19
Start-up
Gas start-up mode
Gas operating mode
General safety function
Gas starting function
If there is a demand for heat by the fur-
nace system the burner control circuit
will be closed and the program flow
started. At the end of the program flow
the burner will start.
Prior to any burner start and after
burner stop the gas valve will be
automatically tested for proper tight-
ness. The necessity results from the
legal provisions that apply to the
heating system.
The air damper will be closed at bur-
ner stop.
The electric actuator will move the clo-
sed air damper into its full-load position
so that the burner ventilates the furnace
and the exhaust ducts with the speci-
fied air flow rate. Shortly after pre-venti-
lation start the air failure cut-out must
change over to working position, i.e. the
preset minimum air pressure must be
reached and maintained until the burner
is turned off. After the expiry of the pre-
set pre-ventilation time the air damper
and the gas control damper are set to
their partial-load positions.
The ignition transformer is commis-
sioned. Following the pre-ignition
period, the ignition gas solenoid valves
are opened and gas flows into the pilot
burner. The ignition gas is ignited by the
ignition electrodes on the pilot burner.
The UV radiation of the pilot light is now
monitored by the flame sensor (1st
safety period), and the safety shut-off
valves are opened. The gas is supplied
to the gas nozzles by way of the gas
control butterfly, the combustion air by
the ventilator. Both media are thor-
oughly mixed in the mixing unit and
ignited by the pilot light.
The ignition gas solenoid valves then
close and the pilot light goes out. By the
end of the 2nd safety period, the radia-
tion of the main flame must have been
detected by the flame sensor.
Gas operating function
After flame formation, the burner will
shortly remain in the separately set igni-
tion load und is then run at minimum
output.This brings the burner to its ope-
rating position. The controller will now
automatically control the burner bet-
ween its partial-load and full-load positi-
ons.
Depending on the heat demand the out-
put controller will actuate the electronic
compound controller which in turn will
control the actuators of the gas control
damper and air control dampers and
increase or decrease the flow rates
according to a specific program.
The stepless control makes it possible
to operate the burner at any desired
stage between its partial-load and full-
load positions.
For turning off the burner this must
always be in its partial-load position.
The air damper will be closed when the
burner is in its off position so as to pre-
vent cold air from flowing through the
furnace chamber, heat exchanger and
chimney. The interior cooling losses will
be greatly minimised.
Attention:
If there are shut-off dampers in the flue
gas tract they must be complete open.
Otherwise there will be a high dan-
ger of low-speed detonation or
explosion!
The open-position of the
shut-oft damper can be assured by the
integration of the opening contact of the
shut-off damper in the safety chain of
the heat generator.
General safety functions
In case a flame does not develop when
starting the burner (fuel release), the
burner controller will shut off at the end
of the safety period (shut-off on trou-
ble).. A shut-off on trouble will also
occur in the case of flame failure during
operation, air flow failure during the pre-
ventilation phase and pressure failure
during the whole period of burner ope-
ration. Any failure of the flame signal at
the end of the safety period and a flame
signal during the pre-ventilation phase
(external light control) will result in a
shut-off on trouble with the automatic
furnace controller being locked. The
trouble is indicated by the trouble signal
lamp lighting up. The automatic furnace
controller can be unlocked immediately
after a shut-off on trouble by pressing
the unlocking key. The program unit will
return to its starting position and pro-
ceed with the restart of the burner. A
voltage failure will result in a regular
shut-off of the burner.
After voltage recovery, the burner can
be automatically restarted unless
another interlock is active, e.g. one
caused by the safety circuit. In any
case, the fuel oil supply will be imme-
diately stopped upon occurrence of a
trouble.
When using the burner control system
(electronic compound control) all opera-
tional and fault messages may be indi-
cated in plain text on an optionally
available operating and display module.
12/2011 14 072 205
Summary of Contents for Low-NOx N10.12000.30 G-EU2
Page 33: ...34 Manufacturer s declaration...
