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The Importance of Combustion Testing
Testo Inc. - Jim Pritchard - Regional Sales Manager
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The Importance of Combustion Testing
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Testo Worldwide
Countries
R&D Engineers
Years of Excellence
Employees
Customers
Today’s Speaker
Jim Pritchard
Regional Sales Manager
Testo North America
A Global Manufacturer
• Largest manufacturer of Combustion Analyzers
• 60+ years of portable instrumentation development
& manufacturing experience
• 100+ R&D Engineers
• German/USA product development
• Innovative new products
• ISO 17025 Quality Standards
Draft (Set will look similar)
Draft (Set will look similar)
Agenda
• Why is Testing Important?
• Basic theories of combustion
• Hazards of Carbon Monoxide
• NOx Testing
• Making good measurements
• Care of Investments
maintenance, calibration & service
• Today’s Tools for Testing
Why Test?
• Customer Value – Product has been installed and or serviced according to
OEM recommendations and is operating a peak performance
• Professionalism – You are a professional service provider using proven
technology to provide a level of security that the service is completed
correctly, efficiently and safely the first time.
• Safety – You are insuring the work has been completed within scope of
local regulations and OEM recommendations for safe operation
• Liability Risk – With the implied safety, you take on some responsibility for
performance and CO danger. Testing provides record of conditions and
performance
• Profitability - You are required to provide a profit to your company by doing
the job right the first time in an efficient and productive time.
What does this mean to you?
• More Boiler/Furnace Tune-ups for energy assessment
• 1% increase in efficiency nets 1% fuel savings
• More awareness on Combustion Safety
• CO toxic to humans
• Dangerous fuel mixture
• Frequent Preventive Maintenance Scheduling
• Identify repairs and reduce downtime
• Demonstrate Environmental Compliance
• SO2, CO & NOx hazardous to the environment
The combustion process
is a balance between
Fuel, Air and Heat
(ignition source)
Fuel Air
Heat
Why test?
Basic Combustion Theory
• Air
• A blend of 79% Nitrogen & 21% Oxygen (O2)
• Fuel - A hydrocarbon compound CxHy
• Gas - Natural Gas or Methane: C6H4
• Liquid - Fuel oils, propane (LP or LPG)
• Solid – Wood or coal
• A source of ignition (spark)
• Or heat
Basic Combustion
Air + Fuel Combustion
Products
Why test?
Incomplete
Combustion
Fuel Air
CO
Smoke
ash
Complete
Combustion
Fuel Air
Carbon dioxide ( CO2)
Carbon monoxide (CO)
Sulfur dioxide (SO2)
Balance of oxygen (O2)
Nitrogen oxide NOx
Water vapor (H2O)
Smoke (oil systems)
Flue gas – by product of combustion process
Color, Sound,
Smell is not an
indication of good
or complete
combustion
Ideal trends-
• Lower CO
readings
• Increase O2
readings
• CO2 can be a
misleading
reading, it can be
high on either
side of ideal
zone
Incomplete Complete
Fuel Rich Excess Air
Flu
e g
as
co
mp
on
en
ts
Ide
al o
pe
rati
ng
ra
ng
e o
f
bu
rne
rsCO
CO2
O2
Eff.
Sto
ich
iom
etr
ic lin
e
Combustion Diagram – Stoichiometric Chart
Adjustment of variables puts you in the ideal Combustion Green Zone
Typical Readings
• Oil Fired Burners
Always Follow Mfr‘s Specifications (approved by Beckett)
Follow the 4 basic Steps:
1. Find a trace of Smoke
2. Measue the O2 or CO2
3. Open air to decrease CO2 or increase O2 by 1%
4. Leave at Zero Smoke
Which parameters are important to measure?
Net Temperature
Difference between stack and
primary air temperatures
Combustion efficiency rating
and heat loss
To determine excess air
(safety/efficiency)
Burner Safety & Emissions
Environmental Compliance(EPA)
Proper operation & Safety
Oxygen (O2)
Carbon Monoxide (CO)
NOx, NO, NO2, SO2
Stack Draft
Which parameters are important to calculate?
Combustion Efficiency
02, Temperature, Fuel
Reduce Fuel Cost - Savings
To determine Operating
Condition
Diluting effects of excess air
on Nox, SO2 and CO
Weight of pollutant (lbs/Mbtu)
Carbon Dioxide (CO2)
O2 Ref (3 to 15% O2)
Emission Conversions
Excess Air Extra Air for Combustion
What to test?
You can not always rely on your 5 human senses, you must have the proper tools for the job
Use a high quality and reliable combustion analyzer, which is capable of
the following readings so it can calculate flue gas components
Variables Measured
• Net Temperature difference
• Oxygen
• Carbon Monoxide
• Stack draft
Calculated Values
• Combustion Efficiency
• Carbon Dioxide
• Carbon Monoxide (air free)
• Excess air
• NOx
Input Measure Results
What to test?
• Control of variables is key to the combustion process
• Pressure: Confirmation or setting of gas pressures
• Excess Air: Needed to show complete combustion, but high values indicate high heat
stack loss – poor efficiency.
• Temperature (ambient and stack): Needed to determine efficiency
• Draft pressure: Confirms the proper venting of combustibles out of the flue, an
appliance has 5 minutes to prove draft under ANSI standards
• Oxygen (%O2): primarily determines complete combustion
• Carbon Dioxide (%CO2): the maximized value relative to efficiency and “ideal
combustion”, but does not necessarily indicate complete combustion.
• Carbon Monoxide (CO): lethal gas formed from incomplete combustion
• Efficiency: represents the total amount of heat available from the fuel minus the
losses from the gasses going up the stack
What is CO (Carbon Monoxide)?
• CO is an Odorless, Colorless, Tasteless, Poisonous (Toxic) gas that results from
incomplete combustion
Possible Sources of CO in the Building:
• Fuel burning furnaces and hot
water heaters
• Kitchen ranges & ovens
• Fireplaces
• Fuel burning space heaters
• Fuel burning boilers
• Attached garages
Incomplete
Combustion
Fuel Air
CO
CO Facts
• Carbon Monoxide (CO) can be lethal
• Over 500 deaths / year; 15,000 ER visits/ year
• 79% of deaths in residential settings
• 84% of deaths in the winter season
• 85% of deaths involve a heating system
• Natural Gas – furnaces, boilers, hot water heaters
• LP Gas appliances
• Oil fueled heating systems
• National problem, not regional
• 17% North East
• 33% South
• 30% Midwest
• 20% West
Carbon Monoxide Facts
• Odorless
• Colorless
• Tasteless
• Mixes well in air
• Poisonous
CO Symptoms
• Persistent headaches
• Dizziness, blurred vision,
nausea
• Fatique or drowsiness
• Shortness of breath and
confusion
• Feeling ill/tired at home,
but fine upon leaving
home or building
1 ppm = 1/1,000,000 parts
10000 ppm = 1 %
1000 ppm = 0.1%
100 ppm = 0.01 %
10 ppm = 0.001 %
1 ppm = 0.0001 %
So how big is a ppm?
Or consider a dropper of
oil in a 5000 gallon pool.
CO Health Effects
• 50 ppm OSHA Permissible Exposure Limit – 8 hours
• 200 ppm slight headache with 2-3 hours
• 400 ppm Headache within 1-2 hours
• 800 ppm Sickness & twitching of limbs within 1-
2 hours; unconsciousness in 2 hours
• 1600 ppm Headache within 20 minutes; death
within 2 hours
• 3200 ppm Death in 30 minutes
• 6400 ppm Death in 10-15 minutes
• 12800 ppm Death in 1-3 minutes
AirTight Building
• Negative pressure conditions in
homes can create back- drafting
of combustion appliances
• Common exhaust equipment (ie
attic fan, bathroom exhaust,
fireplace) can compete with the
normal venting process of
combustion appliances
Graphics © COAD 1996
CO Home Alarms
• UL 2034 Standard Oct. 1, 1998
• Alarm Set Points
70 PPM for 3 hours 9 minutes
150 PPM for 50 minutes
400 PPM for 15 minutes
• No symptoms – call authorized Contractors
• Symptoms – call 911
Why Test…..Combustion Efficiency = Fuel Savings
$56$085%
Efficiencies as
found
$111$59$080%
$167$118$63$075%
$222$176$125$67$070%
$278$235$188$133$71$065%
$333$294$250$200$143$7760%
90%85%80%75%70%65%Efficiency
Readings Improved
to
Environmental Gases (NOx)
• NO + NO2 = NOx (Nitrogen Oxides)
• Environmental gas that contributes to formation of Acid Rain, Ozone and Smog
• EPA Regulates NOx for air pollution
• NOx forms in flue gas
Thermal NOx – Comb air combine with high flame temperature
Fuel NOx – Nitrogen based fuels combine with excess air
Prompt NOx – early, low temperature combustion
What to test: General Testing Advice
• Basic Advice –
Test In (as found) / Test out (as left)
Test from building entry to combustion process for CO
Be prepared for other tests (∆T, ∆P, CO ambient)
Always follow Manufacturer‘s Specifications when available
• Document all work
• Your Instruments
Understand how they work and their limitations
Handle properly
Maintain them
What to test: Ambient CO
• For both you and your customer’s safety!
• Test in the combustion air zone (CAZ) and living spaces
• CO readings should be communicated to the homeowner.
• If at any time during this test ambient CO levels exceed 100 ppm evacuate
occupants and ventilate the dwelling immediately.
• Ventilate room if CO in room air is above 35 ppm
• Be aware of local regulatory limits to comply their set “safe” operating
conditions. If unable to correct, the appliance should be made inoperable.
What to test: Draft Test
• Verifying draft and checking for spillage is an important
safety consideration
• Performed safety inspection for operation (NFPA 54 Annex G)
• Draft should be stable in a steady operating state
• Under NFPA standards, an appliance should prove draft in 5
minutes
NOTE: If appliance and chimney are cold, it could take up to 10
minutes to establish draft.
• For common vented appliances, confirm draft of both
appliance individually and operating together.
This is to verify no spillage of combustion gases in any operating
scenario.
How to test: Heat Exchanger Examination
Measurement Procedure
• 1. Follow the manufacturer's instructions to properly zero the combustion analyzer.
• 2. Insert the combustion analyzer in the appropriate test position in the furnace.
a. For atmospheric draft appliances this would be directly in the heat exchanger cell.
b. For 80+/90+ furnaces this would be in the stack.
• 3. Start the furnace and observe the oxygen reading for stability. (1-3 minutes)
• 4. When the blower starts, watch for a change in the O2 reading. If the blower starts
prior to stabilization of the O2 reading, a piece of cardboard can be inserted and
removed during operation to observe if any changes in the combustion readings
take place.
• Corrective action:
Attempt to visually find the crack or hole.
A. If you can find the defect, show it to the customer.
B. On the service invoice, write that your testing indicates presence of a leak in the
heat exchanger. (Do this even if you cannot find the leak.)
C. Inform the customer, in writing, that the heat exchanger has a defect and poses a
potential danger. (Do this even if you cannot find the leak.)
How to test: Gas fired burners
Measurement Procedure
• 1) Set up the combustion analyzer per manufacturer's instructions.
• 2) Verify combustion analyzer condensate/water trap plug/access is properly
sealed, there is no water in the water trap and thermocouple tip is not touching
side of probe tube.
• 3) In uncontaminated air (outdoor) start the analyzer and allow unit to complete
zeroing process. Never allow the analyzer to zero in the stack unless the
manufacturer's design allows this
• 4) Measurements must be made in each cell of the heat exchanger. If needed a
5/16" hole can be made in the front of the draft diverter to allow measurement access.
• 5) Allow furnace to operate for ten minutes or until stack temperature stabilizes.
• The furnace must establish draft (measured in the flue pipe) with ten minutes of
operation.
• 6) Measure and print combustion results for each cell in the furnace.
• 7) Compare results for each cell
How to test: Gas fired burners
Oxygen : 7 % - 9 %
Carbon Dioxide: 6.5 % - 8 %
Stack Temp : 325 ºF to 500 ºF
Stack Draft: -.02WC to -.04WC
Carbon Monoxide: < 100 ppm
Efficiency: 75-80%
Combustion tests must be taken in each port!
Always follow Manufacturer‘s Specifications
when available!
How to Test: Draft Induced Gas Fired Burners
Measurement Procedure
• 1. Set up the combustion analyzer per manufacturer's instructions.
• 2. Verify combustion analyzer condensate/water trap plug/access is properly
sealed, there is no water in the water trap and thermocouple tip is not touching
side of probe tube.
• 3. In uncontaminated air (outdoor) start the analyzer and allow unit to complete
zeroing process. Never allow the analyzer to zero in the stack unless
manufacturer's design allows this
• 4. Measurements must be made in the vent connector or stack.
• 5. Allow furnace to operate for ten minutes or until stack temperature stabilizes.
The furnace must establish draft (measured in the flue pipe) with ten minutes of
operation. Verify flue gasses are not spilling from the draft hood of the hot
water tank if common vented!!
• 6. Measure and print combustion results prior to and after making any adjustment
to the furnace.
Note: If furnace is multi-stage or modulating, each stage must be checked
independently to assure safe operation through the entire operating range.
How to test: Draft Induced Gas Fired Burners
Oxygen : 7 % - 9 %
Carbon Dioxide: 6.5 % - 8 %
Stack Temp : 325 ºF to 400 ºF
Stack Draft: -.02WC to -.04W
Carbon Monoxide: < 100 ppm
Efficiency: 80-82%
Always follow Manufacturer‘s Specifications
when available!
How to test: High Efficiency Sealed Combustion
Measurement Procedure
• 1. Set up the combustion analyzer per manufacturer's instructions.
• 2. Verify combustion analyzer condensate/water trap plug/access
is properly sealed, there is no water in the water trap and thermocouple
tip is not touching side of probe tube.
• 3. In uncontaminated air (outdoor) start the analyzer and allow unit to
Complete zeroing process. Never allow the analyzer to zero in the
stack unless manufacturer's design allows this
4. Measurements must be made in the PVC flue pipe, and temperature of
combustion air must be properly referenced in the intake pipe
(with an auxiliary temperature probe or other process) to get
accurate combustion efficiency results.
• 5. Allow furnace to operate for ten minutes or until stack temperature stabilizes.
• 7. Measure and print combustion results prior to and after making any adjustment
to the furnace.
Note: If furnace is multi-stage or modulating, each stage must be checked
independently to assure safe operation through the entire operating range.
How to test: High Efficiency Sealed Combustion
Oxygen : 5% - 7 %
Carbon Dioxide: 7 % - 8.5 %
Stack Temp : Less than 125F
Stack Draft: -.02“WC to -.08“WC
Carbon Monoxide: < 100 ppm
Efficiency: 88-92%
Measurements must be made in the PVC flue pipe, and temperature
of combustion air must be properly referenced in the intake pipe
(with an auxiliary temperature probe or other process) to get
accurate combustion efficiency results.
Always follow Manufacturer‘s Specifications when available!
How to test: Gas Fired Power Burners
Measurement Procedure
• 1. Set up the combustion analyzer per manufacturer's instructions.
• 2. Verify combustion analyzer condensate/water trap plug/access
is properly sealed, there is no water in the water trap and
thermocouple tip is not touching side of probe tube.
• 3. In uncontaminated air (outdoor) start the analyzer and allow
unit to complete zeroing process. Never allow the analyzer to
zero in the stack, unless manufacturer's design allows this.
• 4. Measurements must be made in the stack before the barometric damper if
equipped.
• 5. Allow furnace to operate for ten minutes or until stack temperature stabilizes.
The furnace must establish draft (measured in the flue pipe) with ten minutes of
operation.
• 6. Measure and print combustion results prior to and after any adjustments are
made.
How to test: Gas Fired Power Burners
Oxygen: 3.0 % - 6.0 %
Carbon Dioxide: 8.5 % - 11.0 %
Stack Temp (gross): 320 ºF to 570 ºF
Carbon Monoxide: <100 ppm
Draft: -0.02“WC to -0.04“WC Over fire
Draft: Positive pressure (Manufacturer’s specifications)
Always follow Manufacturer‘s Specifications when available!
How to test: Oil Fired Power Burners
Measurement Procedure
• Find a trace of smoke using your smoke tester
• Measure the O2 or CO2 using your combustion analyzer
Measurements must be made in the stack before the barometric
damper if so equipped
• Open air shutter to increase O2 or decrease CO2 by 1%
• Leave at Zero Smoke
Draft
Combustion Gas Analyzers:
• Flue Gas Monitoring
Combustion Efficiency
Boiler/Furnace Safety
Compliance Level Testing (NOx & SO2)
• Ambient CO Testing
• Positive/Negative pressure Testing
Fuel Pressure Tests
Stack Draft Tests
Duct Static Pressure
• Dual Probe Temperature Measurement
Moisture and Particle Protection
© 2005 testo inc, Bill Spohn
• Condensate and water traps
• Empty after each use
• Cleaning
• Maintaining (cracks or damage)
• Changing
• Air tightness
• Particulates and Filters
• Keep clean and dry
• Maintaining
• Change when discoloration
Testing Tips for your Analyzers
• Begin testing at Steady state combustion (warm up boiler)
• Use CO sensors with NOX filters to guarantee best accuracy
• Don’t over range your sensors, use them as designed
• Check water trap and filters on analyzer while sampling
• Maintain recommended calibration and service intervals on
combustion analyzers
O2 sensor is calibrated on start up of analyzer (fresh air environment)
CO, NO, NO2, SO2 sensor needs to be calibrated periodically (1 x
year)
Develop your own calibration protocol if necessary
Wrap-up: Remember
• Combustion testing assures safe and optimized
operation
• Your customer expect this from professionals
• Understanding proper operating parameters and
conditions will help you to diagnose and correct
problems
• Preforming Combustion testing insures the
performance of the system and limits liability
exposure
Testo 310: Fully Featured Residential Analyzer
• O2, CO, Temp (amb & stack), Draft & Pressure
• Efficiency, CO2, Ex Air, CO (amb & air free)
• No Leak, kink-free hose
• 10 hour lithium battery
• Backlit display
• Wireless printing
300 Residential / Commercial kit overview
Replaces testo 320
Why Choose a Testo Combustion Analyzer?
• Does the job right the first time
Testo Analyzers deliver accuracy from the first measurement to the last
- Self-check and on-board diagnostics
Built-in NOX filters standard on our CO sensors
- Eliminates cross sensitivity errors that yield false high CO readings
• Features and accessories to perform more jobs
- Full featured analyzers provide all the measurements you need for
commissioning and troubleshooting
- 30 second start-up
- Fast response from high velocity hoses
- Pre-calibrated, field replaceable sensors
• Built to last for long haul
• Expertise second to none
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