Bosch SSB1000 TL - Cascade - Power Balance Mode (Rev. 4.0.905.15906)

SSB 6720892984 (2019/02) US
BURNERS cascade | 15
Relevant variables
Specic Parameters Level
(Default)
Value
Settable
°C °F °C °F
Delay_ Period_Start_Next_
Burner
[min]
Start Delay Time
2: Installer
3
(min)
1..15
Delay_ Period_Stop_Last_
Burner
[min]
Stop Delay Time
2: Installer
3
(min)
1..15
Quick_Delay_ Period_
Start_Next_Burner
[sec]
Quick Start Interval
2: Installer
30
(sec)
5..300
Quick_Delay_ Period_
Stop_Last_Burner
[sec]
Quick Stop Interval
2: Installer
30
(sec)
5..300
Hyst_Down_Start_Burner
[°C/°F]
Start Burner Diff
2: Installer 5 9 0..20 0..36
Hyst_Up_Stop_Burner
[°C/°F]
Stop Burner Diff
2: Installer 5 9 0..20 0..36
Hyst_Up_Stop_All
[°C/°F]
Stop Burner Diff
2: Installer 30 54 30 54
Hyst_Down_Quick_Start
[°C/°F]
Start Burner Diff in short time
2: Installer 10 18 0..20 0..36
Hyst_Up_Quick_Stop
[°C/°F]
Stop Burner Diff in short time
2: Installer 10 18 0..20 0..36
3.3.5 Cascade – power balance mode (Rev. 4.0.905.15906)
Two different power control modes can be selected to operate the
cascade system.
• Power mode 0:
Power control disabled, each burner modulates based on the system
setpoint.
• Power mode 1:
Power control algorithm to have a minimum amount of boilers/burners
active.
• Power mode 2:
Power control algorithm to have a maximum amount of boilers/
burners active.
• Power mode 3:
Power control algorithm to have a balanced amount of boilers/burners
active.
3.3.5.1 Power mode 1 - Minimum burners on (Rev. 4.0.905.15906)
Power Mode 1 guarantees to have as minimum as possible dependent
ON in order to reach the
T_System .
The modulation of most boilers/burners is forced to 100%, and the last 2
boilers/burners are PID controlled by the setpoint (
Cascade_Setpoint )
from the managing burner in relation to the system temperature (
T_
System
).
The last 2 boilers/burners are modulating to make sure that the power
can be adapted to the system temperature without continuous cycling of
the last burner(s).
Below is a picture that shows an example with 4 boilers/burners.
Burner Startup
The next burner is started under the following conditions:
• At least one PID controlled depending is operating at a power [%] >
Start_Rate_Next_Burner [%].
The managing burner forces another burner to 100% power and waits
for 3 min. (
Delay_Period_Start_Next_Dependent , settable)
before another burner can be started.
Burner shut down
The last started burner will be stopped under the following conditions:
• All PID controlled depending in burn state Power [%] <
Stop_Rate_
Last_Burner
[%]. The managing burner releases another burner
for PID control and waits for 3 min.(
Delay_Period_Stop_Next_
Dependent
, settable) before another burner can be stopped.
Relevant variables
Specic Parameters Level
(Default)
Value
Range
°C °F °C °F
Power_Mode 2: Installer 3 0..3
Start_Rate_Next_Burner
[%]
Threshold rate before start the
next Burner. Condition: at least 1
depending in burn state power [%] >
Start_Rate_Next_Burner [%]
2: Installer 80 1..100
Stop_Rate_Last_Burner
[%]
Threshold rate before start the next
Burner. Condition: all depending in
burn state Power [%] < Stop_Rate_
Next_Burner [%]
2: Installer 25 1..100
Delay_ Period_Start_Next_
Burner
[min]
When the timeout is over the last
dependent can be started
2: Installer 3 1..15
Delay_ Period_Stop_Last_
Burner
[min]
When the timeout is over the last
Burner can be stopped
2: Installer 3 1..15
Hyst_Up_Stop_Burner
Hysterese to stop Burner. Condition:
T_System above Header_Setpoint
plus Hyst_Up_Stop_ Burner
2: Installer 5 9 0..20 0..36
Hyst_ Down_Start_Burner
[sec]
Hysterese to stop Burner. Condition:
T_System below Header_Setpoint
plus Hyst_Up_Stop_Burner
2: Installer 5 9 0..20 0..36