Health and safety issues related to combustion equipment are some of the most important aspects of auditing a home.Visual and diagnostic combustion appliance safety and efficiency inspections and worst case CAZ testing reveal potentially dangerous situations and guide retrofit strategies. Practice appropriate test procedures for vented and non-vented appliances.Understanding the relationship between combustion safety problems and poorly designed or non-compliant vent systems is important to finding solutions.
Summary