Lattner Low-NOx Boiler Information - Lattner Boiler Company

LATTNER BOILER COMPANY
Low-NOx Boilers
Lattner HE Model
3 HP to 9.5 HP
SCAQMD-Approved for California & Texas
Less than 30 ppm NOx (corrected 3% O2)
Lattner burner (see figure 3)
Pre-mix combustion gas technology
Improved efficiency
Tubeless; Very low maintenance
Small footprint
Large hand holes for easy inspection and
cleanout
Lattner WLF Model
9.5 HP to 50 HP
SCAQMD-Approved for California & Texas
Less than 30 ppm NOx (corrected 3% O2)
Webster power burner (see figure 4)
Flue gas re-circulation technology
Four pass gas travel
Improved efficiency
Tubeless; Very low maintenance
Removable panels for pressure vessel
access
Lattner Boiler Company
1411 9 th St. SW
Cedar Rapids, IA 52404
T: (319) 366-0778
F: (319) 366-0770
W: www.lattner.com

LATTNER BOILER COMPANY
Low-NOx Boilers
Basic Instructions for Start-Up of Lattner Low-NOx Boilers
The burner system of the Lattner low-NOx boiler consists of a gas valve with built-in pressure
regulator, motor driven blower, pre-mix burner tubes and electronic ignition and flame monitoring.
The system is basically similar to any boiler with a forced draft power burner and must be started in
a similar fashion to any boiler with this type burner.
In order to properly start the burner you will need the following items:
1. Combustion analyzer
2. Stop watch
3. Calculator
4. Knowledge of the BTU content of the fuel gas.
5. Method of measuring the fuel gas input in cubic feet per hour.
6. Formula for calculating BTU input to the burner
7. Formula for calculating NOx corrected to 3%. The maximum is 30 ppm.
8. CO2 / O2 / Excess Air ratio curve chart
9. Carbon monoxide tester
10. “U” tube manometer or aneroid gas pressure gauge
Before attempting to actually start the boiler, check the function of the low water cutoffs and
pressure controls. The gas piping must be properly purged up to the point of connection to the gas
train. It is necessary to make sure the voltage to the boiler is correct.
The boiler should then be started with the fuel gas shut off to make sure no valves will open during
the burner pre-purge cycle. After this check is confirmed, the gas valve to the burner train can be
opened and the burner started.
It is absolutely necessary to determine the firing rate of the boiler by actually determining the
volume of fuel gas supplied to the boiler. Using a stop-watch and reading the fuel gas volume in
cubic feet for a specific period of time at the gas meter, the actual volume of gas in cubic feet per
hour is calculated using the formula for calculating the BTU input to the burner. Further calculation
using the actual BTU per cubic foot of gas, the exact firing rate can be determined. (Contact the
gas utility supplier to determine the BTU per cubic foot content of the fuel gas). Adjust the fuel gas
pressure regulator on the combination gas valve until the BTU input matches the BTU input rating
of the boiler. As the fuel gas input is changed, readjustment of the air shutter will be required to
prevent the loss of burner flame.
Use the combustion analyzer probe to sample the flue gas below any draft regulator (if used). In
general, the 02 reading obtained on the combustion analyzer may be around 4% or slightly higher.
Adjust the air shutter on the burner blower to change the readings. As air shutter adjustments are
Lattner Boiler Company
1411 9 th St. SW
Cedar Rapids, IA 52404
T: (319) 366-0778
F: (319) 366-0770
W: www.lattner.com

LATTNER BOILER COMPANY
Low-NOx Boilers
made, the fuel gas pressure regulator will require minor adjustments to maintain the correct fuel
gas BTU input to the burner. Any pressure regulator readjustment may also require minor changes
in the air shutter adjustment.
Adjust the air shutter while observing the NOx readings on the analyzer. Adjust the air shutter to
obtain low NOx readings. The finalized burner adjustments are those that will produce the lowest
corrected NOx readings using the formula for calculating NOx corrected to 3% calculation. Boiler is
SCAQMD certified for 30 ppm NOx.
Check the flue gas content for carbon monoxide. The reading must be below 400 parts per million
but preferably around 40 parts per million.
The “U” tube manometer or aneroid gas pressure gauge is used only to observe any changes in the
manifold gas pressure as adjustments are being made. After any adjustments are finalized, record
these readings for future use. These readings will probably be about 2 Inches water column
pressure.
Formula for calculating NOx corrected to 3% 02:
Corrected value =
17.95
20.95 - 02%
x ppm NOx
Lattner Boiler Company
1411 9 th St. SW
Cedar Rapids, IA 52404
T: (319) 366-0778
F: (319) 366-0770
W: www.lattner.com

LATTNER BOILER COMPANY
Low-NOx Boilers
Gas Input Determination by Gas Meter Measurement
The gas input to a burner should be determined by “clocking” the gas meter. Failure to apply meter
correction factors can lead to over firing which could result in boiler damage or an unsafe operating
condition.
When determining gas flows using a gas meter, several factors must be considered to obtain an
accurate measurement. The inlet gas pressure and temperature to the meter must be determined
and the inlet gas pressure and temperature that was used to calibrate the gas meter must be
known.
The calibration pressure (commonly referred to as base pressure) and temperature may be marked
on the meter dial or nameplate. If this information is not on the meter then use 4 oz (7 iwc) as
base pressure and 60°F as the calibration pressure and temperature.
The formula for calculating the gas flow is as follows:
Cu. Ft. x 3600 x Press. Corr. x Temp. Corr.
CFH =
Time
CFH – Cubic feet per hour
Cu. Ft. – Cubic feet of gas clocked
3600 – number of seconds in one hour
Press. Corr. – Correction factor for inlet gas pressure different than base pressure (see figure 1)
Temp. Corr. – Correction factor for inlet gas temperature different than calibration temperature
(see figure 1)
Time – Time in seconds required to measure Cu. Ft.
Example:
For example, assume the meter is calibrated with a base pressure of 4 oz and temperature of 60°F
and you measure the inlet pressure to the meter as 5 psi with a gas temperature of 70°F. You
determine it takes 42 seconds for 50 cu. ft. of gas to flow through the meter. For 5 psi, the
pressure correction factor is 1.324 and for the 70°F the temperature correction factor is .981. The
calculation is:
CFH =
50 x 3600 x 1.324 x .981
42
CFH = 5566 cubic feet per hour gas flow
Lattner Boiler Company
1411 9 th St. SW
Cedar Rapids, IA 52404
T: (319) 366-0778
F: (319) 366-0770
W: www.lattner.com

LATTNER BOILER COMPANY
Low-NOx Boilers
For heat input to the boiler, the CFH gas flow must be multiplied by the BTU content of the gas.
Typically, the BTU content for natural gas is 1000 BTUs per cubic foot of gas and this number can
be used if the actual number is not known. In the above example, if the BTU content of the gas is
1050 BTUs per cubic foot, then the heat input would be:
Heat Input = CFH x BTU per Cu. Ft. = 5566 x 1050 = 5,844,300 BTUs per Hour
Lattner Boiler Company
1411 9 th St. SW
Cedar Rapids, IA 52404
T: (319) 366-0778
F: (319) 366-0770
W: www.lattner.com

LATTNER BOILER COMPANY
Low-NOx Boilers
Figure 1
Lattner Boiler Company
1411 9 th St. SW
Cedar Rapids, IA 52404
T: (319) 366-0778
F: (319) 366-0770
W: www.lattner.com

LATTNER BOILER COMPANY
Low-NOx Boilers
Figure 2
Lattner Boiler Company
1411 9 th St. SW
Cedar Rapids, IA 52404
T: (319) 366-0778
F: (319) 366-0770
W: www.lattner.com

LATTNER BOILER COMPANY
Low-NOx Boilers
Figure 3
Lattner Boiler Company
1411 9 th St. SW
Cedar Rapids, IA 52404
T: (319) 366-0778
F: (319) 366-0770
W: www.lattner.com

LATTNER BOILER COMPANY
Low-NOx Boilers
Figure 4
Lattner Boiler Company
1411 9 th St. SW
Cedar Rapids, IA 52404
T: (319) 366-0778
F: (319) 366-0770
W: www.lattner.com