Flue Temperature Protection (Rev 3.0.0.0); Input Configuration 900Mn (Rev 4.0.905.16712); Output Configuration 900Mn (Rev 4.0.905.16712) - Bosch SSB1000 SA Manual

36 | Main control
Frost protection for boiler cascade
The 'frost protection' function for a burner cascade is related to the boiler
sensor temperatures.
When the boiler sensor temperature or the managing burner supply/
return temperature is below:
Cascade frost protection
The cascade CH/system pump and the general pump of the managing
burner start running.
Cascade frost protection – 5°C
Cascade heat demand is activated to open the optional air damper, the
general pumps of all the burners will be started. Demand with setpoint
Cascade frost protection allows the burners to start burning until the
lowest of both boiler, managing supply and return temperatures are
above Cascade frost protection + 5° C.
Frost protection on burner
As last protection the controllers for the burners can force themselves to
burn.
NOTE: On systems with an air damper this demand will not be served
when the air damper is closed.
If the burner supply/return temperature drops below 5°C (41°F) the
burner starts at minimum power and continues burning until the lowest of
both supply and return temperatures are above 15°C (59°F).
Frost protection in cascades with air damper
To enable frost protection a demand must be generated on the cascade
controller. This is covered by the frost protection and needed because
the air damper must be opened by the cascade controller before a burner
can start.
5 .3 .8 Flue temperature protection (Rev 3 .0 .0 .0)
The flue temperature protection function protects against the flue gas
reaching too high temperatures. Either a flue gas sensor or a flue switch
can be used.
• When the T_Flue or T_Flue_2 sensor measure above the Max_
Flue_Gas_Temp the control generates a Flue_Gas_Error .
• When the Flue_Switch closes the control generates a Flue_Gas_
Error .
When the control is in a Flue_Gas_Error the fan will run at the minimum
fan speed.
Burner power limitation
When a flue gas sensor is connected the control will limit the burner
power when the flue gas temperature reaches the set Max_Flue_Gas_
Temp . The maximum burner power is linearly limited when the flue gas
temperature is within
Max_Flue_Gas_Temp – 5°C and Max_Flue_Gas_Temp .
Relevant variables
Specific
Level
Parameters
Max_Flue_Gas_
3: Factory
Temp
[°C/°F]
6720892984 (2019/02) US
(Default)
Settable
Value
°C °F °C °F
100 212 40...130 104...266
5 .3 .9

Input configuration 900MN (Rev 4.0.905.16712)

There are several multiple function inputs that can be applied for different
types of appliances. The function of the input can be selected via the
epHS display but also with LabVision PC software.
The following input functions can be selected:
Input Description
0 ¨ Disabled
1 ¨ Water pressure sensor
J72-3
2 ¨ CH flow switch
3 ¨ Flue pressure switch
0 ¨ Disabled
J72-4 1 ¨ T_DCW sensor
2 ¨ Water pressure switch
0 ¨ Disabled
1 ¨ DHW flow sensor
J77-8
2 ¨ DHW flow switch
3 ¨ CH flow switch
0 ¨ Disabled
J79-10 1 ¨ Drain switch
2 ¨ Gas pressure switch
0 ¨ T_Supply_2 sensor
J123-6(*) 1 ¨ Disabled
2 ¨ Air damper switch
0 ¨ Disabled
J63-10 1 ¨ T_Return sensor
2 ¨ Vapor switch
0 ¨ Disabled
J64-11 1 ¨ T_DHW sensor
2 ¨ T_Zone sensor
0 ¨ Disabled
1 ¨ T_Fluesensor
J65-12
2 ¨ Flueswitch
3 ¨ APSswitch
0 ¨ Disabled
1 ¨ T_Flue_2 sensor
676-13 2 ¨ T_Flue_2 with blocked flue
3 ¨ T_System sensor
4 ¨ Blocked flue switch
(*) Duplex safety sensors cannot be adjusted freely.
5 .3 .10

Output configuration 900MN (Rev 4.0.905.16712)

There are several multiple function outputs that can be applied for
different types of appliances. The function of the output can be selected
via the epHS display but also with LabVision PC software.
The following outputs are available on the control:
Output Connection
Prog. Output 1 J3 3-8
Prog. Output 2 J3 5-10
Prog. Output 3 J3 6
Prog. Output 4 J3 1-2-7
Prog. Output 5 J3 4-9
Type output
Relay output
Relay output
Relay output
Relay output
Relay output
SSB