Nibe S1256PC Installer Manual page 21

Activate the meter(s) in menu 7.2 - "Accessory settings"
and then set the desired value ("Energy per pulse" or "Pulses
per kWh") in menu 7.2.19 -"Pulse energy meter".
Load monitor
Integrated load monitor
S1256PC is equipped with a simple form of integrated load
monitor, which limits the power steps for the electric addi-
tional heat by calculating whether future power steps can
be connected to the relevant phase without exceeding the
current for the specified main fuse.
If the current would exceed the specified main fuse, the
power step is not permitted. The size of the property's main
fuse is specified in menu 7.1.9 - "Load monitor".
Load monitor with current sensor
When many power-consuming products are connected in
the property at the same time as electric additional heat is
operating, there is a risk of the property's main fuses trip-
ping.
S1256PC is equipped with a load monitor that, with the help
of a current sensor, controls the power steps for the electric
additional heat by redistributing the power between the
different phases or, alternatively, disengages the electric
additional heat step-by-step if there is an overload in a
phase.
If the overload remains despite the electric additional heat
being disengaged, the compressor is limited.
Reconnection occurs when the other current consumption
is reduced.
The building's phases can have different loads. If the com-
pressor has been connected to a heavily loaded phase, there
is a risk that the compressor output will be restricted and
the electric additional heat will operate longer than expected.
This means that the savings will not be as expected.
Connection and activation of current sensors
1. Install a current sensor on each incoming phase conduct-
or into the electrical distribution unit. This is best done
in the electrical distribution unit.
NIBE S1256PC
2. Connect the current sensors to a multi-core cable in an
enclosure directly adjacent to the electrical distribution
unit. The multi-core cable between the enclosure and
S1256PC must have a cable area of at least 0.5 mm².
Incoming electricity
PEN L L L
1 2 3
Electrical distribution unit
NIBE product
3. Connect the cable to terminal block AA2-X30:9-12,
where X30:9 is the common terminal block for the three
current sensors.
BE1 BE2 BE3
AA2-X30
4. Specify the size of the property's main fuse in menu
7.1.9 - "Load monitor".
5. Activate phase detection in menu 7.1.9 - "Load monitor".
COMMUNICATION
Multi-installation
Several heat pumps can be interconnected by selecting one
heat pump as the main unit and the others as subordinate
heat pumps.
Ground source heat pumps with multi-installation function-
ality from NIBE can be connected to S1256PC.
A further eight heat pumps can be connected to the main
unit. In systems with several heat pumps, each pump must
have a unique name. Only one heat pump can be "Main unit"
and only one can be, for example, "Heat pump 5". Main
unit/heat pump are set in menu 7.3.1.
External temperature sensors and control signals must only
be connected to the main unit, except for external control
of the compressor module.
Chapter 5 | Electrical connections 21