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8 Internal Burner Firing Rate Controller
8.12 Start-up Sequence
The firing rate controller has a startup circuit, in order to slow down the burner's start firing rate.
The startup circuit is run during each new burner start. The internal firing rate is held at a value
P 792 adjustable by the user, for as long as the boiler is cold (actual value is below a user-
adjustable limit, P 791). If the controller’s actual value is equal to or larger than the parame-
terised startup maximum temperature, this startup circuit is cancelled.
In order to prevent a situation where an excessively large demand on system output, the boiler
temperature necessary to cancel the startup circuit is not reached, a startup timer is also trig-
gered in parallel (this timer can also be adjusted by the operator, P 793). Once the internal
firing rate reaches the parameterised startup firing rate, the output is increased linearly step-
wise up to the maximum firing rate. The slope of this linear increase is calculated from the pa-
rameterised startup time.
Nr. FMS ETA
/FA1
Short Text Description Min Max Default
796 0 0 Soll1min Controller setpoint 1 minimum 0 999 90
Firing rate controller setpoint 1 minimum (setpoint 1) in °
C or bar (xx.x)
Set the minimum value for the first controller setpoint
(active if input "set point switching" = 0) (weather guided
controller) in this parameter. If the firing rate controller is
configured as a constant controller, the set point is set
here.
"Set point input via front panel"
1.Selection switch: firing rate value
2.Display: controller setpoint, controller actual value,
firing rate setpoint, internal firing rate
3.Channel key 3 down and channel key 4 up at the
same time
4.Controller setpoint starts to flash and the setpoint can
be changed with channel key 2
5.Do not save value: channel 3 up and channel 4 down
at the same time or switch off burner
6.Save value: save the setpoint to the minimum value
parameter with the Enter key (in P 796 / P 798
depending on the setpoint switching input)
Saving is only possible with constant controller.
With control by atmospheric conditions you may set the
firing rate controller setpoint value default manually
Activation of the controller setpoint modification is disa-
bled when operating mode is OFF. You may not trigger
the burner start by shifting the switching point.
refer to figure "Control by Atmospheric Conditions / Set-
point Switching of the Firing Rate Controller"
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