Nibe SMO 20 User guide

Installer manual
Control module
NIBE SMO 20
IHB EN 2235-1
731315

Quick guide
Navigation Ok button (confirm/select)
Back button (back/undo/exit)
Control knob (move/increase/reduce)
A detailed explanation of the button functions can be found on page 30.
How to scroll through menus and make different settings is described on page 32.
temperature 1.1
Set the indoor climate
2X
INDOOR CLIMATE
HOT WATER
INFO
HEAT PUMP
The mode for setting the indoor temperature is accessed by pressing the OK button twice, when in the start mode in
the main menu.
INDOOR CLIMATE
HOT WATER
INFO
HEAT PUMP
off
temporary lux 2.1
3 hrs
6 hrs
12 hrs
one time
increase
Increase hot water volume
2X
1X
To increase the amount of hot water temporarily (if a water heater is installed), first turn the control knob to select
menu 2 (water droplet) and then press the OK button twice.

41 Important information
4Safety information
4Symbols
4Marking
5Serial number
5Recovery
6Inspection of the installation
7System solutions
92 Delivery and handling
9Mounting
9Removing the cover
9Supplied components
103 The Control Module Design
10General
114 Installing the installation
11General
11Software version
12Symbol key
12Connecting air/water heat pump
13Climate system
13Cold and hot water
14Installation alternative
165 Electrical connections
16General
18Connections
22Optional connections
25Connecting accessories
266 Commissioning and adjusting
26Preparations
26Commissioning
26Commissioning with additional heating only
26Check the reversing valve
26Check AUX socket
27Start-up and inspection
27Setting the cooling/heating curve
307 Control - Introduction
30Display unit
30Menu system
348 Control
34Menu 1 - INDOOR CLIMATE
35Menu 2 - HOT WATER
35Menu 3 - INFO
36Menu 4 - MY SYSTEM
37Menu 5 - SERVICE
429 Service
42Service actions
4510 Disturbances in comfort
45Info-menu
45Manage alarm
45Troubleshooting
46Additional heating only
4711 Accessories
4912 Technical data
49Dimensions
50Technical specifications
51Energy labelling
52Electrical circuit diagram
56Item register
59Contact information
3Table of ContentsNIBE SMO 20
Table of Contents

Safety information
This manual describes installation and service procedures
for implementation by specialists.
The manual must be left with the customer.
This appliance can be used by children
aged from 8 years and above and per-
sons with reduced physical, sensory or
mental capabilities or lack of experience
and knowledge if they have been given
supervision or instruction concerning use
of the appliance in a safe way and under-
stand the hazards involved. Children shall
not play with the appliance. Cleaning and
user maintenance shall not be made by
children without supervision.
This is an original manual. It may not be
translated without the approval of NIBE.
Rights to make any design or technical
modifications are reserved.
©NIBE 2022.
Electrical installation and wiring must be
carried out in accordance with national
provisions.
SMO 20 must be installed via an isolator
switch. The cable area has to be dimen-
sioned based on the fuse rating used.
If the supply cable is damaged, only NIBE,
its service representative or similar author-
ised person may replace it to prevent any
danger and damage.
Symbols
Explanation of symbols that may be present in this manual.
NOTE
This symbol indicates danger to person or machine.
Caution
This symbol indicates important information about
what you should consider when installing or servi-
cing the installation.
TIP
This symbol indicates tips on how to facilitate us-
ing the product.
Marking
Explanation of symbols that may be present on the product’s
label(s).
Danger to person or machine.
!
Read the User Manual.
NIBE SMO 20Chapter 1 | Important information4
Important information

Serial number
The serial number can be found on the top of the cover for
the control module and in the info menu (menu 3.1).
LEK
Serial number
Caution
You need the product's (14 digit) serial number for
servicing and support.
Recovery
Leave the disposal of the packaging to the installer
who installed the product or to special waste sta-
tions.
Do not dispose of used products with normal
household waste. It must be disposed of at a special waste
station or dealer who provides this type of service.
Improper disposal of the product by the user results in ad-
ministrative penalties in accordance with current legislation.
5Chapter 1 | Important informationNIBE SMO 20

Inspection of the installation
Current regulations require the heating installation to be inspected before it is commissioned. The inspection must be
carried out by a suitably qualified person.
In addition, fill in the page for the installation data in the User Manual.
DateSignatureNotesDescription
✔
Electrical connections
Communication, heat pump
Connected supply 230 V
Outside sensor
Temperature sensor, hot water charging
Temperature sensor, hot water top
External supply temperature sensor
External supply temperature sensor after
electric heater
External return line sensor
Charge pump
Shuttle valve
AUX1
AUX2
AUX3
AUX4
AUX5
AUX6
AA2-X4
Miscellaneous
Checking additional heater
Checking the function of the reversing valve
Checking charge pump function
Completed installation check of heat pump
and associated equipment
NIBE SMO 20Chapter 1 | Important information6

System solutions
COMPATIBLE PRODUCTS
The following combinations of products are recommended for control by SMO 20.
LEK
LEK
LEK
LEK
LEK
LEK
LEK
LEK
Volume vessel
Addition
Water heaterCirc. pump
Accumulator
with hot water
heater
HW control
Air/water heat
pump
Control module
UKV 40
UKV 100
UKV 200
UKV 300
UKV 500
ELK 15
ELK 26
ELK 213
VPB 200
VPB 300
VPBS 300
VPB 500
VPB 750-2
VPB 1000
CPD 11-25/65
VPA 200/70
VPA 300/200
VPA 450/300
VPAS 300/450
VST 05
AMS 20-6 /
HBS 20-6
SMO 20
AMS 20-10 /
HBS 20-10
F2050 – 6
F2050 – 10
S2125 – 8
VST 11
AMS 10-12 /
HBS 05-12
F2040 – 12
S2125 – 12
CPD 11-25/75
F2120 – 16
UKV 200
UKV 300
UKV 500
VPB 500
VPB 750-2
VPB 1000
VPA 300/200
VPA 450/300
VPAS 300/450
VST 20
AMS 10-16 /
HBS 05-16
F2040 – 16
F2120 – 20
7Chapter 1 | Important informationNIBE SMO 20

COMPATIBLE AIR/WATER HEAT PUMPS
F2040
F2040-16
Part no. 064 108
F2040-12
Part no. 064 092
F2050
F2050-10
Part no. 064 318
F2050-6
Part no. 064 328
F2120
F2120-20 3x400V
Part no. 064 141
F2120-16 3x400V
Part no. 064 139
S2125
S2125-8 3x400V
Part no. 064 219
S2125-8 1x230V
Part no. 064 220
S2125-12 3x400V
Part no. 064 217
S2125-12 1x230V
Part no. 064 218
NIBE SPLIT HBS 05
HBS 05-12
Part no. 067 480
AMS 10-12
Part no. 064 110
HBS 05-16
Part no. 067 536
AMS 10-16
Part no. 064 035
NIBE SPLIT HBS 20
HBS 20-6
Part no. 067 668
AMS 20-6
Part no. 064 235
HBS 20-10
Part no. 067 819
AMS 20-10
Part no. 064 319
Check the software version of compatible older NIBE
air/water heat pumps, see page 11.
NIBE SMO 20Chapter 1 | Important information8

Mounting
SMO 20 is a separate, electric control module and must be
mounted on a wall.
Caution
The screw type must be adapted to the surface
on which installation is taking place.
110
410
360
110
10
310
215 70
35
Use all mounting points and mount the module upright, flat
against the wall.Leave at least 100 mm of free space around
the module to allow access and make cable routing easier
during installation and servicing.
NOTE
The installation must be carried out in such a way
that IP21 is satisfied.
Removing the cover
The cover of the control module is opened using a Torx 25
screwdriver. Assemble in the reverse order.
3
1
2
LEK
LEK
Supplied components
LEK
Insulation tape
Outdoor temperature sensor
(BT1)
Cable ties
LEK
Aluminium tape
Heating pipe paste
Temperature sensor
9Chapter 2 | Delivery and handlingNIBE SMO 20
Delivery and handling

General
LEK
L N 1 1 0 2 3 4PE
21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
AA4-XF3
SF1
AA4
AA4-XF4
LEK
L N 1 1 0 2 3 4PE
AA2
FC1
AA7
UB2UB1
PZ3
X1
X2
ELECTRICAL COMPONENTS
Base cardAA2
Display unitAA4
USB socketAA4-XF3
Service outlet (No function)AA4-XF4
Extra relay circuit boardAA7
Miniature circuit-breakerFC1
Terminal block, incoming electrical supplyX1
Terminal block, control signal circulation pump,
sensors AUX inputs and heat pump
X2
SwitchSF1
MISCELLANEOUS
Serial number platePZ3
Cable grommet, incoming supply electricity, supply for
accessories
UB1
Cable grommet, communicationUB2
Designations according to standard EN 81346-2.
NIBE SMO 20Chapter 3 | The Control Module Design10
The Control Module Design

General
Pipe installation must be carried out in accordance with
applicable regulations. See manual for compatible NIBE
air/water heat pump for installation of the heat pump.
MINIMUM SYSTEM FLOWS
The pipe dimension should not be less than the recommen-
ded pipe diameter according to the table. However, each
system must be dimensioned individually to manage the
recommended system flows.
The installation must be dimensioned to manage at least
the minimum defrosting flow at 100% pump operation, see
table.
Minimum re-
commended
pipe dimen-
sion (mm)
Minimum re-
commended
pipe dimen-
sion (DN)
Minimum flow
duringdefrost-
ing
(100% pump
speed (l/s)
Air/waterheat
pump
22200.29AMS 10-12/
HBS 05-12
28250.39AMS 10-16/
HBS 05-16
Minimum re-
commended
pipe dimen-
sion (mm)
Minimum re-
commended
pipe dimen-
sion (DN)
Minimum flow
duringdefrost-
ing
(100% pump
speed (l/s)
Air/waterheat
pump
22200.19
AMS 20-6
AMS 20-10
Minimum re-
commended
pipe dimen-
sion (mm)
Minimum re-
commended
pipe dimen-
sion (DN)
Minimum flow
duringdefrost-
ing
(100% pump
speed (l/s)
Air/waterheat
pump
22200.29F2040-12
28250.39F2040-16
Minimum re-
commended
pipe dimen-
sion (mm)
Minimum re-
commended
pipe dimen-
sion (DN)
Minimum flow
duringdefrost-
ing
(100% pump
speed (l/s)
Air/waterheat
pump
22200.19
F2050-6
F2050-10
Minimum re-
commended
pipe dimen-
sion (mm)
Minimum re-
commended
pipe dimen-
sion (DN)
Minimum flow
duringdefrost-
ing
(100% pump
speed (l/s)
Air/waterheat
pump
28250.38
F2120-16
(3x400V)
35320.48
F2120-20
(3x400V)
Minimum re-
commended
pipe dimen-
sion (mm)
Minimum re-
commended
pipe dimen-
sion (DN)
Minimum flow
duringdefrost-
ing
(100% pump
speed (l/s)
Air/waterheat
pump
28250.32
S2125-8
(1x230V)
S2125-8
(3x400V)
S2125-12
(1x230V)
S2125-12
(3x400V)
NOTE
An undersized system can result in damage to the
product and lead to malfunctions.
Software version
Compatible NIBE air/water heat pump has to be equipped
with a control board that, as a minimum, has the software
version given in the following list. The control board’s version
is shown in the heat pump’s display (if applicable) at start-
up.
Software versionProduct
55F2015
55F2016
118F2020
55F2025
55F2026
all versionsF2030
all versionsF2040
all versionsF2050
all versionsF2120
all versionsS2125
all versionsNIBE SPLIT HBS 05:
AMS 10-6 + HBS 05-6
AMS 10-8 + HBS 05-12
AMS 10-12 + HBS 05-12
AMS 10-16 + HBS 05-16
all versionsNIBE SPLIT HBS 20:
AMS 20-6 + HBS 20-6
AMS 20-10 + HBS 20-10
11Chapter 4 | Installing the installationNIBE SMO 20
Installing the installation

Symbol key
MeaningSymbol
Shut-off valve
Tapping valve
Non-return valve
Mixing valve
Circulation pump
Expansion vessel
Filterball
Pressure gauge
Safety valve
Temperature sensor
Trim valve
Reversing valve/shunt
Cooling system
Air/water heat pump
Radiator system
Control module
Domestic hot water
Addition
Water heater
Hot water circulation
Connecting air/water heat pump
You can find a list of compatible air/water heat pumps in
section "System solutions".
Caution
Also, consult the Installer Manual for your air/water
heat pump.
Install as follows:
•expansion vessel
•pressure gauge
•safety valve / safety valves
Some heat pump models have a factory-fitted safety
valve.
•drain valve
For draining the heat pump during prolonged power fail-
ures. Only for heat pumps that do not have a gas separat-
or.
•non-return valve
A non-return valve is only required in those installations
where the placement of the products in relation to each
other can cause self-circulation.
If the heat pump is already fitted with a non-return valve,
there is no need to install another.
•charge pump
•shut-off valve
To facilitate any future servicing.
•filterball or particle filter
Installed before connection "heating medium return" (XL2)
(the lower connection) on the vacuum pump.
In installations with a particle filter, the filter is combined
with an additional shut-off valve.
•reversing valve.
If the system is to work with both a climate system and a
water heater.
P
XL1
XL2
NIBE SMO 20Chapter 4 | Installing the installation12

Climate system
A climate system is a system that regulates the indoor
temperature with the help of the control system in SMO 20
and, for example, radiators, underfloor heating, underfloor
cooling, fan coils, etc.
CONNECTING THE CLIMATE SYSTEM
Install as follows:
•supply temperature sensor (BT25)
The sensor indicates when the heat pump will start to
produce heating/cooling for the climate system.
•When connecting to systems with thermostats on all radi-
ators/underfloor heating coils, some of the thermostats
must be removed to ensure there is sufficient flow and
heat generation.
Cold and hot water
Hot water production is activated in the start guide or in
menu 5.2.
The settings for hot water are made in menu 5.1.1.
CONNECTING THE HOT WATER HEATER
Install as follows:
•controlling hot water sensor (BT6)
The sensor is placed in the middle of the water heater.
•displayed hot water sensor (BT7)1
The sensor is optional and is placed in the top of the water
heater.
•shut-off valve
•non-return valve
•pressure relief valve
The safety valve must have a maximum 1.0 MPa (10.0 bar)
opening pressure and be installed on the incoming domest-
ic water line as shown.
•mixing valve
A mixer valve must also be installed, if the factory setting
for hot water is changed. National regulations must be
observed.
1The sensor is factory fitted on some water heater/accumulator
tank models from NIBE.
XL1
XL2
13Chapter 4 | Installing the installationNIBE SMO 20

Installation alternative
SMO 20 can be installed in several different ways, some of
which are shown here.
More information about the alternatives is available at
nibe.eu and in the relevant assembly instructions for the
accessories used. See section "Accessories" for a list of the
accessories that can be used with SMO 20.
HOT WATER CIRCULATION
A circulation pump can be controlled by SMO 20 to circulate
the hot water. The circulating water must have a temperat-
ure that prevents bacterial growth and scalding, and national
standards must be satisfied.
The HWC return is connected to a freestanding water heater.
The circulation pump is activated via AUX input in menu 5.4.
-QZ1-FQ3
-QZ1-GP11-QZ1-RM1-QZ1-RN1
-QZ1
EXTERNAL HEATING MEDIUM PUMP
In installations where there is a large pressure drop in the
system, an external heating medium pump (GP10) can be
used as a supplement.
The installation can also be supplied with an external heating
medium pump, if you want a constant flow in the climate
system.
The heating medium pump is supplemented with a non-re-
turn valve (RM1).
If the installation does not have an external supply temper-
ature sensor (BT25), install this as well.
BUFFER VESSEL UKV
A UKV is an accumulator tank that is suitable for connection
to a heat pump or another external heat source, and it can
have several different applications.
The image shows UKV flow equalisation.
ADDITION
On cold days of the year, when the availability of energy
from the air is lower, the additional heating can compensate
and help to produce heat. The additional heating is also good
to have as assistance, if the heat pump ends up outside its
working range or if it has been blocked for any reason.
Step-controlled/shunt-controlled additional
heat
SMO 20 can, via a control signal, control step-controlled or
shunt-controlled additional heat, which can also be priorit-
ised. The additional heat is used for heat production.
Step-controlled additional heat before QN10
The additional heat is connected before the reversing valve
(QN10) and is controlled via a control signal from SMO 20.
The additional heat can be used for producing both hot water
and heating.
The installation is supplemented with a supply temperature
sensor after additional heat (BT63).
NIBE SMO 20Chapter 4 | Installing the installation14

FIXED CONDENSING
If the heat pump is to work towards an accumulator tank
with fixed condensing, you must connect an external supply
temperature sensor (BT25). The sensor is placed in the tank.
The following menu settings are made:
Menu setting (local variations
may be required)
Menu
Desired temperature in the tank.1.9.3 - min. flow line temp.
Desired temperature in the tank.5.1.2 - max flow line temperature
intermittent5.1.10 - op. mod heat med pump
manual4.2 - op. mode
COOLING
Cooling in 2-pipe system
Cooling and heating are distributed via the same climate
system.
When there is a risk of condensation, components and cli-
mate systems must be insulated against condensation in
accordance with current standards and provisions.
Cooling in 4-pipe system
In homes where you want separate cooling and heating
systems, the accessory VCC 05 / VCC 11 can be connected.
The installation is supplemented with a supply temperature
sensor for cooling (BT64).
-EP45-GP10
-EP45
-EQ1-BT64
15Chapter 4 | Installing the installationNIBE SMO 20

General
•Electrical installation and wiring must be carried out in
accordance with national provisions.
•Disconnect SMO 20 before insulation testing the house
wiring.
•SMO 20 must be installed via an isolator switch. The cable
area has to be dimensioned based on the fuse rating used.
•Use a screened cable for communication with the heat
pump.
•To prevent interference, sensor cables to external connec-
tions must not be laid close to high voltage cables.
•The minimum area of communication and sensor cables
to external connections must be 0.5 mm² up to 50 m, for
example EKKX, LiYY or equivalent.
•When routing a cable into SMO 20, the cable grommets
UB1 and UB2 must be used.
•For an electrical wiring diagram for SMO 20, see the
"Technical specifications" section.
NOTE
Do not start the system before filling up with wa-
ter. Components in the system could be damaged.
NOTE
Electrical installation and any servicing must be
carried out under the supervision of a qualified
electrician. Disconnect the current using the cir-
cuit breaker before carrying out any servicing.
LEK
L N 1 1 0 2 3 4PE
21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
SF1
FC1
UB2UB1
MINIATURE CIRCUIT-BREAKER
The control module operating circuit and parts of its internal
components are internally fused by a miniature circuit
breaker (FC1).
ACCESSIBILITY, ELECTRICAL CONNECTION
Removing the cover, see section "Removing the cover".
TIP
The cover to access the base board is opened us-
ing a Torx 25 screwdriver.
3
1
2
LEK
LEK
NIBE SMO 20Chapter 5 | Electrical connections16
Electrical connections

Dismantling
The display may need to be dismantled to allow easier access
when connecting electrics.
1. Press in the catch on the upper rear side of the display
unit towards you (1) and move the display unit upwards
(2) so that the mountings unhook from the panel.
LEK LEK LEK LEK
b
a
1
2
2. Lift the display unit from its mountings.
LEK LEK LEK LEK
b
a
Mounting
When the electrical connection is ready, the display must
be reinstalled, otherwise the front cover cannot be installed.
1. Align the two lower mountings on the reverse of the
display unit with the two upper holes in the panel as il-
lustrated.
LEK LEK LEK LEK
b
a
2. Secure the display on the panel.
LEK LEK LEK LEK
b
a
CABLE LOCK
Use a suitable tool to release/lock cables in the heat pump
terminal blocks.
Terminal block on circuit board
LEK
1
1
2
2
3
3
1
2
3
3
4
1
2
LEK
1
1
2
2
3
3
1
2
3
3
4
1
2
1
2
17Chapter 5 | Electrical connectionsNIBE SMO 20

Connections
POWER CONNECTION
SMO 20 must be installed via an isolator switch with a min-
imum breaking gap of 3mm. Minimum cable area must be
sized according to the fuse rating used.
1N
L
X1
LEK
L N 1 1 0 2 3 4PE
21 20 19 18 1716 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
X1
1 1N
L0 432PE
TARIFF CONTROL
If there is a loss of voltage to the compressor in the heat
pump for a certain period, simultaneous blocking of this
must take place via a software-controlled input (AUX input)
in order to avoid alarms, see page 25. Compressor blocking
must be performed on either the control module or on the
air/water heat pump, not on both at the same time.
CONNECTING THE CHARGE PUMP FOR THE
HEAT PUMP
Connect circulation pump (EB101-GP12) to terminal block
X4:5 (PE), X4:6 (N) and X4:7 (230 V) on the base board (AA2)
as illustrated.
Connect control signal for (EB101-GP12) to terminal block
X2:1 (PWM) and X2:2 (GND) as illustrated.
987654
SMO
Externt
PE
L
N
External
SMO20
AA2-X4
EB101-GP12
LEK
L N 1 1 0 2 3 4PE
AA2-X4
2
1
4
3
SMO
Externt
External
SMO20
X2
EB101-GP12
PWM
GND
LEK
L N 1 1 0 2 3 4PE
21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
X2
5
6
7
2
1
8
9
13
12
4
3
11
10
19
20
21
14
18
16
17
15
NIBE SMO 20Chapter 5 | Electrical connections18

COMMUNICATION WITH HEAT PUMP
Connect the heat pump (EB101) to terminal blocks X2:19 (A),
X2:20 (B) and X2:21 (GND) as illustrated.
Connecting to the heat pump
LEK
L N 1 1 0 2 3 4PE
21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
X2
5
6
7
2
1
8
9
13
12
4
3
11
10
19
20
21
14
18
16
17
15
A
B
GND
SMO
19
20
21
18
F2120
2
1
3
4
GND
B
A
6
5
4
3
2
1
A
B
GND
A
B
GND
F2040
A
B
GND
F2030
542 3
1
A
B
GND
F2016/F2026
5 64
2 3
1
A
B
GND
F2015/F2020/F2025/F2300
X2
SMO20
AA21-J2
X5
X5
AA23-X4
X22
F2040/NIBE SPLIT HBS
F2030
F2016/F2026
F2015/F2020/F2025/F2300
S2125/F2120
19Chapter 5 | Electrical connectionsNIBE SMO 20

TEMPERATURE SENSOR INSTALLATION ON
PIPE
LEK
LEK
The temperature sensors are fitted using heat conducting
paste, cable ties (the first cable tie is secured to the pipe in
the middle of the sensor and the other cable tie is mounted
approx. 5 cm after the sensor) and aluminium tape. Then
insulate them using the enclosed insulation tape.
OUTSIDE SENSOR
The outdoor temperature sensor (BT1) is placed in the shade
on a wall facing north or north-west, so it is unaffected, for
example, by the morning sun.
Connect the outdoor temperature sensor to the terminal
blocks X2:3 and X2:6.
If a conduit is used it must be sealed to prevent condensa-
tion in the sensor capsule.
SMO Externt
5
6
7
2
1
4
3
ExternalSMO20
X2
BT1
LEK
L N 1 1 0 2 3 4PE
21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
X2
5
6
7
2
1
8
9
13
12
4
3
11
10
19
20
21
14
18
16
17
15
ROOM SENSOR
SMO 20 can be supplemented with a room sensor (BT50).
The room sensor has a number of functions:
1. Shows current room temperature in the display on
SMO 20.
2. Option of changing the room temperature in °C.
3. Provides the option of fine-tuning the room temperat-
ure.
Install the sensor in a neutral position where the set temper-
ature is wanted.
A suitable location is on a free inner wall in a hall approx. 1.5
m above the floor. It is important that the sensor is not pre-
vented from measuring the correct room temperature, for
example by being located in a recess, between shelves, be-
hind a curtain, above or close to a heat source, in a draught
from an external door or in direct sunlight. Closed radiator
thermostats can also cause problems.
The control module operates without the room sensor, but
if you want to read off the home’s indoor temperature in the
control module’s display, the sensor must be installed.
Connect the room sensor to terminal blocks X2:7 and X2:10.
If the room sensor is to have a controlling function, it is ac-
tivated in menu 1.9.4.
If the room sensor is used in a room with underfloor heating,
it should only have an indicatory function, not control of the
room temperature.
SMO Externt
9
10
11
6
8
7
ExternalSMO20
X2
BT50
LEK
L N 1 1 0 2 3 4PE
21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
X2
5
6
7
2
1
8
9
13
12
4
3
11
10
19
20
21
14
18
16
17
15
Caution
Changes of temperature in accommodation take
time. For example, short time periods in combina-
tion with underfloor heating will not give a notice-
able difference in room temperature.
NIBE SMO 20Chapter 5 | Electrical connections20