baltur COMIST 20 Installation, Use And Maintenance Instruction Manual page 58

ENGLISH
NATURAL GAS IGNITION AND REGULATION
Before starting up, make sure that:
Purge the air contained in the gas pipeline, if it had not been carried
out when connecting the burner to the gas pipeline. As a precaution,
special care should be taken and doors and windows should be
opened.
Open the union on the pipe near the burner and then open the gas
shut-off valves a little way.
• On the basis of the checks carried out, change the gas output in
order to adjust it to the desired value according to boiler power.
• Open the combustion air regulator as necessary and open approx.
a third of the passage of air between disk and head.
• Turn the fuel change-over switch to the "GAS" position.
• Turn on the switch on the control panel.
• This powers on the control box, and the programmer turns on the
burner.
• During the pre-ventilation stage, make sure that the pressure
switch detects the air variation closing the contact.
• If the air pressure switch does not detect sufficient pressure (does
not carry out the exchange) the ignition transformer is not switched
on, nor are the gas valves, and so the equipment is stopped in
lock-out mode.
• The safety valve opens completely whereas the main valve that
incorporates the adjustment elements opens in two stages.
• The first opening stage carries out the trigger flow rate and occurs
instantaneously.
• The second opening stage occurs gradually and at the end of it, the
burner is at the maximum flow rate permitted by the position set on
the maximum flow rate regulator.
• During the first ignition some subsequent "lock-outs" may happen
because the gas pipe has not bled the air out sufficiently, therefore
the gas quantity is not enough to allow for a stable flame.
• With the burner working at the minimum output it is necessary to
visually check the entity and aspect of the flame, and regulate if
necessary (work on gas and air supply).
• Subsequently a check is carried out on the quantity of gas supplied,
by reading the meter.
• If necessary, correct the gas and air output.
• Make sure that combustion is carried out correctly by means of the
relative instruments.
• Carbon monoxide (CO), maximum permitted value = 0.1% with a
carbon dioxide value (CO2) between 8 ÷ 10% for natural gas.
• To optimize the combustion and for a good stability of the flame (no
pulsations) it may be necessary to operate on the regulation device
of the combustion head.
• Normally, you need to decrease the air flow between disk and head
when the burner is running with reduced fuel output.
• Check that the flame detector is triggered.
IMPORTANT
select the fuel change before 10 seconds stops the cyclic relay
and the burner does not start.
• Check for the efficiency of the thermostats or boiler pressure
switches (they should shut down the burner when triggered).
• After this adjustment, turn off the burner and start it again for a few
times to check if ignition is correct.
A Air damper fastening screw.
B Disk head regulating screw; screw in order to open the air
passage, unscrew to close.
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A A
B