Control Operations Guide
Bosch Buderus SSB255 | SSB399 | SSB512 Boilers
| 11
Bosch Thermotechnology Corp.
|
03.2018
Data subject to change
Central Heating Mode 5
(Analog 0-10 Vdc Power % Modulation)
CH Mode“5”
- 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 “
Minimum Power
” (par.#15) and
“
Maximum Power
” (par.#14) 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 operate at the corresponding Power %. The Power % will
be based upon the voltage signal and scaled between the Minimum and Maximum
power settings. 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.
Figure 2
OFF
1.0
1.5
2.0
ON
9
Voltage (VDC)
Max Power
Min Power
Modulation
Powe
r (%)
Central Heating
(CH) Mode
Description
Set these Parameters
Parameter #
Description
Default
Range
CH Mode = “5”
Analog 0-10 VDC
Power Modulation
4
System pump overrun
300 sec.
0 – 900 sec.
5
Boiler pump overrun
300 sec.
0 – 900 sec.
7
CH Hysteresis
5.4°F
0 - 36°F
9
Anti-cycle period
180 sec.
10 – 900 sec.
10
Anti-cycle Temp Diff
12.6°F
0 - 36°F
14
Max Power CH
100 %
50 – 100 %
15
Min Power CH/DHW
1%
1 – 30%
24
Design Supply Max.
194°F
80.6 - 194°F
Table 7
