Settings for marathon
®
burner with pneumatic linkage
dreizler A 3001 E - 18.12.2015 | A 2003 - 1.10 | EN - 11.11.2010
28
The nominal combustion gas volume flow depends on both gas pressure and gas temperature at the meter,
as well as on atmospheric pressure.
9.5
Presetting of the motorised air damper (pressure side) for MIN load
The presetting for MIN load is done in accordance with the desired control ratio. The higher the de-
sired control ratio, the smaller the MIN position.
Set air damper to an opening angle of between 5 - 30°.
A slot on the front side of the air damper shaft indicates the position of the air damper.
Set the switching cams for MIN load to ensure that the limiter is not depressed in MIN position.
Run to small load (MIN), until the motorised air damper reaches an angle of approx. 5 - 30°.
Set the O
2
content at MIN load to approx. 4% by turning the setting screw
N
.
Check O
2
and CO content at MAX load. Adjust by turning the setting screw
V
where required.
The resulting gas pressure can be estimated with the following rule of thumb:
NOTICE:
Optimised position for MAX with an 80° opening angle for burner model types 5001.4, 10001.1, 10001.2
and 10001.3. A larger opening angle will only effect a new reduction of the max. volume flow rate depending
on flow.
9.6
Setting minimal burner load
Setting the control ratio of e.g. 1:5 (20% : 100%)
Run actuator to MIN load, until 1/3 - 1/5 of MAX load is reached.
Fig. 9-5 Zero point shift N
The zero point shift
N
allows for small corrections of
the gas flow volume al small load (MIN).
N
in the
range -1.5 to +1.5mbar.
Fig. 9-6 Gas/air ratio V
