92/327
Building Technologies
Basic Documentation LMV5...
CC1P7550en
6 Fuel-air ratio control (FARC)
22.05.2018
6.4.9 Multistage operation
Multistage operation is only possible when firing on oil. It is possible to parameterize if
multistage or modulating operation is used.
Electronic fuel-air ratio control can be configured for both 2-stage and 3-stage burners.
In this operating mode, the oil actuator is not controlled.
Multistage fuel-air ratio control is defined via different load points. These are the
stationary operating points and separately adjustable switch-on/off points.
Load
Pos.
Air
7550d02E
S2on
S2off
S2
S1
Figure 39: Multistage operation (here: 2-stage)
Between these points, the actuators are adjusted during their continuous travel. The
speeds of the individual actuators are calculated such that they reach their targets at
the same time.
Β
Note!
When parameterizing the multistage operating ramp, the speed of the
slowest
actuator must be taken into consideration!
When changing from stage 1 to stage 2,
switch-on point S2
is approached first, starting
from
operating point S1
. Now, the second fuel valve is opened.
Then, the system is driven to
operating point S2
.
If the output shall be cut back to stage 1,
switch-off point S2
is approached first.
If
switch-off point S2
has not yet been set,
switch-on point S2
is approached and the
fuel valve closed.
Then, the fuel-air ratio position of
operating point S1
is approached again.
The procedure is analogous when switching from stage 2 to stage 3, and back again.
Parameter
Operation Mode (2-stage / 3-stage / modulating)
Curve Settings
(curve position stage: Stage 1...3 and on
and off switching points)
Betr_Rampe_Stuf
Multistage
