Natural Gas Starting Up And Regulation - baltur BTG 3.6 P Notice D'instructions

NATURAL GAS STARTING UP AND REGULATION

(for LPG operation see the relative chapter)
In order to proceed with starting up, it's necessary, if the burner
is three-phase, to check that the sense of rotation of the motor is
correct. If not already done so at the moment of connecting the
burner to the gas pipeline, it's indispensable to carry a purge of the
air contained in the pipeline. As a precaution, special care should
be taken and doors and windows should be opened. Open the pipe
union on the pipeline situated near the burner and then open a little
the cut-off cock (or cocks).When the characteristic odour of gas
can be smelled, close the cut-off cock. Wait until the gas present
in the room has dispersed, and then reconnect the burner to the
gas pipeline. 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, (see 8920/1 - 8943) and open by about one third the
air passage between the head and the flame disk (diffuser) (see
"Regulation of the combustion Head").
3) Operate the regulators incorporated in the gas valves in such
a way as to obtain the gas delivery presumed necessary (see
0002910310).
4) Disconnect the 2nd flame thermostat and give current to the
burner by opening the main switch.
The burners is then turned on and carries out the pre-ventilation
phase. If the air pressure exceeds that value at which the air
pressure switch has been set, the ignition transformer will be
connected and, subsequently, the gas valves (safety and 1st
flame) will be inserted.
The valves open completely and gas delivery is limited to the
position at which the flow regulator incorporated in the 1st flame
valve has been manually regulated. At first ignition, successive
"shut downs" could 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
for a stable flame.
b - A "shut down" with flame presence could be caused by flame
instability in the ionisation zone, due to and 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 by closing or
opening more the air passage between the head and the gas
diffuser. See chapter "regulation of the combustion head".
c - It could happen that the ionisation current is help up by
the current discharged from the ignition transformer (the
two currents have to run the same course on the burner's
"earth") and so the burner goes to "shut down" due to
insufficient ionisation. This can be remedied by inverting
the input (230V side) of the ignition transformer (change the
places of the two wire that take voltage to the transformer).
A shut down with flame presence could also be caused
by the burner's casing not being properly "grounded".
We must point out that the minimum value of the ionisation
current to ensure the working of the control box is shown
in the electrical diagram; normally the ionisation current is
decidedly higher. To check the ionisation current, connect
a microammeter with an adequate scale "in series" to the
ionisation circuit. The cable of the ionisation electrode is
equipped with a connector (see circuit diagram) to facilitate
the micro-ammeter connection. The high isolation wire that
comes from the electrode must be inserted to the negative
(sign -) of the microammeter.
5) With the burner on, adapt delivery to that desired (methane gas
= 8550 kcal/m ) by reading the meter. Take two readings, the
3
second one exactly one minute after the first one. The difference
between the two readings schould be multiplied by in order to ob-
tain the flow per hour (60 minutes). This output can be modified
by operating the special regulator incorporated in the valve (see
the last pages for a desciption of how to regulate the valves).
6) Control that combustion occurs correctly by using the appropriate
instruments (CO
7) After regulation, turn the burner off and on again several times
to check that ignition occurs correctly. With the burner discon-
nected from the main switch, connect the 2nd flame thermostat
and regulate the special device on the servomotor in such a way
as to obtain an opening of the air shutter presumed necessary
for the 2nd flame (see BT 8920/1). Open as well the gas flow
regulator incorporated in the valve to allow for the correct
delivery presumed necessary for the 2nd flame (main flame).
8) Now close the main switch to start up the burner. When the
burner has started up it is necessary to check, as previously
shown, the gas delivery and the combustion with the appropriate
instruments. When the results are known, if necessary, proceed
with varying the gas delivery and the relative combustion air
in order to adapt delivery to that required for the specific case
(boiler potentiality). It is also necessary to check if the CO
CO values are adequate (CO
gas and CO = 0.1%).
9) Control the efficiency of the safety devices: the "shut
down" (by detaching the ionisation electrode cable), the
air pressure switch, the gas pressure switch, the gas pressure
switch and the thermostats).
The pressure switch is self-controlled and trefore it must
!
close the contact, which is foreseen to be closed at rest, (fan
stops and consequently there is an absence of air pressure
in the burner); if it does not, the control box will not be inser-
ted (the burner remains at as standstill). It must be specified
that if the contact is not closed during working, the control
box will carry out its cycle, but the ignition transformer will
not be inserted and the gas valves will not open. Conse-
quently, the burner will go to shut down. Check that the air
pressure switch functions properly with burner operating at
1st flame only, increase the regulating value until it reaches
intervention point and the burner should go to shut down. To
ublock the burner, press the special pushbutton and return
the pressure switch regulator to a sufficient value in order to
measure the air pressure existing during the pre-ventilation
phase.
7 / 20
0006080763_201008
= about 10% for methane gas - CO max. = 0.1%).
2
max. = about 10% for Methane
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