baltur Minicomist 7, Instructions Manual

Page: 26 / 36

26
NATURAL GAS / LIGHT OIL DUAL FUEL BURNERS
This passage must be proportionately opened more when the burner is working with a higher fuel delivery.
This manoeuvre can be carried out by operating the regulating screw of the flame disk.
After having modified the flame disk position, it is then necessary to verify that ignition occurs correctly.
STARTING UP AND REGULATION WITHMETHANE GAS
N.B. Please refer to the last pages where specific instructions are given with regard to regulating the gas delivery
in function with the type of valve fitted on the burner.
In order to proceed with ignition, it is indispensable to carry out a purge of the air contained in the pipeline and
check, if the burner is three-phase, that the sense of rotation of the motor is correct.
Then proceed as follows:
1) Make sure that the discharge of combustion products can take place freely (chimney lock-gates should be
open) and that there is water in the boiler.
2) Open, as much as considered necessary, the combustion air regulator, and open by about one third the air
passage between the head and the disk by operating the regulating screw of the flame disk.
3) Operate the regulators incorporated in the gas valves in such a way as to obtain the gas delivery presumed
necessary.
N.B. Please refer to the last pages where specific instructions are given with regard to regulating the gas
delivery in function with the type of valve fitted on the burner.
4) Give current to the burner by connecting the main switch and the burner switch. The burner is turned on in this
way and will then carry out the pre-ventilation phase. If the air pressure exceeds the value at which the air
pressure switch has been set, the ignition transformer will be connected and, subsequently, the gas valves
will be inserted. The safety valve opens completely while the principle valve, which incorporates the regulation
devices, opens twice. When it opens the first time, it realises the starting output immediately.
The second time, it opens gradually and when it is completely open the burner is operating at the maximum
value at which the maximum output regulator has been set.
At first ignition, successive “shutdowns” can occur, due to the following reasons:
a) The gas pipeline has not been adequately purged of air and therefore the quantity of gas is not sufficient to
allow a stable flame.
b) A “shutdown” with flame presence can be caused by flame instability, due to an incorrect air/gas ratio. This
can be remedied by varying the quantity of air and/or gas delivered, in order to find the correct ratio. It could
also be caused by an incorrect distribution of air/gas in the combustion head.
This can be corrected by operating the regulation device of the combustion head – close more
(by loosening the regulating screw) or open more (by tightening the regulating screw) the air passage between
the head and the gas diffuser. This can be done by operating the regulating screw of the flame disk.
5) With the burner on, adapt delivery to the value which corresponds with the potentiality desired (Methane gas =
8550 kcal/m 3 ), by reading the meter. This output can be modified by operating the special regulator incorporated
in the valve, as explained above.
6) Control that combustion occurs correctly by using the appropriate instruments. The maximum permissible for
Carbon Monoxide (CO) is 0,1%; with a Carbon Dioxide (CO
2
) value of between 8 and 10%.
7) After regulation, turn the burner off and on again several times to check that ignition occurs correctly.
SAFETY CHECKS
After regulation, always check:
1) That the burner stops by “opening” the thermostat and the air and gas pressure switches;
2) The “shut down” by darkening the photoelectric cell (UV).
To unblock the burner, press the appropriate pushbutton.