9. Combustion Gas Separation
• Porous Crucible
– Remove ash and tin cap/foil
• Quartz Wool
– Promote conversion of solid
samples to gaseous phase
• Furnace Reagent
– Remove’s Halogens and Halides
• Honeycomb
– Trap large debris
10. Combustion Gas Separation
• Glass Wool/Steel Wool
– Particulate removal
– Corrosive Salts and Acids
• Particle Filter
– Removal of dust
*This tube is empty for the CHN
11. Combustion Gas Separation
• Precooler/T.E. Cooler
– Removal of Moisture, Sulfur
and Oxides
*FP & CN models only
12. Ballast Collection
• Gases are collected in the
ballast
• When Ballast Pressure
reaches Target Pressure,
flows stop and equilibration
begins per the Method
settings
13. Combustion Gas Sampling
• Gases from Ballast released
through aliquot loop
• When ballast pressure drops to a
specified amount, sampling is
complete
• Gases isolated in aliquot loop
• Gases equilibrate for time
specified in method parameters
20. Solid State Infrared Detection
• Reference ~3.0 volts
• Output decreases relative to absorbance in wavelength
• Signal is inverted to become mg/sec. integration
22. Thermal Conductivity Detection
• All gases contain unique
conductive properties
• Thermal conductivity is the
rate at which heat is drawn
from a body
• The amount of heat
removed is proportional to
the concentration of a
selected gas present
•He = 33 cal./sec.
•N2 = 5.6 cal./sec.
•CO2= 3.3 cal./sec.
•SO2= 1.6 cal./sec.
•Ar = 3.8 cal./sec.
•Air = 5.4 cal./sec.
•O2 = 5.7 cal./sec.
24. Thermal Conductivity Detection
• Output increases due to change in thermal conductivity
around measure filament
• Signal converted to mg/sec integration
31. Ballast Target Pressure
• Ballast fill is based on a
calculated target pressure
• Value is calculated using the
Altitude at which the
instrument is located
• This will also change the
leak test pressurization
33. Signal Processing
• An area integration is performed on the signal output from the
detectors
• Correction factor are applied to this raw area to calculate final
results
34. System Blank
Definition - A measurable gas from a source other than the
sample
• Primary sources affecting Nitrogen are N₂ or Ar from Oxygen
supply
• Another source affecting Nitrogen is O₂ if the copper catalyst
is depleted
• Primary sources affecting Carbon and Hydrogen are
hydrocarbons from Oxygen supply
35. Blank Characteristics
• Blank affects entire slope equally
• The blank is an AREA adjustment
• Blank is most apparent at lower end of the slope
Actual Concentration
M
e
a
s
u
r
e
d True Slope
Slope affected
by blank
36. Atmospheric Blank
• Atmospheric blank corrects for trapped air
• Affects Nitrogen only
– Determined by analyzing the following materials:
Atmospheric Blank (Nitrogen only)
Type of material being
analyzed
Suitable Material for
Determining Blank
Leco Part No.
Feed Material ground sucrose 501-441
Flour ground sucrose 501-441
Plant Tissue ground sucrose 501-441
Soil
Com Aid for liquids (baked off
at 1000°C for 10 minutes)
501-427
Coal Graphite 502-634
Coke Graphite 502-634
Liquid samples Distilled Water n/a
**Note: Use the same sample mass as your unknown sample
37. Calibration
• Precision – measure in the
reproducibility or repeatability in
which measurements show the
same result
• Accuracy – degree of closeness
of a quantity to the accepted or
true value
• Blanks & Drifts MUST be precise
• Calibration will correct for
Accuracy, but not precision
Not Accurate
Not Precise
Accurate
Not Precise
Not Accurate
Precise
Accurate
Precise
Precision vs Accuracy
38. Calibration
• Run a standard that will represent the expected content of
the unknown sample
• Run 3-5 standards to obtain a good average
• Calibration sets the ratio of determined area to actual mg
content
• In order to be used to calibrate the instrument, calibration
standards must first be added to the ‘STANDARDS’ list
40. Drift
• Corrects for day to day changes in the system response
• Drift standard MUST BE designated as part of the Calibration
Curve
• At least three values should be used
• Always ensure that adequate blanks and conditioners are run
prior to drift standards
46. Print Report Settings
• Configure the Print Report Format from the following options
• Report Format
– Report with Plots
• Display a report with data plotted
– Tabular Report
• Display data in a table
– Simple Print
• Display a report based on the columns in the spreadsheet
– Group Report
• Data is grouped by name; Average, STD, & RSD printed when
selecting multiple samples
47. Print Report Settings
• Statistics
– None
• No statistics will display
– Report with Plot
• Statistics will display a line plot
– Tabular Report
• Statistics will display a table
• Heading Text
– Title used for the Report
• Define Report Fields
– Fields Tab will be displayed with the Report
• Line Printing & Automatically Print After each Analysis
– A report will print after each Analysis
48. Print Report Settings
• Fields
– Choose the Fields to be displayed for the Report
• Font
– Customize the Font Name, Style, and Size of the text
• Elements
– Specify the following
• Reporting Units
• Plot Color
• Plot Pattern
• Significant Digits
50. Data Transmission
• Transmission Format must be configured to match host
computer
• Set up the Format with the options under the following tabs
– Fields
– Delimiters
– Automation
• * Box must be checked, or data will not be sent automatically
(manual transmission only)
– Communication Settings
– Advanced
– Preview
51. Text Export
• Configure the Text Format
to send sample data to an
external device or a file on
the Computer
• Set up the Format with the
options under the following
tabs
– Filename
– Fields
– Delimiters
– Automation
– Advanced
– Preview
• To Text Export Data Manually
– Highlight the data
– Go to ‘Samples’
– Choose ‘Text Export Data’
– Choose from the Formats
Listed
• Text Export Buffers
– Used to export sample plot
data
• Text Import Data
– Used to import sample data
from a spreadsheet
52. Diagnostics
• Ambient Chart
– View all Temperatures, Pressures, and Voltages of different
components in the instrument
• Solenoids/Switches
– Chart displaying all solenoid locations and their on/off positions
– Interactive screen to toggle valves for troubleshooting
• Leak Check
– Whole O₂
– Segmented O₂
– Whole He
– He Aliquot Loop
53. Diagnostics
• System Check
– A diagnostic test of the major systems in the instrument
• Network Communications
• Solenoids Active
• Solenoids Off
• Pneumatic and Helium Pressures
• Pressure
• Temperature
• IR & TC Cell Values * Instrument Specific
55. Hardware Calibrations
• Set TC Cell Barometric pressure
• Set TC Cell Bridge Voltage
• Set Ballast Target Pressure
• Backup Calibration saves the
following parameter values
– Barometric Pressure Calibration
– Combustion Flow Calibration
– TC Bridge Value
– Furnace Calibrations
– IR Cell Reference and Saturation
Values
56. Network
•Communication is through Ethernet port of PC to System
Host in instrument
•Programmed controllers operate individual areas and report
status to host through Distribution Card
PC
System
System
Host
(Ethernet Card)
Catalyst Heater
Controller
Furnace
Controller
Pneumatic
Manifold
Controller
Up to 3
IR Cells
IR Cell
Controller
System
Distribution
Oven
Controller
TC Cell
Controller
TE Cooler
Controller
(N/CN only)
57. Database Management
• Used to create a new database or retrieve previous data
• Database backup specific to a specified time interval or number of
analysis
• When creating a new database;
– Export Samples, Methods
– Perform Hardware Backup
– Print System Parameters, Standards
– Capture a screen shot of Print Format & Transports
• To access the database
– Close the software
– Select Start in Windows
– Select All Programs
– Select LECO
– Select Instrument
– Select Database Management
58. Database Management
• Add or Select Databases
• Validate a corrupt Database
• Delete old Databases
– Only the connection will be
deleted
– Database will still be stored on the
hard drive
• After creating a new Database
– Software will launch automatically
– Import previously Exported Data
or enter the information manually.
61. Daily Setup
• Inspect gas supply
• Perform an Oxygen and Helium Leak Check
• Inspect/Replace Catalysts, Reagents, Primary Filter, Particle Filter
• Inspect/Clean Load Head
• Check Counters
– Change/Inspect items nearing interval
62. Daily Setup
• Verify Maintenance performed with a Leak Check
• Run Conditioners
– 2-3 analysis of a combustible material (e.g. samples or Standards)
– Conditioner results should be disregarded
• Run Blanks
– Perform blanks until values are low and stable- 0.02 to 0.06% or an
area of less than 10.0 for Nitrogen (0.00 to 0.02% for C and H)
– Set blank daily using a minimum of 3 values
63. Daily Setup
• Perform a minimum of 3 Calibration Check analyses at the
designated Drift level
• If values are outside of the allowable tolerance but maintain
precision, use those to drift the calibration
9.55
9.56
9.59
9.54
9.58
9.53
9.55
9.52
9.50
9.54
9.54
9.59
9.56
9.52
9.55
Good Drift Bad
EDTA with a Certified Value of 9.56 and Standard Deviation of +/- 0.03
65. Reagents
• Lecosorb will change color as it
gets depleted
• Anhydrone will not change
color , but will become ‘Caked’
when depleted
• Incoming Helium Scrubber
– Change every ≈ 2000 samples or
upon inspection
• Aliquot Dose Scrubber
– Change every ≈ 300 samples or
upon inspection
Incoming Helium Scrubber
Aliquot Dose Scrubber
66. Porous Crucible
• Porous Crucible
– Change every ≈ 300 samples for
Foils and ≈ 50-75 samples for
high ash content
– Crucible should not get more
than ¾ full
• Quartz Wool
– Change every ≈ 1500 samples or
when restricted
67. Furnace Reagents
• Quartz Wool
– Change every ≈ 1500 samples or when
restricted
• Furnace Reagent
– Change every ≈ 1500 samples
– 50cc of reagent dried for 2 hrs @ 105°C
prior to packing
• Honeycomb
– Change when visibly dirty
68. Primary Furnace Filter
• Glass Wool/Steel Wool
– Change every ≈ 75 samples or
when visibly dirty
*This tube is empty for the CHN
69. Pre-Cooler
• Clean Oxides from chamber
every 1-2 weeks based on sample
matrix
• Re-lubricate or replace O-rings
• Inside of cooler can be lightly
cleaned with a polishing pad
70. T.E. Cooler
• Clean chamber and ports
every 1-2 weeks
– Cleaning interval based on
sample matrix
– A polishing pad may be useful
to remove build up
• Inspect or replace O-ring
71. Particle Filter
• Particle Filter
– Replace when visibly dirty
– Pay close attention to
orientation of filter when
replacing
72. C-Flex Assembly
• Change every 3-6 months in
conjunction with Ballast
• The assembly as a whole
must be replaced
73. Ballast
• Clean Ballast every 3-6 months
• Disassemble Ballast and wash
parts with warm soapy water
• Rinse with Isopropyl Alcohol
• Replace all O-rings, gaskets
and re-lubricate Ballast
74. Aliquot Dose
• Inspect or clean the Aliquot
Dose Stem every ≈ 750 samples
• Replace and re-grease O-rings if
worn
• Look for irregularities
Press the doser release button
and pull out the doser stem
76. Combustion Tube Replacement
• Cool furnace down to 400°C before turning power off
• Remove loading head and top cover plate
• Remove adapter blocks from top of the tube
78. Combustion Tube Replacement
• Use a rag or towel to handle the new combustion tube
• After tube is replaced and bottom plate is installed tilt
furnace back
• Adjust bottom ramp plate so that the tube extends ¼ inch
above mounting plate and install new O-rings (no grease)
79. Loading Head
• Use Solenoids tab under
Diagnostics to toggle Slide
Block Seal
• Remove Slide block
• Re-lubricate O-ring on
pneumatic seal
81. Maintenance Kits
• Kits include regular maintenance items like O-rings,
combustion tube, filters and c-flex tubing
• Consumable items like reagents and standards are NOT
included
– Part number for FP/CN/CHN is 104-168
– Part number for 628 with Sulfur Add-On is 104-163
89. Segmented O₂
• Be aware that it is possible to have a “Whole O₂” leak check fail
while all segmented checks pass
• In this case check PV3 and the c-flex tubing in the area
highlighted below
92. Helium Leak Isolation
If Doser Fill check fails but Doser
Dump passes, check the small bypass
loop between doser ports “A” and “H”
If Doser Fill check passes but Doser
Dump fails, check the aliquot loop and
its connections at ports “C” and “F”
93. Combustion Flow Restrictions
• Restrictions increase combustion pressure
• Restrictions slow down gas flow
• Symptoms: Blanks stabilize samples do not
• Observe combustion pressure in Ambient Chart
94. Combustion Flow Restrictions
• Remove Primary Filter
• Start an analysis at Medium
flow
• If combustion pressure > 5
psi and oxygen flow is lower
than selected profile,
repack combustion tube
Particulate buildup
95. Combustion Flow Restrictions
• If pressure is ≈ 3 to 4 psi, re-
install filter and remove
inlet to precooler
• If pressure is > 5 psi, clean
filter tube, gas outlet line
and block ports
• CHN remove the inlet line
to ballast
96. Combustion Flow Restrictions
• If pressure is ≈ 3 to 4 psi,
replace precooler inlet and
remove outlet of precooler
• If pressure is > 5 psi, clean
precooler
97. Combustion Flow Restrictions
• If pressure is ≈ 3 to 4 psi,
replace precooler outlet
and remove Particle Filter
• If pressure is > 5 psi, clean
Thermoelectric cooler
99. Hardware Failures
• Failures within the instrument will be displayed in the bottom
left corner
• Go to → Maintenance → View Log File to view past errors and
other changes that were made and recorded in the software
100. Hardware Failures
• Symptom
– Primary or Secondary Temperature reads 20°C
• Solution
– Defective Thermocouple
• 628 only has 1 Primary Thermocouple and 1 Secondary
Thermocouple
101. Thermocouple Replacement
• Remove loading
head and cover
plate to release
furnace door
• Remove the inlet
and outlet adapter
blocks
102. Thermocouple Replacement
• Release latch and
pull the furnace
forward until the
pivot lines up with
the side slots then
lift the furnace out
Latch
Pivot
105. Furnace Failures
• Check temperature in Ambient Monitor
• If temperature indication is a low temperature, observe
temperature of the opposite furnace
• If the opposite temperature is also low, close program, turn
off instrument power.
• Turn instrument back on and reopen program
• Make sure temperature stops at set point
Symptom- Low Heat
106. Furnace Failures
• Observe the lights on the
furnace control card
• If the lights stop blinking
when the furnace reaches
its set point but the furnace
continues to heat the
control card is defective
107. Furnace Failures
• If the control lights are
blinking and the furnace is
not heating check the fuses
on the control card
108. Furnace Failures
• If the fuses are good check
the heating element
connections
• INSTRUMENT MUST BE
POWERED DOWN OR HAVE
THE HEATERS DISABLED IN
THE FURNACE TAB UNDER
DIAGNOSTICS
1
Secondary Furnace
Primary Furnace
109. Furnace Heating Elements
• If connections are tight,
– Disconnect element leads
from terminal block
– Check resistance of each
element
110. Furnace Heating Elements
• Remove the load head and
top cover
• Remove inlet and outlet
adaptor blocks
• Remove furnace duct and
front bracket
• Remove combustion tube
• After leads are
disconnected, remove
defective element
111. Carousel Plate
• Remove 4 screws
on bottom of
Carousel
• Remove and
clean plate with
alcohol
• Apply a thin coat of
Lubriplate bearing
grease, 769-434
112. Slide Block Movement
• Access Solenoid Screen of Diagnostics
• Toggle Slide Block Seal then toggle Slide Block Open/Close
Solenoid and observe movement
• Adjust speed for smooth movement
• Speed must be adjusted if using more than 1 carousel
Extend Speed Adjust
Retract Speed Adjust
113. For More Information
Contact LECO at:
World Headquarters/United States
In United States: 800-292-6141 or 269-985-5496
Outside U.S.A.: 269-983-5531
Email: info@leco.com
www.leco.com
