Bosch Buderus SSB399 Control Operations Manual page 10

1 0 | Bosch Buderus SSB255 | SSB399 | SSB512 Boilers
Central Heating Mode 4
(Analog 0-10 Vdc Setpoint Control)
CH Mode"4" - Boiler demand is generated by a 0-10 Vdc analog signal from a
Building Management System (BMS). An initial heat request is generated via a
signal of 1.5 VDC or greater. Boiler modulation between "Design Supply Min"
(par.#23) and "Design Supply Max" (par.#24) will occur between 2 and 10 Vdc.
When a demand voltage of 1.5 VDC or greater is applied the Boiler and CH pump
contacts are energized and the Boiler will target a system supply water temperature
corresponding to the appropriate setpoint temperature based upon the voltage signal
and the minimum and maximum setpoint settings. If the Boiler Supply Temperature
sensor (System Supply Temperature sensor for cascade) exceeds the targeted
setpoint plus "CH Hysteresis" (par.#7) the burner will shut off until the sensor reads
"CH Hysteresis" below the targeted Setpoint Temperature. Once the initial demand
has occurred The Boiler and CH pump contacts will remain energized as long as the
voltage from the BMS remains greater than 1 VDC.
1.0
OFF
Figure 1
Central Heating
Description
(CH) Mode
Analog 0-10 VDC
CH Mode = "4"
Setpoint Control
Table 6
Data subject to change
CH Setpoint Max
CH Setpoint Min
1.5 2.0
ON Modulation
Voltage (Vdc)
Parameter #
4
5
7
9
10
23
24
9
Set these Parameters
Description
System pump overrun
Boiler pump overrun
CH Hysteresis
Anti-cycle period
Anti-cycle Temp Diff
Design Supply Min
Design Supply Max.
Control Operations Guide
Default Range
300 sec. 0 – 900 sec.
300 sec. 0 – 900 sec.
5.4°F 0 - 36°F
180 sec. 10 – 900 sec.
12.6°F 0 - 36°F
68°F 39.2 – 179.6°F
194°F 80.6 - 194°F
03.2018 | Bosch Thermotechnology Corp.