420010347701 Dual 1-2-3-4-5 P / MC
EN
ADJUSTMENT OF GAS MINIMUM PRESSURE SWITCH
Unscrew off and remove cover M. - Set regulator N to a value equal to 60% of gas nominal feed pressure
(i.e. for nat. gas nom. pressure = 20 mbar, set regulator to a value of 12 mbar; for L.P.G. nom. pressure
of G30/G31- 30/37 mbar, set regulator to a value of 18 mbar).Screw up cover M
DJUSTMENT OF THE AIR PRESSURE SWITCH
Unscrew screws A and B and remove cover C.- Set the pressure switch to the minimum by turning
regulator D to position 1.
- Start the burner and keep in low flame running, while checking that combustion is correct. Through
a small cardboard, progressively obstruct the air intake until to obtain a CO2 increase of 0,5÷0,8% or else, if a pres-
sure gauge is available, connected to pressure port E, until reaching a pressure drop of 1 mbar (10 mm of
W.G.). - Slowly increase the adjustment value of the air pressure switch until to have the burner
lockout. Remove the obstruction from the air intake, screw on the cover C and start the burner by
pressing the control box rearm button.
Note: The pressure measured at pressure port E must be within the limits of the pressure switch
working range. If not, loose the locking nut of screw F and gradually turn the same: clockwise to
reduce the pressure; counterclockwise to increase. At the end tighten the locking nut.
After putting the burner to the gas position, keep the same regulation of the air selected with the head regula-
tion lever. For getting an optimal efficiency by gas and by oil combustion make the gas distribution by fol-
lowing the airflow. Turn the switch on gas "2" position.
Bleed the air of the pipe across the test point of pressure gauge and check the obtained pressure. Ignite the
burner putting the switch on "ON" position.
The control box will only select the fan motor. The burner will make a preliminary pre-purge. During this
time the air pressure switch send all information about the ventilation to the control box. After the prelimi-
nary pre-purge, the control box opens the 1st stage gas valve and the safety one giving power to the transfor-
mer.
If the burner works correctly, the ignition transformer automatically switches off at the end of the control box
cycle. Put the switch I/II on the I position to keep the burner at the first stage. Adjust the gas flow rate com-
plying with the preliminary head setting to let the combustion reach the optimal efficiency at first stage.
The burner will stay at the first stage till the switch is not positioned again on the second position. Then the
control box starts the second stage opening the air damper and the second stage valve.
Set another time the gas flow rate to get an optimal efficiency of the two stages combustion. On normal
working conditions the second stage automatically starts after 24 seconds. The burner is now set to work on
optimal conditions whether gas or oil.
Ignite the burner putting the switch "ON". The electronic regulator of the flame is cyclic; it always starts
from the same position. The regulator let work the fan and the motor pump. The burner will do a prelimi-
nary pre-purge.
During this time the air pressure switch send all information about the ventilation to the control box. After
the pre-purge, the control box opens the 1st stage oil valve and the safety one; the transformer turns on.
If the burner works correctly the ignition transformer automatically switches off at the end of the control box
cycle.
IONIZATION CURRENT
Microammeter
full-scale 1000 A
MAX Ri 5000 Ohm
-
UV CELL
+
WORKING OF THE GAS BURNER
control-box LANDIS
LGB 21
1 2
-
+
18
N
M
I
L
D
C
A
G
B
Minimum current necessary to operate
is 200 µA ( SIEMENS ).
H
E
F