C.I.B. UNIGAS
- M03956CR
22
Adjusting air and gas flow rates
Startup Output
The start-up heat output shall not exceed 1/3 the operating maximum output. The minimum gas flow rate must be set in order to reach
an output value lower than 1/3 the nominal output.
Adjustments - brief description
z
Adjust the air and gas flow rates at the maximum output (“high flame”) first, by means of the air damper and the valves group pres-
sure stabiliser respectively.
z
Check that the combustion parameters are in the suggested limits.
z
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 20.
z
Then, adjust the combustion values corresponding to the points between maximum and minimum (progressive -fully modulating
burners only): set the shape of the adjusting cam foil. The adjusting cam sets the air/gas ratio in those points, regulating the ope-
ning-closing of the air damper.
z
.Set, now, the low flame output, acting on the low flame microswitch of the actuator in order to avoid the low flame output increa-
sing too much or that the flues temperature gets too low to cause condensation in the chimney.
To change the burner setting during the testing in the plant, follows the next procedure, according to the model provided.
Adjusting procedure
The burner is factory-set with the combustion head at the position that refers to the "MAX" output. The maximum output setting refers to
the “fully-ahead” position of the combustion head. As for “fully-ahead” position, it means that the head is towards the boiler, “fully-
backward” position means that the head is towards the operator. As far as the reduced output operation, progressively move the com-
busiton head towards the “MIN” position, rotating clockwise the
VRT
screw (see picture below). The
ID
index shows how much the
combustion head moved.
P60 - P65 - P72
ATTENTION:
before starting the burner up, be sure that the manual cutoff valves are open and check that the pres-
sure upstream the gas train complies the value quoted on paragraph “Technical specifications”. Be sure that the
mains switch is closed.
ATTENTION: During commissioning operations, do not let the burner operate with insufficient air flow (danger of
formation of carbon monoxide); if this should happen, make the gas decrease slowly until the normal combustion
values are achieved.
WARNING: NEVER LOOSE THE SEALED SCREWS! OTHERWISE, THE DEVICE WARRANTY WILL BE INVALIDATE!
IMPORTANT! the combustion air excess must be adjusted according to the in the following chart:
Recommended combustion parameters
Fuel
Recommended (%) CO
2
Recommended (%) O
2
Natural gas
9 ÷ 10
3 ÷ 4.8
MAX
VRT
MIN
ID
