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
S1255 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. In those cases where
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 the electric additional heat
is operating, there is a risk of the property’s main fuses
tripping. S1255 is equipped with a load monitor which, with
the aid of a current sensor, controls the power steps for the
electric additional heat by redistributing the power between
the different phases or by disengaging the electric additional
heat in event of an overload in a phase. If the overload re-
mains despite the electric additional heat being disengaged,
the compressor winds down. Reconnection occurs when
the other current consumption drops.
Caution
Activate phase detection in menu 7.1.9 for full
functionality, if current sensors are installed.
Connecting current sensors
A current sensor should be installed on each incoming phase
conductor in to the distribution box to measure the current.
The distribution box is an appropriate installation point.
Connect the current sensors to a multi-core cable in an en-
closure directly adjacent to the electrical distribution unit.
The multi-core cable between the enclosure and S1255 must
have a cable area of at least 0.5 mm².
Electrical distribution unit
NIBE product
Incoming electricity
Connect the cable to terminal block AA2-X30:9-12, where
X30:9 is the common terminal block for the three current
sensors.
+5V
BE1
BE2
BE3
BE1 BE2 BE3
11
10
9
8
12
GND
AA2-X30
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 pump models with multi-installation
functionality from NIBE can be connected to S1255.
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.
NOTE
When several heat pumps are connected together,
an external supply temperature sensor (BT25) and
an external return line sensor (BT71) must be used.
Connect the communication cables between the heat pumps
as illustrated in series to terminal block X30:1 (GND), X30:2
(+12V), X30:3 (B) and X30:4 (A) on the base board (AA2).
The example shows the connection of several S1255 .
Huvudenhet Värmepump 2 Värmepump 3
2 3 41
B
A
GND
+12V
AA2-X30 AA2-X30 AA2-X30
2 3 41
B
A
GND
+12V
2 3 41
B
A
GND
+12V
Main unit
Heat pump 2 Heat pump 3
Connecting accessories
Instructions for connecting accessories are provided in the
manual accompanying the accessory. See section "Accessor-
ies" for a list of the accessories that can be used with S1255.
Connection for communication with the most common ac-
cessories is shown here.
NIBE S1255Chapter 5 | Electrical connections22
To Next Page
Loading...
