Bosch SSB1000 SA, Manual, Page: 13 / 84

SSB 6720892984 (2019/02) US
BURNERS cascade | 13
3 .3 .4 Cascade – start/stop sequence (Rev. 3.0.0.12315)
The managing burner sends the calculated
Cascade_Setpoint
to the dependent burners. The power of the burners is PID controlled based on the
Calculated_Setpoint
and
T_Supply
. Depending on the temperature difference between
T_Header and Header_Setpoint
(CH or DHW) the
dependent burners will start or stop using different algorithms.
If a CH or DHW demand request is present, the next dependent burner is always called to ensure that the general (on board) pump of at least one
dependent is always running especially in the case where
T_System
is much higher than the setpoint.
In the latter case the Frost protection setpoint is sent to the dependent burner.
Quick Starting and Stopping Burners
When there is a big difference between the
T_System
and the
Cascade_Setpoint
the call for a start or stop of the next or last depending is done
quicker.
• Quick Starting Burners: If the
T_Syste
m is
Hyst_Down_Quick_Start
degrees below the
Cascade_Setpoint
the burners are started at
intervals of
Quick_Start_Interval
, for example 30 sec.
• Quick Stopping Burners: If the
T_System
is
Hyst_Up_Quick_Stop
degrees above the
Cascade_Setpoint
, the burners are stopped at
intervals of
Quick_Stop_Interval
, for example 30 sec.
Starting and Stopping Burners
With a small difference between
T_System
and the
Cascade_Setpoint
the call for a start or stop of the next or last Dependant burner is executed.