Primary Pump - Honeywell SDC Service Manual

Hydraulic Components
7.2.15
NOTE
Function
Bus system

Primary pump

extended running time
7.2.16
NOTE
Function
Boiler circuit pump 2
158
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time delay when a request to the heat generator is withdrawn.
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.
SDC / DHC
EN2H-0221GE51 R0812