Enertech Bentone BFG1 Technical specifications

Providing sustainable energy solutions worldwide
178 088 35-4 2018-03-13
Installation- and maintenance instruction
BFG1
2-stage

3Bentone BFG1
General
Table of contents
GENERAL
1. General Information_______________________________________________________4
Safety instructions ______________________________________________________4
Actions to take if you smell gas____________________________________5
Burner servicing schedule ___________________________________________6
Component replacement intervals________________________________6
Delivery check____________________________________________________________6
2. Technical data _______________________________________________________________7
2.1 Burners are intended for use at:_________________________________7
2.2 Dimensions _____________________________________________________________7
1.0.1 Dimensions flanges________________________________________7
2.3 Capacity range BFG1 H3 __________________________________________8
2.3.1 Gas categories, approved gases_____________________9
2.3.2 Electric Specification EN 60335-2-102 ____________9
2.4 Model BFG1-2 H3__________________________________________________ 10
2.4.1 Burner output/ Basic settings_______________________ 10
2.5 Description ____________________________________________________________11
2.5.1 Components_______________________________________________12
3. Installation __________________________________________________________________ 13
3.1 Skeleton diagrams _________________________________________________ 13
3.2 Delivery check _______________________________________________________ 14
3.3 Preparations for installation_____________________________________14
3.4 Gas supply ____________________________________________________________14
3.5 Electric connection_________________________________________________ 14
3.6 Setting brake plate and air flow________________________________ 14
3.7 Burner installation___________________________________________________ 15
3.7.1 Hole pattern________________________________________________ 15
3.7.2 Burner installation________________________________________ 15
3.7.3 Gas connections _________________________________________15
3.7.4 Electric connection ______________________________________15
3.8 Control measures___________________________________________________ 16
3.8.1 Gas quality _________________________________________________16
3.8.2 Bleeding_____________________________________________________16
3.8.3 Function test_______________________________________________16
3.8.4 Leakage testing___________________________________________ 16
3.9 Recommended excess air when using default setting 17
3.10 Determining the gas quantity for the system______________17
3.10.1 Example of how to calculate the gas quantity
(natural gas G20): _____________________________________________18
3.11 Calculating the quantity of gas supplied____________________19
3.11.1 Nozzle assembly adjustment ________________________20
3.11.2 Air intake adjustment ___________________________________20
3.11.3 Procedure for setting the amount of air __________ 20
3.11.4 Inlet cone, air control ___________________________________21
3.11.5 Rotation of the air intake ______________________________ 21
3.11.6 Air duct ______________________________________________________ 21
4. Burner Service ____________________________________________________________ 22
4.1 Service__________________________________________________________________ 22
4.1.1 Combustion device service___________________________ 22
4.1.2 Fan motor replacement________________________________23
4.1.3 Air intake and inlet cone service ____________________24
4.1.4 Fan wheel check _________________________________________ 25
4.1.4.1 Inspection ______________________________________________25
4.1.5 Fan wheel service________________________________________ 25
4.1.6 Electrical package _______________________________________26
4.1.6.1 Complete electrical package replacement _____________26
4.1.6.2 Single electrical package component replacement ____27
4.1.6.3 Replacing the damper motor___________________________ 27
4.2 Multiblock MB-ZRDLE 405-412_______________________________ 28
4.2.1 Pressure taps______________________________________________ 30
4.2.2 Electrical connection____________________________________30
5. General instructions ____________________________________________________31
5.1 Flame monitoring and ionisation current check __________31
5.1.1 Flame monitoring ionisation __________________________ 31
5.1.2 UV –detector (QRC)_____________________________________31
5.1.3 Flame monitoring UV-detector (QRC)_____________31
5.1.4 Setting of air pressure switch________________________32
5.1.5 Setting gas pressure switch min____________________ 33
5.1.6 Setting gas pressure switch max___________________33
5.1.7 Handing over of the installation _____________________34
6. Electric equipment LME...____________________________________________ 35
6.1 Wiring diagram ______________________________________________________35
6.1.1 List of components______________________________________36
6.1.2 Function LME...___________________________________________36
6.2 Control program at faults; fault mode indicator LME .... _
37
6.2.1 Colour codes ______________________________________________37
6.2.1.1 Diagnosing alarm causes_______________________________37
6.2.1.2 Limiting of starting repetitions __________________________37
6.2.1.3 Alarm code table _______________________________________38
6.2.1.4 Interface diagnostics ___________________________________38
7. Troubleshooting __________________________________________________________ 39
Gas Burner______________________________________________________________ 39
8. DECLARATION OF CONFORMITY _______________________________42
9. General instructions for gasburners_____________________________43
9.2.1 Installation __________________________________________________43
9.2.2 Maintenance_______________________________________________ 43
9.2.3 If the burner has stopped _____________________________ 43
9.2.4 Shut-Off _____________________________________________________43
9.2.5 Warning______________________________________________________ 43

4Bentone
1. General Information
This Installation and Maintenance manual:
• is to be regarded as part of the burner and must always be kept near
the installation site
• is intended for use by authorised personnel
• must be read prior to installation
• must be observed by all who work with the burner and associated
system components
• work with the burner may only be carried out by certified installers/
personnel
Enertech AB is not liable for any typographical errors and reserves the right
to make design changes without prior notice.
Safety instructions
• The burner may only be used for its intended purpose in accordance
with the product’s technical data.
• The burner may only be installed and operated by authorised
personnel.
• The product is packaged to prevent damage from occurring during
handling. Handle the product with care. Lifting equipment must be
used to lift larger packages.
• The products must be transported/stored on a level surface in a dry
environment, max. 80% relative humidity, no condensation.
Temperature -20 to +60 °C.
• Check that the burner is compatible with the boiler’s output range.
• All components must be installed without being bent, twisted or
subjected to mechanical or thermal forces which can affect the
components.
• The burner must be installed so that it complies with local regulations
for fire safety, electrical safety, and fuel distribution.
• The gas outlet from the pressure regulator shall be configured in
accordance with applicable regulations and lead to a safe area.
• Make sure when installing the equipment that there is enough space to
service the burner.
• Permitted temperature during operation -10 to +60 °C. Max 80%
relative humidity, no condensation.
• The installer must ensure that the room has adequate air supply.
• The room must comply with local regulations pertaining to its intended
use.
• The installation site must be free of chemicals.
• Burner pipes, fan wheels and air dampers may contain sharp edges.
• The surface temperature of the burner’s components can exceed 60
°C.
• Caution: The burner has moving parts, and there is risk of crushing
injuries.
172 515 01 2018-01-02

5Bentone
• The electrical installation must be professionally carried out in
accordance with applicable high voltage regulations, as per Enertech’s
recommendations.
• Before servicing, shut off the fuel supply and turn off the power to the
burner.
• Seal inspections must be performed during installation and servicing to
prevent gas leakage.
• Care should be taken by the installer to ensure that no electrical cables
or fuel lines are crushed or otherwise damaged during installation or
servicing.
• If the boiler is equipped with an access hatch, this must be equipped
with a hatch opening switch connected to the burner's safety system.
• When in operation, the burner’s noise level can exceed 85 dBA.
Use hearing protection.
• The burner must not be put into operation without proper safety and
protection devices.
• A Class BE fire extinguisher is recommended.
• It is forbidden to alter thedesign or use accessories which have not
been approved by Enertech in writing.
• Prior to operation, the following points must be checked:
-fitting and installation work has been completed and approved
-electrical installation has been correctly performed
-flue gas ducts and combustion air ducts are not blocked
-all actuators and control and safety devices are in working order and
correctly set
Actions to take if you smell gas
Turn off the equipment and the boiler. Open windows and doors. Prevent
open flames or sparking, e.g. do not turn lights on or off, do not use any
electrical appliances, do not use mobile phones. Open windows and doors.
Close the gas ball valve. Warn residents; do not use doorbells. Evacuate
the building. Notify the installer or gas supplier once the building has been
evacuated.
172 515 01 2018-01-02

6Bentone
Control system 10 years 250,000 starts
Valve control system 10 years 250,000 starts
Pressure switch 10 years 250,000 starts
Ignition system with flame guard 10 years 250,000 starts
UV flame sensor 10000 hrs N/A
Gas pressure regulators 15 years N/A
Gas valve without seal testing 10 years 250,000 starts
Gas valve with seal testing Replacement upon fault detection N/A
Gas pressure switch 10 years 250,000 starts
Safety blow-off system 10 years N/A
Damper motor N/A 500,000 starts
Contactor 10 years 500,000 starts
Burner 1 year 3000 hrs
Inspection of electrical installation 1 year 3000 hrs
Leakage check 1 year 3000 hrs
Filter 1 year replacement at ∆p>10 mbar 3000 hrs replacement at ∆p>10
mbar
Electrodes Replacement/Cleaning 1 year Replacement/Cleaning 3000 hrs
Brake disc Replacement/Cleaning 1 year Replacement/Cleaning 3000 hrs
Motor 1 year 3000 hrs
Fan wheel 1 Year
Replacement when cleaning
needed/ imbalance
3000 h
Replacement when cleaning
needed/ imbalance
The burner and its components must be recycled according to applicable regulations.
Burner servicing schedule
Servicing must be carried out once a year or after 3000 hours of operation
Component replacement intervals
Delivery check
• Make sure everything is delivered and the goods have not been
damaged during transit.
• If something is wrong with a delivery, report it to the supplier.
• Transport damage must be reported to the shipping company.
172 515 01 2018-01-02

7Bentone BFG1
145
109,5
10
23,5
145
290 195
186 35 272
B
A
The above-mentioned measurements are maximum measurements. They can vary, depending on which components
are used.
1.0.1 Dimensions flanges
Flange 3
BFG1 H3
2. Technical data
2.1 Burners are intended for use at:
• Hot water boilers in intermittent operation
2.2 Dimensions
• Gas connection ¾-1¼”

8Bentone BFG1
Capacity Gas quantity
at min. power
Nm3/h 1)
Gas quantity
at max. power
Nm3/h 1)
BFG1 H3 25 - 100 kW
G 20 2,65 10,58
G 25 3,10 12,41
G 30 0,75 3,10
G 31 1,02 4,09
MB-Bloc Max. connection
pressure mbar
Min connection
pressure mbar
GB-LD 055 65 25
MBC 65 200 25
MBC 120 360 20
MB 403 200 20
MB 405 360 20
MB 407 360 20
kWh/Nm3MJ/Nm3kcal/Nm3
G20 9.5 34.02 8126
G25 8.2 29.25 6986
G31 24.6 88.00 21019
G30 32.5 116.09 27728
Lower heat value Hu at normal state 15°C and 1013.25 mbar EN676
Grade of gas
Natural gas
Natural gas
Propane
Butane
Gas quantity and capacity vary according to grade of gas and connection
pressure.
2.3 Capacity range BFG1 H3

9Bentone BFG1
Measurements according to EN 3746: 2010
Alt.1 The sound level of the burner can be reduced by equipping the burner
with silencer. Installation must be done so it does not prevent air supply
to the burner.
Alt.2 The burner’s noise level can be reduced by connecting the burner’s air
intake to the air duct that opens into an appropriate location. Installation
must be done so it does not prevent air supply to the burner.
2.3.1 Gas categories, approved gases
Only dry gas is permitted for use
Gerätekategorien
appliance categories
Versorgungsdrücke
supply pressures
Bestimmungsländer
countries of destination
Bermerkungen
remarks
II2H3B/P 20:30/360 mbar AT,CH,CZ,DK,EE,FI,GR,HU
IS,IT,LT,NO,SE,SK,SI,TR
II2E3B/P 20:30/360 mbar LU,PL
II2H3P 20:30/360 mbar ES,GB,IE,PT
II2ELL3B/P 20:25:30/360 mbar DE
II2Er3P 25:30/360 mbar FR
II2L3B/P 25:30/360 mbar NL
II2E(R)I3P 20:30/360 mbar BE
I3B/P 30/360 mbar CY,MT
II2R3R 20:30/360 mbar FOR ALL OTHER COUNTRIES
Burner correspond to IP20
2.3.2 Electric Specification EN 60335-2-102
Type BFG1
Motor 110W 0,9A 230V 50Hz 4µF
The recommended main fuse
motor 6,3 A
Control power 1N230V 0,8A 50Hz IP 20
Sound 79 dBA ± 0,5 dBA

10 Bentone BFG1
!Scale value valid at 0 mbar in furnace pressure.
29,0-31,0
16,0-17,0
ø103
2,5-3,5
7,5-8,5
Pressure in the furnace mbar
Burner output kW
-0,5
0,0
0,5
1,0
1,5
2,0
2,5
3,0
3,5
4,0
4,5
5,0
5,5
20 30 40 50 60 70 80 90 100
Burner output kW
0,0
2,0
4,0
6,0
8,0
10,0
12,0
14,0
16,0
18,0
20,0
22,0
25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
Nozzle assembly setting
Scale
Stage 1
Stage 2
2.4 Model BFG1-2 H3
Blast tube length
mm
Blast tube
Dimension A mm
Flange
Dimension B ø
145 121,5 103
245 221,5 103
The above-mentioned measurements are maximum measurements. They
can vary, depending on which components are used.
2.4.1 Burner output/ Basic settings
25 - 100 kW
!Do not exceed working
field

11Bentone BFG1
6
45
10
8
13
15
14
1
2
3
7
11
12
9
13
12
27
11
1
30
29
28
27 26 25
24
23
22
21
20
19
18
17
9
16
8
7
6
2.5 Description

12 Bentone BFG1
32
34
33
31
35
2.5.1 Components
1. Multiblock
2. Adjustment gas valve, first stage
3. Adjustment gas valve, second stage
4. Protective cover start gas adjustment
5. Adjustment regulator pressure
6. Electrical contact, Multiblock
7. Electrical contact, gas pressure switch S9
8. Gas pressure switch
9. Connection multiblock
10. Ignition transformer
11. Gas burner control
12. Electrical contact, X3 (see wiring diagram)
13. Motor
14. Capacitor
15. Blast tube
16. Measuring point regulator pressure
17. Electrical contact, damper motor M2 (see wiring diagram)
18. Damper motor
19. Air regulator, first stage
20. Screw lock adjustment, first stage
21. Electrical contact, second stage X5 och X6 (see wiring diagram)
22. Air regulator, second stage
23. Air pressure switch
24. Measuring point for the air pressure switch on the low-pressure side
25. Air flow indicator (indicates the air setting)
26. Air intake
27. Reset button
28. Nozzle assembly adjustment
under cover plate
29. Cover plate
30. Screw for division of burner
in front and rear part
31. Nozzle assembly
32. Brake plate
33. Ignition electrode
34. Ionisation electrode
35. Nozzle

13Bentone BFG1
Incorporated in the multiblock
3. Installation
3.1 Skeleton diagrams
1. Ball valve
2. Filter
3. Pressure regulator
4. Outlet for gas pressure measuring
5a. Gas pressure switch, min.
5b. Gas pressure switch, max.
6a. Main valve
6b. Safety valve
1)7. Leakage control
9. Air pressure switch
10. Gas burner control
Pos. 5b: Components not required acc. to EN 676.
1)Required above 1200 kW acc. to EN 676.

14 Bentone BFG1
3.2 Delivery check
Check that all has been delivered and that the goods have not been
damaged during transport. If that is not the case, please notify the delivery
company. Transport damages should be reported to the forwarding agency.
3.3 Preparations for installation
Check that the measurements and capacity range of the burner are
compatible with the boiler. The power ratings on the type plate refer to the
min. and max. power of the burner.
3.4 Gas supply
For good operating safety, it is important that the gas supply system is
installed correctly.
Consider the following:
1. Check that the burner is approved for the gas quality of the installation.
If not, please contact the supplier.
2. Check that the gas components of the burner are approved for
indicated gas pressure.
3. The gas supply system should be installed in accordance with current
standards.
4. Pipe lines should be run so that service on boiler and burner is
facilitated.
5. Pipe lines should be run so that eventual contaminants cannot come
into contact with the gas components.
3.5 Electric connection
Before starting the electric installation, the main switch must be turned off.
If the boiler has a 7-pole and a 4-pole Eurostecker connector, these usually
fit directly to the burner. If not, use the connectors included.
(Refer to connection under Electric equipment)
3.6 Setting brake plate and air flow
Before the placing into service, the burner should be initially set according to
diagram.
(Refer to Basic settings). Note that it is only a question of a basic setting
which should be adjusted once the burner has been started.
!If an electric connection other than the one recommended by Enertech is used, a risk of damage and
injury can arise.

15Bentone BFG1
E
F
X1
X2
3.7 Burner installation
3.7.1 Hole pattern
Check that the hole pattern on the boiler matches that of the flange.
(Refer to Technical data.)
3.7.2 Burner installation
1. Install the flange with gasket on the boiler.
2. Insulate between the blast tube and the boiler door to minimize heat
radiation.
3. Check the ignition electrode and ionisation electrode.
(Refer to Technical data).
4. Install the burner on the boiler and lock into the flange (E).
5. Install the gas line on the burner. Check that the O-ring has not been
damaged during installation, fasten with the screws (F).
6. Where support for the multiblock is included, this should be installed.
3.7.3 Gas connections
1. Check the gas pipe dimensions. (According to local regulations).
2. Connect the gas pipe to the gas flange of the multiblock.
3. A manual gas valve should be installed in the vicinity of the burner.
4. No mechanical stresses/forces should exist in the gas connection.
5. Check the sealing of the gas connections, including the multiblock and
flanges.
NOTE!
If the gas connection is via a hose, the support for the multiblock that is
supplied with the burner should be mounted (F). Install the support so that
the underneath of the multiblock rests on it.
3.7.4 Electric connection
If the boiler does not have a pre-wired connector, connect in the included
connector, X2 according to the wiring diagram.
1. Turn off the main switch.
2. Connect the Eurostecker X2 acc. to Alt. 1 - 3 (Refer to Electric equipment).
3. Install the Eurostecker X2 on the burner.
4. Turn on the main switch.

16 Bentone BFG1
3.8 Control measures
3.8.1 Gas quality
Check that the combustion head is intended for the gas quality to be used
(refer to Technical data).
3.8.2 Bleeding
Bleeding of the gas pipe can be achieved by removing the screw on the test
nipple for the inlet pressure. Connect a plastic hose and lead out the gas into
nature. When the bleeding in completed,
don’t forget to install the screw in the test nipple again.
3.8.3 Function test
The electric function test can be done as follows:
When connecting to the mains, check that the phase and zero are not
switched. The gas tap should be closed. To prevent the gas pressure switch
from blocking, it should be bridged temporarily.
After the main switch has been turned on and the max. and control
thermostats have been set, the prepurging period lasts for 30-35 secs. After
this, the pre-ignition is started (0.5-2.5 secs. depending on the design of
the gas burner control). The ignition spark should then be able to operate
faultlessly at the required quantity of air for combustion. The gas valve is
energized and opens. After the end of the safety period (2-3 secs.), the gas
burner control blocks.
The solenoid valve and motor become de-energized. Remove the bridge
after completed testing.
Check that no safety functions are disconnected before placing the burner
into service.
3.8.4 Leakage testing
When leakage testing the gas fittings with test points between the valves, the
solenoid valve should be closed. A pressure gauge should be connected to
the test nipple Pa. The test pressure in the fittings should be 1.5 x max inlet
pressure or min. 150 mbar. If leakage is observed when measuring, localise
the leaking site with soapy water or leak detection spray. After sealing, leak
test the fittings again. After completed trimming, all joints, branching points
and outlets on the gas line should be tested for leaks.

17Bentone
Lower heat value Hu at normal state 15°C and 1013.25 mbar EN676
Grade of gas kWh/Nm3MJ/Nm3kcal/Nm3
Natural gas G20 9.5 34.02 8126
Natural gas G25 8.2 29.25 6986
Propane G31 24.6 88.00 21019
Butane G30 32.5 116.09 27728
3.9 Recommended excess air when
using default setting
Grade of gas Excess air flue gases Max. % CO2
% O2% CO2Lambda 1.2
Natural gas 3–5 ≈10 11.9
Propane 3–5 ≈11.5 13.9
Butane 3–5 ≈11,5 14,1
Liquefied petroleum
gas (LPG)
3–5 ≈11 13,8
3.10 Determining the gas quantity for
the system
The heat values indicated are normal values; the heat value varies according
to the origin of the gas. For more exact information on values, contact the
gas distributor.
172 515 27 2018-01-11

18 Bentone
T = Temperature of gas at the gas meter [°C]
B = Barometer reading [mbar]
P = Pressure of gas at the gas meter [mbar]
f = Factor calculated for multiplication with flow in Nm3/h to
arrive at actual flow in Nm3/h.
V = Actual flow [m3/h]
f = 273 ·B+P
273+T 1013.25
Example A
V0A
= Q .3600 =50 · 3600 ≈ 5.9 Nm3/h
Hu· η34020 · 0.90
Example B
V0B
= Q ≈50 ≈ 5.8 Nm3/h
Hu· η9.5 · 0.90
Example C
V 0C
=Q=50 ≈ 5.9 Nm3/h
Hu· 0,00116 · η8126 · 0.00116 · 0.90
If the barometer reading (altitude), pressure and temperature of the gas
deviate significantly from normal values, this must be taken into account as
follows:
Calculation example:
Q = 50 kW
HU= Example A: 34020 MJ/Nm3
Example B: 9.5 kWh/Nm3
Example C: 8126 kcal/Nm3
η = 90%
V0= Desired quantity of gas [Nm3/h]
Q = Boiler output [kW]
HU= Gas heat value [kWh/Nm3] or [MJ/Nm3] or [kcal/
Nm3]
η=Boiler efficiency [%]
3.10.1 Example of how to calculate the gas quantity
(natural gas G20):
172 515 27 2018-01-11

19Bentone
M = 100 = 0.1 m3
1000
t = 1 + 10 = 0.0194 h
60 3600
V = M = 0,1 ≈ 5.1 m3/h
t 0.0194
Calculation example:
t = 1 min 10 s
M = 100 dm3(litre)
V = M [m3/h]
t
3.11 Calculating the quantity of gas
supplied
The quantity of gas supplied can be calculated if the system is equipped with
a gas flow meter of some type. The procedure here is usually to measure
how long it takes for the burner to consume a certain quantity of gas.
To measure:
t = Time for a certain quantity of gas consumed by the burner. [h]
M = Quantity of gas consumed. [m3]
V = Actual gas flow [m3/h]
V = V0. f
VA= V0A . f = 5.9 . 0.90 ≈ 5.2 m3/h
VB=V0B . f = 5.8 . 0.90 ≈ 5.2 m3/h
VC=V0C . f = 5.9 . 0.90 ≈ 5.3 m3/h
This means that the quantity of gas read from the gas meter should actually
be read off as 1.11 . the calculated flow in a normal state.
f = 273 .945+15 ≈ 0.90 Nm3/h
273+15 1013.25
Calculation example:
T = 15°C
B = 945 mbar
P = 15 mbar
172 515 27 2018-01-11

20 Bentone BFG1
Z
Y
3.11.1 Nozzle assembly adjustment
The burner is equipped with a control which changes the position of the brake
plate in the blast tube. This is used to set the correct pressure differential across
the combustion device and thereby get a good combustion without pulsations.
The setting to be used depends on the set effect and the overpressure in the
boiler. (For basic setting, see Technical data).
Setting brake plate
H3
• Smaller gap: turn the screw to the right
• Larger gap: turn the screw to the left
The setting of the brake plate position affects the air flow. Therefore, the air
must always be readjusted with the air regulation device of the burner.
3.11.2 Air intake adjustment
For two-stage burners, the amount of air is set in two different positions.
When performing adjustments, the maximum load must always be adjusted
first. This is because adjusting the air damper for the maximum load may
affect the air quantity for the minimum load. The maximum load is adjusted
by turning the air regulator (Y). The air setting at maximum load will then
operate so that when the boiler is calling for the maximum load, the damper
motor opens completely and the amount of air for combustion is controlled
by the air regulator (Y). Minimum load is set by loosening the screw (X) and
adjusting the control plate (Z) for the damper powered by the damper motor.
3.11.3 Procedure for setting the amount of air
The air quantity setting for the maximum load is adjusted by turning screw (Y)
with an Allen key. How open the damper must be is determined by the heat
output and overpressure in the boiler as well as other settings on the burner
such as the position of the brake plate. To adjust the burner as quickly and
as easily as possible, adjustments should always start with the maximum
load, as adjustments here also affect the minimum load.
Set the minimum load by adjusting the control plate (Z). By changing settings
on the control plate towards the higher values on the scale, the opening
of the damper powered by the damper motor increases, thus increasing
the amount of air for the combustion process. To reduce the amount of
air, perform the opposite adjustment. When adjusting the minimum load,
you should always make sure that the damper for maximum load is open
far enough so that it has no significant effect on the amount of air for
the minimum load. The adjustment should be performed alternately: first
adjustment of the minimum load followed by adjustment of the maximum
load and then repeat the procedure unless acceptable combustion is
achieved.