PART III: OPERATION
38
Progressive burners
Once the procedure till step 8 described on paragraph “” on page 30, is accomplished, go on as follows:
9
set the low flame cam matching the high flame cam;
10 set the
TAB
thermostat to the minimum in order that the actuator moves progressively towards the low flame position;;
The manual air damper control is not provided on these actuators. The adjustments must be carried out acting manually on the cams.
11 move the low flame cam to the minimum to move the actuator towards the low flame until the two bearings find the adjusting screw
that refers to the lower position: screw
V
to increase the rate, unscrew to decrease.
12 Move again the low flame cam towards the minimum to meet the next screw on the adjusting cam and repeat the previous step; go
on this way as to reach the desired low flame point.
13 Now adjust the pressure switches (see page 42).
14 If it is necessary to change the burner output in the low flame stage, move the low flame cam: the low flame position matches the
ignition position. As far as burners fitted with Dungs MBC gas valves, the low flame cam does not match the ignition cam position,
that is why it must be set at about 30° more than the ignition cam.
15 Turn the burner off and then start it up again. If the adjustment is not correct, repeat the previous steps.
Fully modulating burners
To adjust the fully-modulating burners, use the
S3
switch on the burner control panel (see next picture), instead of the
TAB
thermostat
as described on the previous paragraphs about the progressive burners. Go on adjusting the burner as described before, paying atten-
tion to use the CMF switch intead of
TAB
.
The
S3
position sets the oprating stages: to drive the burner to the high-flame stage, set S3=MAX; to drive it to the low-flame stage, set
S3=MIN.
To move the adjusting cam set S3=MIN or MAX and then S3=MAN.
Berger STA12B3.41 (progressive and fully modulating burners)
Siemens SQN72.6A4Axx (progressive and fully modulating burners )
For DUNGS MB-DLE / Siemens VGD gas valves
Actuator camsBerger
STA
Siemens SQN72
High flame position (set to 90°)
ST2
I (
red
)
Low flame and ignition position
ST1
III (
orange
)
Stand-by position (set to 0°)
ST0
II (
blue
)
Not used
MV
IV (
black
)
MV
ST2
ST1
ST0
IV
III
II
I
AUTO/MAN
VF
SC
SV
ID
V
SV
Gas butterfly valve clo
s
ed
Gas butterfly valve open
MAN stop at the current position
MAX high flame operation
MIN low flame operation
AUTO automatic operation
MAX
MIN
AUTO
MAN.
S3