Potterton SIRIUS FS Installation & Servicing Instructions Manual page 28

0 - 10V direct heating circuit temperature control (H2 Expansion Modules 1-3)
The operation and flow temperature output of the boiler can be controlled directly
using a 0 - 10VDC signal. Once activated, the boilers will remain in operation as long as
the voltage on H2 remains above 0.15 VDC.
NB. This control method cannot be used in conjunction with remote enable to
control the heat output of a heating circuit, as remote enable will turn off this
function. 0-10v only becomes active when the heating circuit(s) are in standby mode.
External / BMS controlled circulation pump essentials
When using a BMS or external control to operate the boiler, it is essential that the
pump circulating water around the boiler is interlocked with the demand for heat from
these controls, so that it should not be possible for the boiler to have a heating demand
without the circulation pump being in operation.
It is also essential that there is adequate provision of an over-run of the circulation
pump after the boiler has satisfied the heating demand, in order to prevent damage to
the heat exchanger. A minimum over-run time of 3 minutes is advised.
NB. Even in standby mode, the built in frost protection program will activate when the
temperature detected inside the boiler drops below 5
switching on its burners, until the water temperature inside the boiler reaches 16
which point the burners switch off and the boiler returns to standby mode again. The
circulation pump MUST operate during this process.
Failure to provide adequate water circulation to the boiler, via operation of a
pump, when the gas burners are in operation may result in heat exchanger
damage and will invalidate the manufacturers warranty.
Sirius FS
QX21
U+
QX22
BX22
N
QX23
BX21
N
Module No
QX21
U+
QX22
BX22
N
QX23
BX21
N
Example of 0‐10V setup using expansion module 1
Siemens Parameter
Parameter description
Function extension
6020
module 1
Function of input H2
6046
module 1
6047 Contact type H2
6049 Voltage valve 1 H2
6050 Function value 1 H2
6051 Voltage valve 2 H2
6052 Function value 2 H2
26
0-10 VDC Output
Parameter setting Notes
H2 can be freely
Multifunctional
configured
0‐10V signal to control
Consumer request
flow temperature
VK2 10V
setpoint
Not relevant to this
NO or NC
function
Voltage at which function
0.5Vdc
value 1 applies
At voltage value 1 the
355 flow temperature
setpoint is 35.5°C
Voltage at which function
10.0Vdc
value 2 applies
At voltage value 2 the
820 flow temperature
setpoint is 82.0°C
C. This results in the boiler
O
C, at
O
GB/IE