20
Check that the combustion parameters are in the suggested limits.
Check the flow rate measuring it on the counter or, if it was not possible, verifying the combustion head pressure by means of a dif-
ferential pressure gauge, as described on par. “Measuring the gas pressure in the combustion head” on page 17.
(Double-stage burners) Set, now, the low flame output, acting on the low flame actuator microswitch in order to avoid the low flame
output increasing too much or that the flues temperature gets too low to cause condensation in the chimney.
Adjusting the combustion head
The burner is adjusted in the factory with the combustion head in the position that refers to the "MAX" output. The maximum output set-
ting refers to the “fully-ahead” position of the combustion head, as far as standard models (Fig. 6), and to “fully-backward” position for
low NOx burners (Fig. 7). As for “fully-ahead” position, it means that the head is placed inside the boiler, “fully-backward” position
means that the head is towards the operator. To remove the combsution head, please refer to par. “Removing and cleaning the combu-
stion head” on pag. 53. As far as the reduced output operation, progressively move the combusiton head towards the “MIN” position,
rotating clockwise the
VRT
screw (Fig. 5).
go on adjusting air and gas flow rates: check, continuosly, the flue gas analisys, as to avoid combustion with little air; dose the air
according to the gas flow rate change following the steps quoted below;
To change the burner setting during the testing in the plant, follows the next procedure.
Adjustements for
single-stage burners
1
startup the burner by turning its main switch
A
to on: if the burner locks (LED
B
on in the control panel) press the RESET button (
C
)
on the control panel.
ATTENTION: if the ignition pahse fails, during the first start-up, increase the gas flow rate according to the precedure quoted below.
2
acting on the pressure stabiliser of the valves group, adjust the
gas flow rate in the high flame stage
as to meet the values
requested from the boiler/utilisation:
Pressure controller is provisionally factory-set. The setting values must be locally adapted to machine conditions.
Important: Follow the instructions of the burner manufacturer!
The compact DUNGS gas Multibloc is made of built-in filter, valves, governor and pressure switch.
Fig. 5
Fig. 6 - Head in “fully-ahead position” Fig. 7 - Head in “fully-backward po-
sition”
Fig. 8 -
DUNGS MBC 65-DLE
Fig. 9
Keys
A.
measuring noozle P2 (Fig. 9) before valve D
B.
pressure regulator
C.
startup valve (no. 10 in Fig. 9)
D.
maximum flow rate valve(no. 9 in Fig. 9)
VRT
9
P
2
10
V2
V1
1
P
1
P
3
12