19
L.P.G. Burners
Adjusting the air and gas flow rates
To perform the adjustments, unscrew the fixing screws and remove the burner cover.
NOTE: the combustion analysis must be performed with the burner cover fitted!
Startup Output
The start-up heat output shall not exceed 120 kW (single stage burners) or 1/3 of nominal output (double-stage, progressive or fully
modulating burners). In order to comply with these requirements, burners are provided with butterfly valve and/or slow-opening safety
valve.
On double-stage, progressive or modulating burners, the low flame ouptut must be higher than the minimum ouptut quoted in the per-
formance curve (see “Measuring the gas pressure in the combustion head” on page 17).
Adjusting procedure
Check the phase and neutral position.
Check the proper earthening.
(Double-stage burners) Adjust the air and gas flow rates at the maximum output (“high flame”) first, by means of the air damper and
the valves group pressure stabiliser respectively.
Gas
pressure
in
combustion
h
ead
LG70 L-.
Gas rate Stm
3
/h
LG90 L-.
Gas rate Stm
3
/h
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 IMMEDIA-
TELY 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
LPG
11 ÷ 12
2,8 ÷ 4,3
0
1
2
3
4
5
6
7
0,5
1
1,5
2
2,5
3
0
2
4
6
8
10
0,5
1
1,5
2
2,5
3
3,5
