Hydraulic Components
SDC / DHC
158 EN2H-0221GE51
R0808
7.2.15 Primary pump
Function only active if the PRIMARY PUMP function was
assigned to one of the outputs variable output 1 or variable output
2 in the "Hydraulics" menu.
The primary pump is the functional equivalent of a loading pump.
It is only active when heating demand to the heat generator is
present. Hot-water requests are not considered.
A primary pump connected to the central device under address 10
will start up as soon as any request is present on the data bus
(including all heating and hot-water circuits within the control
network).
A primary pump connected to an extension controller (address 20,
30 ... 50) runs only upon a demand from the heating circuits
associated with the respective control device.
To avoid a high-temperature safety switch-off of the heat
generator, the primary pump is switched off according to the set
time delay when a request to the heat generator is withdrawn.
7.2.16 Boiler circuit pump
This function is only active if the BOILER CIRCUIT PUMP 1
function was assigned to one of the outputs, i.e. direct heating
circuit pump, variable output 1 or variable output 2, in the
"Hydraulics" menu.
This function is mainly used with multi-boiler systems with
thermohydraulic distributors and is used for water-side cut-off of a
heat generator not in use. The variable output controls a boiler
circuit pump with a non-return valve with a faulty spring or a
motorised shut-off device. The function becomes active
immediately upon demand for the heat exchanger. The heat
exchanger is not enabled until the set pre-running time expires.
Once the heat generator switches off, the variable output remains
active for the duration of the set extended running time.
For systems with two individual boilers or a double boiler, two
boiler circuit pumps can be connected. The second output then
controls the boiler circuit pump of the downstream boiler.
NOTE
Function
Bus system
Primary pump
extended running time
NOTE
Function
Boiler circuit pump 2
