Nibe SMO 40 Installer Manual page 28

Step-controlled additional heat after the
reversing valve
External step-controlled additional heat can be controlled
by two relays (2 step linear or 3 step binary), which
means that the third relay is used to control the immer-
sion heater in the water heater/accumulator tank.
With the AXC 30 accessory, a further three potential-
free relays can be used for additional heat control, which
then gives an additional 3 linear or 7 binary steps.
Step in occurs with at least 1 minute interval and step
outs with at least 3 seconds interval.
Step 1 is connected to terminal block X2:2 on the addi-
tional relay board (AA7).
Step 2 is connected to terminal block X2:4 on the addi-
tional relay board (AA7).
Step 3 or immersion heater in the water heater/accumu-
lator tank is connected to terminal block X2:6 on the
additional relay board (AA7).
The settings for step controlled additional heat are made
in menu 4.9.3 and menu 5.1.12.
All additional heat can be blocked by connecting a poten-
tial-free switch function to the software-controlled input
on terminal block X6 on the input board (AA3) or terminal
block X2 (see page 31), which is selected in menu 5.4.
-X1
1 2 3 4 5 6
-X2
1 2 1 2 3 3 4 4
L N 1 1 0 PE 2 3 4
AA7-X2
LEK
L N 1 1 0 PE 2 3 4
X1
If the relays are to be used for control voltage, bridge
the supply from terminal block X1:1 toX2:1, X2:3 and
X2:5 on additional relay board (AA7). Connect the neutral
from the external additional heat to terminal block X1:0.
28 Chapter 5 | Electrical connections
X1 AA7-X2
1 0 PE
1 2 3 4 5 6
SMO 40 SMO
Externt
External
A1 A1 A1
-K1 -K2 -K3
A2 A2 A2
SHUNT CONTROLLED ADDITIONAL HEAT
NOTE
Mark up any junction boxes with warnings for
external voltage.
This connection enables an external additional heater,
e.g. an oil boiler, gas boiler or district heating exchanger
to aid with heating.
SMO 40 controls a shunt valve and start signal for the
additional heat using three relays. If the installation
cannot manage to maintain the correct supply temper-
ature, the additional heat starts. When the boiler sensor
(BT52) shows approx. 55 °C, SMO 40 sends a signal to
the shunt (QN11) to open from the additional heat. The
shunt (QN11) is controlled to ensure the true supply
temperature corresponds with the control system's
theoretically calculated set point value. When the heating
demand drops sufficiently so that additional heat is no
longer required, the shunt (QN11) closes completely.
Factory-set minimum operating time for the boiler is 12
hours (can be adjusted in menu 5.1.12).
The settings for shunt controlled additional heat are
made in menu 4.9.3 and menu 5.1.12.
The boiler sensor (BT52) is connected to soft inputs and
selected in menu 5.4.
Connect the shunt motor (QN11) to terminal block X2:4
(230 V V, close) and 6 (230 V V, open) on the additional
relay board (AA7) and terminal block X1:0 (N).
To control switching the additional heat on and off,
connect it to terminal block X2:2 on the extra relay board
(AA7).
All additional heat can be blocked by connecting a poten-
tial-free switch function to the software-controlled input
on terminal block X6 on the input board (AA3), or termin-
al block X2 (see page 31), which is selected in menu
5.4.
-X1
1 2 3 4 5 6
-X2
1 2 1 2 3 3 4 4
L N 1 1 0 PE 2 3 4
AA7-X2
LEK
L N 1 1 0 PE 2 3 4
X1
If the relays are to be used for control voltage, bridge
the supply from terminal block X1:1 toX2:1, X2:3 and
X2:5 on additional relay board (AA7).
X1 AA7-X2
1 0 PE
1 2 3 4 5 6
SMO 40 SMO
Externt
External
QN11
NIBE SMO 40