56
7 Internal Burner Firing Rate Controller
7.11 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.
Fig. 7-2 Startup sequence
*(1) = P 792
*(2) = P 793
Nr. FMS ETA Short Text Description Min Max Default
791 0 0 Anf.Temp Max. start-up temperature 0 999 0
Maximum start-up temperature or pressure in relation to
the actual value
Start - up circuit parameter:
Enter the actual temperature, up to which the start - up
circuit is active. See fig. Start - up circuit
792 0 0 Anf.Leis Start-up output 0 999 0
Burner start-up firing rate, corresponding to the internal
firing rate (in digit)
Set the firing rate value at which the burner should start.
see fig. start - up circuit
793 0 0 Anf.Zeit Start-up time 0
32767
0
Burner-start-up-time in seconds
The maximum time the start - up circuit is active is set
here.
see fig. start - up circuit
To Next Page
Loading...
