24
ELECTRICAL CONNECTIONS
The electric lines should be at an adequate distance from hot parts. It is advisable to make all connections with
flexible electric wire. Minimum section of conductors 1.5 mm
2
. (CEI 64/8 3.I.07).
DESCRIPTION OF OPERATIONS
Switch off the general switch, if the thermostats are off, and voltage goes to the command and control device which,
after a short interval (9 second), will start uf the burner according to the set program. The fan motor goes into
operation and makes the combustion chamber preventilation. At the end of the preventilation phase, the ignition
procedure will then start and, after 3 seconds, the safety valve and “first flame” (pilot light) valve will open up. A flame
will then apper, which will be detected by the flame control device, thus completing the ignition procedure.
The air shutter control servo will then be switched on, which will move to the second flame setting, as set by the
operator in each specific case, and at the same time an auxiliary contact on the servo will activate the second flame
valve. If the flame does not light, the burner will go into the “safety shutdown” state, 3 second after the opening of the
gas valves (pilot and safety). If a “safety shutdown” occurs, the gas valves will be closed immediately.
To go out of the shoutdown state, press the red button on the burner unit.
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 “servomotor for regulating air shutter
type LKS 120-02 (B5-5-51)”) 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.
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 1
st
flame) will be inserted.
The valves open completely and gas delivery is limited to the position at which the flow regulator incorporated in
the 1
st
flame (pilot) 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 (220V 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.
SPARKGAS 3,6 - 6 - 11 P
Содержание SPARKGAS 3,6
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