Würth IVT Latento System Controller Operating instructions

Installation and operating instructions
Read carefully before installation, commissioning and operation
System Controller

A. - Safety instructions 3
A.1. - EC declaration of conformity 3
A.2. - General instructions 3
A.3. - Explanation of symbols 3
A.4. - Changes to the unit 3
A.5. - Warranty and liability 4
A.6. - About the controller 4
A.7. - Scope of supply 4
A.8. - Disposal and pollutants 4
B. - Description of controller 5
B.1. - Specifications 5
B.2. - Temperature resistance table
for Pt1000 sensors 5
C. - Installation 6
C.1. - Wall installation 6
C.2. - Electrical connection 6
C.3. - Installing the temperature sensors 8
D. - Terminal connection 9
D.1. - Terminal connection 9
D.2. - Terminal connection diagram 9
D.3. - Hydraulic variants / Systems / Diagrams 10
D.4. - RC 21 Room thermostat 14
E. - Operation 15
E.1. - Display and input 15
E.2. - Commissioning help 16
E.3. - Free commissioning 16
E.4 Menu sequence and menu structure 17
1. - Measurement values 18
2. - Statistics 19
2.1. - Today 19
2.2. - 28 days 19
2.3. - Operating hours 19
2.4. - Heat quantity 19
2.5. - Graphic overview 19
2.6. - Message log 19
2.7. - Reset/clear 19
3. - Periods 20
3.1. - Heating circuit day 20
3.2. - Heating circuit 2 day 20
3.3. - Heating comfort 20
3.4. - Heating circuit 2 comfort 20
3.5. - Hot water enable 20
3.6. - Cooling periods 21
3.7. - Thermostat 21
3.8. - Circulation 21
3.9. - Antilegionella 21
3.10. - Time and Date 21
3.11. - Daylight saving time 21
4. - Operating Modes 22
4.1. - Heating circuit 22
4.2. - Manual 22
4.3. - Domestic Hot Water 22
5. - Settings 23
5.1. - Difference 23
5.2. - Heat Transfer 23
5.3. - Booster pump 23
5.4. - Thermostat 23
5.5. - Cooling 23
5.6. - Heating circuit 23
5.6.1. - Summer / Winter Day 23
5.6.2. - Summer / Winter Night 23
5.6.3. - Curve 24
5.6.4. - Day correction 24
5.6.5. - Night correction 24
5.6.6. - Comfort temperature boost 24
5.6.7. - Minimum Flow 25
5.6.8. - Maximum Flow 25
5.6.9. - Reference/actual - 25
5.6.10. - Reference/actual + 25
5.6.11. - Storage HC 25
5.7. - Solid fuel boiler 25
5.8. - Settings Domestic Hot Water (DHW) 25
5.8.1. - Hot water Minimum 25
5.8.2. - DHW reference 26
5.8.3. - DHW Hysteresis 26
5.8.4. - Buffer DHW charge 26
5.8.5. - DHW Priority 26
5.9. - Solar 26
5.10. - Solarbypass 26
5.11. - Heat exchanger 26
5.12. - Burner 26
5.13. - Boiler pump 26
5.14. - Compressor 26
5.15. - Glycol pump 26
5.16. - Storage loading pump 26
5.17. - Heating circuit 2 26
5.18. - Return flow increase 26
5.19. - Circulation 26
5.20. - Error messages 27
5.21. - Pressure control 27
5.22. - Parallel operation R1 27
5.23. - Parallel operation R2 27
5.24. - Mixer 27
5.24.1. - Turn time 27
5.24.2. - Pause factor 27
5.24.3. - Increase 27
5.25. - Room controller 27
5.25.1. - Room controller 27
5.25.2. - Room reference day 27
5.25.3. - Room reference night 27
5.25.4. - RC influence 27
6. - Protective functions 28
6.1. - Anti-seizing protection 28
6.2. - Frost protection 28
6.3. - Antilegionella 29
6.3.1. - AL T set 29
6.3.2. - AL residence time 29
6.3.3. - Last AL heat up 29
6.3.4. - AL sensor 1 29
6.3.5. - AL Sensor 2 29
6.3.6. - AL-times 29
6.4. - Protective functions for Solar 30
6.5. - System protection 30
6.6. - Collector protection 30
6.6.1. - Recooling 30
6.6.2. - Frost protection 31
6.7. - Seizing protection 31
6.8. - Collector alarm 31
6.9. - Buffer discharge protection 31
7. - Special functions 32
7.1. - Program selection 32
7.2. - Speed control 32
7.2.1. - Variant 32
7.2.2. - Type of pump 33
7.2.3. - Pump menu 33
7.2.3.1. - Pump 33
7.2.4. - Purging time 33
7.2.5. - Sweep time 33
7.2.6. - max. speed 33
7.2.7. - min. speed 33
7.3. - Relay functions 34
7.3.1. - Difference 34
7.3.1.1. - Difference 34
7.3.1.2. - T Difference 34
7.3.1.3. - DF source (sensor) 34
7.3.1.4. - Diff Tmin 34
7.3.1.5. - DF Drain (sensor) 34
7.3.1.6. - Diff Tmax 34
7.3.2. - Heat transfer 35
7.3.2.1. - T Heat transfer 35
7.3.2.2. - Setpoint 35
7.3.2.3. - HT Tmin 35
7.3.2.4. - HT Source (sensor) 35
7.3.2.5. - HT Drain (Target sensor) 35
7.3.3. - Booster pump 35
7.3.3.1. - Booster 35
7.3.3.2. - Fill time 35
7.3.4. - Thermostat 36
7.3.4.1. - Thermostat 36
7.3.4.2. - TH Set 36
7.3.4.3. - TH hysteresis 36
7.3.4.4. - Thermostat sensor 1 36
7.3.4.5. - Thermostat sensor 2 36
7.3.4.6. - T eco 36
7.3.4.7. - Energy saving mode 36
7.3.4.8. - Periods 36
7.3.5. - Heating rod 37
7.3.5.1. - Heating rod 37
7.3.5.2. - Request DHW 37
7.3.5.3. - Request HC 37
7.3.5.4. - T set 37
7.3.5.5. - Delay 37
7.3.5.6. - Hysteresis 37
7.3.5.7. - Eco mode 37
7.3.5.8. - Heating rod periods 37
7.3.5.9. - Antilegionella heating rod 37
7.3.6. - Cooling 38
7.3.6.1. - Cooling 38
7.3.6.2. - Co Tref 38
7.3.6.3. - Hysteresis 38
7.3.6.4. - Delay 38
7.3.6.5. - Cooling sensor 38
7.3.6.6. - Cooling periods 38
7.3.7. - Solid fuel boiler 39
7.3.7.1. - Solid fuel boiler 39
7.3.7. 2. - S F Tma x 3 9
7.3.7. 3 . - S F Tmin 39
7.3.7. 4 . - T SF 39
7.3.7. 5 . - B o i ler se n sor 39
7.3.7.6. - Storage sensor 39
7.3.8. - Solar 40
7.3.8.1. - Solar 40
7.3.8.2. - Tmin S (X) 40
7.3.8.3. - T Solar S (X) 40
7.3.8.4. - Tmax S (X) 40
7.3.8.5. - Start aid function 40
7.3.8.6. - Protective functions 40
7.3.9. - Solar bypass 41
7.3.9.1. - Solar bypass 41
7.3.9.2. - Variant 41
7.3.9.3. - Bypass sensor 41
7.3.10. - Heat exchanger 41
7.3.10.1. - Heat exchanger 41
7.3.10.2. - HE sensor 41
7.3.11. - Burner 42
7.3.11.1. - Burner 42
7.3.11.2. - DHW request 42
7.3.11.3. - HC request 42
7.3.11.4. - Antilegionella 42
7.3.11.5. - Burner sensor 42
7.3.11.6. - Delay 42
7.3.11.7. - T eco DHW 42
7.3.11.8. - Burner offset 42
7.3.11.9. - Eco mode (during solar charge) 42
7.3.11.10. - Heating circuit offset 42
7.3.11.11. - BP Tmax 42
7.3.12. - Boiler pump 43
7.3.12.1. - Boiler pump 43
7.3.12.2. - BP Tmin 43
7.3.13. - Compressor 44
7.3.13.1. - Compressor 44
7.3.13.2. - DHW request 44
7.3.13.3. - HC request 44
7.3.13.4. - Heat pump run time 44
7.3.13.5. - Heat pump idle time 44
7.3.13.6. - Heat pump delay 44
7.3.13.7. - Periods 44
7.3.14. - Loading pump 44
7.3.14.1. - Loading pump 44
7.3.14.2. - Loading pump lag 44
7.3.15. - Glycol pump 44
7.3.15.1. - Glycol pump 44
7.3.15.2. - Gylcol pump lag 44
7.3.16. - Heating circuit 2 45
7.3.16.1. - Heating circuit 2 45
7.3.16.2. - S/W Day 45
7.3.16.3. - S/W Night 45
7.3.16.4. - Variant 45
7.3.16.5. - Curve 45
7.3.16.6. - Day correction 46
7.3.16.7. - Night correction 46
7.3.16.8. - Comfort temperature boost 46
7.3.16.9. - Minimum Flow 47
7.3.16.10. - Maximum Flow 47
7.3.16.11. - Reference/actual - 47
7.3.16.12. - Reference/actual + 47
7.3.16.13. - Outdoor sensor 47
7.3.16.14. - Flow sensor 47
7.3.17. - Return flow increase 48
7.3.17.1. - Return flow increase 48
7.3.17.2. - RF Tmin 48
7.3.17.3. - RF Tmax 48
7.3.17.4. - T return flow 48
7.3.17.5. - Return flow (sensor) 48
7.3.17.6. - Storage (sensor) 48
7.3.18. - Domestic hot water valve 48
7.3.19. - Circulation 49
7.3.19.1. - Circulation 49
7.3.20.1. - Circulation Tmin 49
7.3.20.2. - Circulation hysteresis 49
7.3.20.3. - Circulation sensor 49
7.3.20.4. - Circulation pause time 49
7.3.20.5. - Purging time 49
7.3.20.6. - Circulations periods 49
7.3.20. - Messages 49
7.3.21. - Pressure monitor 50
7.3.21.1. - Pressure monitor 50
7.3.21.2. - RPS1 / RPS2 50
7.3.21.3. - Pmin 50
7.3.21.4. - Pmax 50
7.3.22. - Parallel operation R1 50
7.3.22.2. - Parallel operation R (X) 50
7.3.22.1. - Delay 50
7.3.22.3. - Followup time 50
7.3.24. - Always on 50
7.3.23. - Parallel operation R2 50
7.3.25. - Heat quantity 51
7.3.25.1. - Flow sensor (X) 51
7.3.25.2. - Return sensor 51
7.3.25.3. - Anti freeze type 51
7.3.25.4. - Glycole percentage 51
7.3.25.5. - Flow rate (X) 51
7.3.25.6. - Offset T 51
7.3.25.7. - VFS (X) 51
7.3.25.8. - VFS - Position 51
7.3.25.9. - Reference sensor 51
7.3.26. - Pressure monitor 52
7.3.27. - Pressure monitor 52
7.3.27.1. - RPS1 / RPS2 52
7.3.27.2. - Pmin 52
7.3.27.3. - Pmax 52
7.4. - Sensor calibration 52
7.5. - Commissioning 52
7.6. - Factory settings 52
7.7. - SD-Card 53
7.7.1. - Logging 53
7.7.2. - Free storage 53
7.7.3. - Load configuration 53
7.7.4. - Save configuration 53
7.7.5. - F ir mwa re up d ate 5 3
7.7.6. - Unmount 53
7.8. - Sleep mode 53
8. - Menu lock 54
9. - Service values 54
10. - Language 54
Z.1. Malfunctions with error messages 55
Z.2 Replacing the fuse 56
Z.3 Maintenance 56
K. - Appendix 57
K.1. - Pump 57
K.1.1. - Output Signal 57
K.1.2. - PWM off 57
K.1.3. - PWM on 57
K.1.4. - PWM Max 57
K.1.5. - 0-10V off 57
K.1.6. - 0-10V on 57
K.1.7. - 0-10V Max 57
K.1.8. - Speed when „On“ 57
K.1.9. - Show signal 57
Useful notes / Tips and tricks 59
Content

3
Safety instructions
By affixing the CE mark to the unit the manufacturer declares that the Latento System Controller conforms to the relevant
safety regulations
EC low voltage directive 2006/95/EC as well as the EC directive for electromagnetic compatibility 2004/108/EC.
Conformity has been verified and the corresponding documentation and the EC declaration of conformity are kept on file by the
manufacturer.
A.1. - EC declaration of conformity
These installation and operating instructions contain basic instructions and important information regarding safety, installa-
tion, commissioning, maintenance and the optimal use of the unit. Therefore these instructions must be read completely and
understood by the installation technician/specialist and by the system user before installation, commissioning and operation of
the unit.
The valid accident prevention regulations, VDE regulations, the regulations of the local power utility, the applicable DIN-EN
standards and the installation and operating instruction of the additional system components must also be observed. The con-
troller does not under any circumstances replace any safety devices to be provided by the customer!
Installation, electrical connection, commissioning and maintenance of the unit may only be carried out by specialists who pos-
sess the appropriate training.
For the user: Make sure that the specialist gives you detailed information on the function and operation of the controller. Always
keep these instructions in the vicinity of the controller.
A.2. - General instructions
Danger
Caution
A.3. - Explanation of symbols
Failure to observe these instructions can result in danger to life from electric voltage.
Danger
Failure to observe these instructions can result in serious damage to health such as scalding, or even
life-threatening injuries.
Caution
Failure to observe these instructions can result in destruction of the unit or the system, or damage to the
environment.
Information which is especially important for the function and optimal use of the unit and the system.
A.4. - Changes to the unit
• Changes, additions to or conversion of the unit are not permiddled without the written permission from the manufacturer
• It is likewise forbidden to install additional components that have not been tested together with the unit
• If it becomes clear that safe operation of the unit is no longer possible, for example because of damage to the housing,
then turn the controller off immediately
• Any parts of the unit or accessories that are not in perfect condition must be exchanged immediately
• Use only original spare parts and accessories from the manufacturer
• Markings made on the unit at the factory must not be altered, removed or made illegible
• Only the settings actually described in these instructions may be made on the controller
Changes to the unit can compromise the safety and function of the unit or the entire system.
Danger

4
Safety instructions
The controller has been manufactured and tested with regard to high quality and safety requirements. The unit is subject to the
statutory guarantee period of two years from the date of sale.
The warranty and liability shall not include, however, any injury to persons or material damage that is attributable to one or
more of the following causes:
- Failure to observe these installation and operating instructions
- Improper installation, commissioning, maintenance and operation
- Improperly executed repairs
- Unauthorised structural changes to the unit
- Installation of additional components that have not been tested together with the unit
- Any damage resulting from continued use of the unit despite an obvious defect
- Failure to use original spare parts and accessories
- Use of the device for other than its intended purpose
- Operation above or below the limit values listed in the specifications
- Force majeure
A.5. - Warranty and liability
The System Controller Latento System Controller facilitates efficient use and function control of your solar or heating system.
The device is impressive most of all for its functionality and simple, almost self-explanatory operation. For each step in the
input process the individual entry keys are assigned to appropriate functions and explained. The controller menu contains
headwords for the measured values and settings, as well as help texts or clearly-structured graphics.
The Latento System Controller can be used as a system controller for the various system variants illustrated and explained
under „Hydraulic variants / Systems / Diagrams“ on page 12.
Important characteristics of the Latento System Controller:
- Depiction of graphics and texts on an backlit display
- Simple viewing of the current measurement values
- Analysis and monitoring of the system by means of statistical graphics etc.
- Individual configuration of special functions
- Extensive setting menus with explanations
- Menu block can be activated to prevent unintentional setting changes
- Resetting to previously selected values or factory settings
- A wide range of additional functions are available
A.6. - About the controller
- System controller Latento System Controller
- 3 screws 3,5x35mm and 3 plugs 6mm for wall installation
- 12 strain relief clips with 24 screws, replacement fuse 1x T2A / 250V, 1x T630mA / 250V
- Installation and instructions manual Latento System Controller
- Micro SD Card
Optionally contained depending on design/order:
- 2-3 PT1000 temperature sensors and immersion sleeves
- Ethernet
Additionally available:
- Pt1000 temperature sensor, immersion sleeves, overvoltage protection,
- CAN Bus Data Logger
- RC21 Room thermostat with remote adjuster
A.7. - Scope of supply
A.8. - Disposal and pollutants
The unit conforms to the European RoHS directive 2002/95/EC for the restriction of the use of certain hazardous substances
in electrical and electronic equipment.
Caution
The unit must not under any circumstances be disposed of with ordinary household refuse. Dispose of the unit only
at appropriate collection points or ship it back to the seller or manufacturer.

5
Description of controller
B.1. - Specifications
Electrical specifications:
Mains voltage 100 - 240VAC
Mains frequency 50...60Hz
Power consumption 0.5 - 3 W
Switched power
Entire switched power for electronic relays R1 - R2: 460VA for AC1 / 240W for AC3
Electronic relay R1 min.5W...max.120W for AC3
Electronic relay R2 min.5W...max.120W for AC3
Entire switched power for mechanical relays R3 - R6: 460VA for AC1 / 460W for AC3
Mechanical relay R3 460VA for AC1 / 460W for AC3
Mechanical relay R4 460VA for AC1 / 460W for AC3
Mechanical relay R5 460VA for AC1 / 460W for AC3
Mechanical relay R6 460VA for AC1 / 460W for AC3
potentialfree relay R7 460VA for AC1 / 460W for AC3
0..10V Output for 10 k working resistance
PWM Output Freq. 1 kHz, level 10 V
Internal fuse T630mA / 250V slow blow (x3)
4x T2A / 250V slow blow (x1)
Protection category IP40
Protection class II
Sensor inputs 8 x Pt1000
2xGrundfosDirectSensors
1xRC21/RC22
Measuring range
PT1000 -40°C to 300°C
Grundfos Direct Sensor: 0°C-100°C (-25°C /120°C short term)
1 l/min - 12 l/min (VFS1-12)
2 l/min - 40 l/min (VFS2-40)
5 l/min - 100 l/min (VFS5-100)
10 l/min - 200 l/min (VFS10-200)
Network connections
Ethernet(optional)
CANBus
Real Time Clock RTC with 24 hour power reserve
Permissible ambient conditions:
Ambient temperature
for controller operation 0°C...40°C
for transport/storage 0°C...60°C
Air humidity
for controller operation max. 85% rel. humidity at 25°C
for transport/storage no moisture condensation permiddled
Other specifications and dimensions
Housing design 3-part, ABS plastic
Installation methods Wall installation, optionally panel installation
Overall dimensions 228 x 180 x 53 mm
Display Fully graphical display, 128 x 128 dots
Light diode 2: 1x red, 1x green
Operation 4 entry keys
Temperature sensors: (may not be included in the scope of supply)
Collector or boiler sensor Pt1000, e.g. immersion sensor TT/S2 up to 180°C
Storage tank sensor Pt1000, e.g. immersion sensor TT/P4 up to 95°C
Pipe-mounted sensor Pt1000, e.g. pipe mounted sensor TR/P4 up to 95°C
Sensor leads 2x0.75mm² extendable up to 30m max.
B.2. - Temperature resistance table for Pt1000 sensors
°C 0 102030405060708090100
1000 1039 1077 1116 1155 1194 1232 1270 1308 1347 1385

6
Install the controller only
in dry areas and under
the ambient conditions
described under B.1
“Specifications”.
Controller must be inac-
cessible from the rear.
Installation
Caution
Caution
C.1. - Wall installation
1. Unscrew cover screw completely.
2. Remove Terminal connection cover. Unscrew the 2 small screws left and right and
remove the upper part of the controller by lifting it out of the socket.
3. Mark the 3 mounting holes on the wall (see „C.2.1. Socket“). Make sure that the wall
surface is even so that the housing does not become distorted when it is screwed
on.
4. Using a drill and size 6 bit, drill 3 holes at the points marked on the wall and push
in the plugs.
5. Hang the controller on the upper screw.
6. Align the housing and tighten the lower screws.
Controller and VFS sensor have to have the same ground potential. The VFS sensor has a functional earth con-
nector (PELV). The PE-connector of the controller has to be connected to the pipe system near the sensor.
Caution
C.2. - Electrical connection
Danger
Before working on the unit, switch off the power supply and secure it against being switched on again! Check
for the absence of power!
Electrical connections may only be made by a specialist and in compliance with the applicable regulations.
Do not use the controller if the housing shows visible damage.
Caution
Low-voltage cables such as temperature sensor cables must be routed separately from mains voltage cables.
Feed temperature sensor cables only into the left-hand side of the unit, and mains voltage cables only into the
right-hand side.
Caution
The customer must provide an all-pole disconnecting device, e.g. a heating emergency switch.
Caution
The cables being connected to the unit must not be stripped by more than 55mm, and the cable jacket must
reach into the housing just to the other side of the strain relief.
Relay R1 and R2 are only suitable for standard pumps (5-120W) which are speed-controlled via the control-
ler. The internal wiring of the controller is such that residual currents flow over relay R1 and R2 even in the rest
condition. Therefore under no circumstances may valves, contactors or other consumers with lower power
consumption be operated on this output.
Caution

7
Installation
C.2.1. Socket
161
11,8 195,4
9
R4.5
4.4
3333
139,3
n
3.5
169.3
Terminal connection
cover
Cover screw

8
1. Select necessary program/hydraulics (s. „Hydraulic vari-
ants / Systems / Diagrams“ on page 12)
2. Remove terminal connection cover (s. „C.2.1. Socket“ on
page 7)
3. Strip cables by 55mmmax., insert, fit the strain relief de-
vices, strip the last 8-9mm of the wires (Fig. „C.2.2.“)
4. Open the terminals using a suitable screwdriver (Fig.
„C.2.3.“) and make electrical connections on the controller
5. Refit terminal connection cover and fasten screw.
6. Switch on mains voltage and place controller in operation.
C.2.2.
C.2.3.
Installation
The temperature sensor cables must be routed separately from mains voltage cables, and must not, for
example, be routed in the same cable duct!
Caution
Caution
The controller operates with Pt1000 temperature sensors which are accurate to the degree, thus ensuring optimal control of
system functions.
Caution
If desired the sensor cables can be extended to a maximum of 30m using a cable with a cross-section of
at least 0.75mm². Make sure that there is no contact resistance!
Position the sensor precisely in the area to be measured!
Only use immersion, pipe-mounted or flat-mounted sensor suitable for the specific area of application
with the appropriate permissible temperature range.
Connect the VFS sensors with the matching jacks.
To prevent damage to the Direct Sensors it is highly recommended to install them in to the return.
When installing the Vortex Flow Sensors (VFS), observe the correct flow direction!
Instructions for clamps:
1. Insert screw driver into the upper hole. Push the lock
clamp inside down.
Keep the screw driver in this position.
2. Insert cable into the lower opening.
3. Remove screw driver. The clamp will lock the cable.
C.3. - Installing the temperature sensors

9
max. 12V
Caution
Netzseite
230VAC
Danger
V2 V1 S8 S7
VFS2RC21 VFS1 CAN1 CAN2
SD Card
MainsRelaysPF- relayLow Voltage
Ethernet
S6 S5 S4 S3 S2 S1 GND R6NC C NO R5R4R3R2R1 N L
VFS1VFS2
RC21
Bridge
Bridge
Installation
The mains part of the terminal connection room is covered by a plastic sheet. Make sure that the controller is without voltage before
removing it.
D. - Terminal connection
Caution
Low voltage max. 12VAC/DC
Terminal: Connection for:
S1 Sensor 1
S2 Sensor 2
S3 Sensor 3
S4 Sensor 4
S5 Sensor 5
S6 Sensor 6
S7 Sensor 7
S8 Sensor 8
V1 optional speed controlled
output for High efficiency
pumps
V2 optional speed controlled
output for High efficiency
pumps
VFS1 Grundfos Direct Sensor
VFS2 Grundfos Direct Sensor
RC21 Room thermostat +
remote adjuster
Mains voltage 230VAC 50-60Hz
Terminal: Connection for:
R1 Relay 1
R2 Relay 2
R3 Relay 3
R4 Relay 4
R5 Relay 5
R6 Relay 6
N Mains neutral conductor N
L Mains phase conductor L
The PE protective conductor must be
connected to the PE metal terminal
block!
Potential free
Relay
NO
Normally open
C
Common
NC
Normally closed
SD Card Slot
for Data logging
and firmware up-
dates
Make sure the SD
card‘s orientation is
correct!
Card must be
inserted without
pressure. False
insertion can dam-
age the card slot!
Ethernet
for LAN network
operations
CAN connector
D.1. - Terminal connection
D.2. - Terminal connection diagram

10
Installation
D.3. - Hydraulic variants / Systems / Diagrams
System 1
IVT MV A 1 HK
System 2
IVT MV A 2 HK
System 3
IVT MV B 1 HK
System 4
IVT MV C 1 HK
System 5
IVT MV D 1 HK
System 6
IVT MV E 1 HK
system
7
IVT MV
F
S1 Storage Solar (bot-
tom)
Storage Solar (bot-
tom)
Storage Solar (bottom) Storage Solar (bot-
tom)
Storage Solar (bot-
tom)
Storage Solar (bottom) Storage
S
S2 Storage HC (middle) Storage HC (middle) Storage HC (middle) Storage HC (middle) Storage HC (middle) Return sensor Storage
H
S3 Storage DHW (top) Storage DHW (top) Storage DHW (top) Storage DHW (top) Storage DHW (top) Storage Diverses (top) Storage
D
S4 HC2 Flow Return sensor Soild fuel sensor Soild fuel sensor Soild fue
S5 HC1 Flow HC1 Flow HC1 Flow HC1 Flow HC1 Flow HC1 Flow HC1 Flo
w
S6 Burner sensor Burner sensor Burner sensor Burner sensor
S7 Outdoor Outdoor Outdoor Outdoor Outdoor Outdoor Outdoor
S8 Collector Collector Collector Collector Collector Collector Collecto
r
VFS1
VFS2
V1 Signal Solar pump Signal Solar pump
V2
R1
(ELR)
Solar pump Heating pump 1 Solar pump Solar pump Solar pump Soild fuel pump Solar pu
m
R2
(ELR)
Heating pump 2 Boiler pump Returnvalve Soild fuel pump Return valve Soild fue
R3 Mixer 1 open DHW pump Boiler pump DHW pump
R4 Mixer open Mixer 1 close Mixer open Mixer open Mixer open Mixer open Mixer op
e
R5 Mixer close Mixer 2 open Mixer close Mixer close Mixer close Mixer close Mixer cl
o
R6 Heating pump Mixer 2 close Heating pump Heating pump Heating pump Heating pump Heating
p
R7
(Pot.
frei)
Electric heater Electric heater Burner Burner Burner Burner
System
Anschluss
Temperature sensors
Temperature sensors
low voltage only
Relay outputs
Relay outputs
230 VA

11
7
F
1 HK
System 8
IVT MV F 2 HK
System 9
IVT MV G 1 HK
System 10
IVT 2HK+1WEZ+Solar
System 11
IVT 2HK+1WEZ
S
olar (bottom) Storage Solar (bot-
tom)
Storage Solar (bot-
tom)
Storage Solar (bottom)
H
C (middle) Storage HC (middle) Storage HC (middle) Storage HC (middle) Storage HC (middle)
D
HW (top) Storage DHW (top) Storage DHW (top) Storage DHW (top) Storage DHW (top)
l sensor HC2 Flow HC2 Flow
w
HC1 Flow HC1 Flow HC1 Flow HC1 Flow
Soild fuel sensor Burner sensor Burner sensor
Outdoor Outdoor Outdoor Outdoor
r
Collector Collector Collector
Signal Solar pump Signal Solar pump
m
p Heating pump 1 Solar pump Heating pump 1 Heating pump 1
l pump Heating pump 2 Heating pump 2 Heating pump 2
Mixer 1 open Mixer 1 open Mixer 1 open
e
n Mixer 1 close Mixer open Mixer 1 close Mixer 1 close
o
se Mixer 2 open Mixer close Mixer 2 open Mixer 2 open
p
ump Mixer 2 close Heating pump Mixer 2 close Mixer 3 close
Soild fuel pump Compressor Burner Burner

12
Installation
Hydraulic variants / Systems / Diagrams
Temperature sensors
Temperature sensors
low voltage only
Relay outputs
Relay outputs
230 VA
variant
connection
System 12
Combi. storage + Hea-
ting circ.
System 13
Combi. storage+ Com-
pressor+ Load. pump
System 14
Combi. storage+ Solar+
Burner
System 15
Combination store+ 2
Heating circ.
System 16
Boiler+ Heating circ.
System 17
Boiler+ Compressor+
Load. pump
System 18
Boiler+ Sol
a
S1 Storage Solar (bottom) Storage Solar (bottom) Storage Sol
a
S2 Storage HC (middle) Storage HC (middle)
S3 Storage Hot water (top) Storage Hot water (top) Storage Hot water (top) Storage Hot water (top) Storage Hot water (top) Storage Hot water (top) Storage Hot
S4 Flow HC2
S5 Flow HC1 Flow HC1 Flow HC1 Flow HC1 Flow HC1 Flow HC1 Flow HC1
S6 Burner Burner
S7 Outdoor Outdoor Outdoor Outdoor Outdoor Outdoor Outdoor
S8 Collector Collector Collector
VFS1
VFS2
V1
V2
R1
(ELR)
Solar pump Solar pump Solar pump
R2
(ELR)
Load. pump Boiler pump Load. pump Boiler pump
R3 Heating pump 2 Hot water-pump Hot water pump Hot water-p
u
R4 Mixer Open Mixer Open Mixer Open Mixer Open Mixer Open Mixer Open Mixer Open
R5 Mixer Closed Mixer Closed Mixer Closed Mixer Closed Mixer Closed Mixer Closed Mixer Close
d
R6 Heating pump Heating pump Heating pump Heating pump 1 Heating pump Heating pump Heating pu
m
R7
(pot.
free)
Compressor Burner request Compressor Burner requ
e
V1
V2

13
a
r+ Burner
System 19
Puffer+ Boiler+ Heating
circ.
System 20
Puffer+ Boiler+ Com-
pressor
System 21
Puffer+ Boiler+ Solar+
Burner
System 22
2 mixed Heating circ.
System 23
2 mixed Heating circ.+
Compressor
System 24
2 mixed Heating circ.+
Solar+ Compressor
a
r (bottom) Storage Solar (bottom) Storage Solar (bottom)
Storage HC (middle) Storage HC (top) Storage HC (middle) Storage HC (middle) Storage HC (middle) Storage HC (middle)
water (top) Storage Hot water (top) Storage DHW (top) Storage Hot water (top) Storage DHW (top) Storage DHW (top) Storage DHW (top)
HC2 Flow HC2 Flow HC2 Flow
Flow HC1 HC1 Flow Flow HC1 HC1 Flow HC1 Flow HC1 Flow
Burner
Outdoor Outdoor Outdoor Outdoor Outdoor Outdoor
Collector Collector
Load pump Solar pump Heating pump 1 Heating pump 1 Heating pump 1
DHW-Pump Boiler pump Heating pump 2 Heating pump 2 Heating pump 2
u
mp Hot water-pump Mixer Open Hot water-pump Mixer 1 Open Mixer 1 Open Mixer 1 Open
Mixer Open Mixer Closed Mixer Open Mixer 1 Closed Mixer 1 Closed Mixer 1 Closed
d
Mixer Closed Heating pump Mixer Closed Mixer 2 Open Mixer 2 Open Mixer 2 Open
m
p Heating pump Compressor Heating pump Mixer 2 closed Mixer 2 closed Mixer 2 closed
e
st Burner request Verdichter Burner
Signal Solar pump

14
Installation
The remote adjuster with integrated thermostat RC21 provides you with easy to use temperature controlled adjust-
ment of heating from within your living space.
Settings
The dial is used to parallel translate the heating curve. The flow temperature (still regarding the outdoor tempera-
ture) is raised or lowered respectively by your adjustement. When the dial is turned all the way down, the heating
circuit is switched off. Frost protection stays active to prevent damage.
Sensor
The RC21 contains a temperature sensor which is used by the controller.
If the settings in the controller permit it, the sensor is used to alter the flow temperature.
The switch changes the operation mode of the controller.
In Timer mode the temperature is controlled according to the set thermostat periods.
In Continous day mode the set periods are ignored and the temperature is controlled according to the day
time settings.
In Continous night mode the temperature is usually set to lowest. This setting is best suited for periods of
long absence like e.g. holidays.
Installation
Carefully remove the dial from the housing with a screwdriver.
Loosen the screw beneath. Remove the white part of the housing from the black socket.
The RC21 is connected via terminal block to the controller.
Remote adjuster (grey)
Room temperature sensor (green)
Sensor earth (white)
The RC21 is suited for low voltage only!
D.4. - RC 21 Room thermostat and remote adjuster
Caution
RC21 is an optional accessory and not included in the scope of supply by default.
The Latento System Controller is fully operational without the RC21.
Danger!

15
Operation
Examples of display symbols:
Pump (rotates in operation)
Valve (direction of flow in black)
Collector
Storage/Buffer
Hot water storage
Heating
Temperature sensor
Heat exchanger
Warning / Error message
New information available
Logging is active
More symbols can be found in
the chapter „Special functions“
(1)
(2)
(3)
(4)
The display (1), with its extensive text and graphics mode, is almost self-explanato-
ry, allowing easy operation of the controller.
To change from the overview to the settings menu, press the „esc“ key.
The green status LED (2) lights up when a relay is active, the red LED blinks when
an error occurs.
Inputs are made with 4 buttons (3+4), the functions of which change depending on
context.
The „esc“ key (3) is always used to cancel or exit a menu.
If applicable there will be a request for confirmation as to whether the changes
which have been made should be saved.
The function of each of the other three keys (4) is shown in the display line directly
above the keys; the right-hand key generally has a confirmation and selection func-
tion.
Examples of key functions:
+/- = increase/decrease values
/= scroll menu down/up
yes/no = approve/reject
Info = additional information
Back = to previous screen
ok = confirm selection
Confirm = confirm setting
E.1. - Display and input

16
Operation
Caution
Caution
Additional functions are not configured during the commissioning. If necessary, configure those after finishing
the commissioning.
Additional functions are not configured during the commissioning. If necessary, configure those after finishing
the commissioning.
If you decide not to use the commissioning help, you should make the necessary settings in the following sequence:
- Menu „10. - Language“ on page 54
- Menu „3.10. - Time and Date“ on page 21
- Menu „7.1. - Program selection“ on page 32
- Menu„5. - Settings“ on page 23, all values
- Menu „6. - Protective functions“ on page 28, if necessary
- Menu „7. - Special functions“ on page 32, if necessary,
Finally, menu „4.2. - Manual“ on page 22 should be used to test the switch outputs with the consumers connected, and to
check the sensor values for plausibility. Then switch on automatic mode.
E.2. - Commissioning help
The first time the controller is switched on and after the language and time have
been set, a query appears as to whether you want to parametrise the controller
using the commissioning help or not. The commissioning help can also be termi-
nated or called up again at any time in the special functions menu. The commis-
sioning help guides you through the necessary basic settings in the correct order,
and provides brief descriptions of each parameter in the display.
Pressing the “esc” key takes you back to the previous value so you can look at the
selected setting again or adjust it if desired. Pressing the “esc“ more than once
takes you back step by step to the selection mode, thus cancelling the commis-
sioning help. Finally, menu „4.2. - Manual“ on page 22 should be used to test
the switch outputs with the consumers connected, and to check the sensor values
for plausibility. Then switch on automatic mode.
Caution
Caution
Observe the explanations for the the individual parameters on the following pages, and check whether further
settings are necessary for your application.
Observe the explanations for the the individual parameters on the following pages, and check whether further
settings are necessary for your application.
E.3. - Free commissioning

17
Operation
Set Operating times, Time and Date
E.4 Menu sequence and menu structure
The graphics or overview mode appears when no key has been pressed for 2
minutes, or when the main menu is exited by pressing “esc“.
The up and down buttons are used to scroll through the list of sensors and relays
.
You can enter the Main menu by pressing the „esc“ key. The following menus are
available:
Current temperature values with explanations
Function control of the system with operating hours, etc.
Automatic mode, manual mode or switch unit off
Set parameters needed for normal operation
Solar and frost protection, recooling, anti-seizing protection
Program selection, sensor calibration, clock, additional sensor, etc.
Against unintentional setting changes
For diagnosis in the event of an error
Language selection
1. Measurements
2. Statistics
3. Periods
3. Operating mode
4. Settings
5. Protections
6. Special functions
7. Menu lock
8. Service Data
9. Language

18
Caution
The menu “1. Measurement values” serves to display the currently measured
temperatures.
The menu is closed by pressing “esc” or selecting “Exit measurement values”.
If “Error” appears on the display instead of the measurement value, then there may be a defective or incorrect
temperature sensor. If the cables are too long or the sensors are not placed optimally, the result may be small
deviations in the measurement values. In this case the display values can be compensated for by making en-
tries on the controller. Follow the instructions under „7.4. - Sensor calibration“ on page 52.
What measurement values are displayed depends on the selected program, the connected sensors and the
specific device design.
Measurement values
1. - Measurement values

19
2. - Statistics
Caution
The menu “2. Statistics” is used for function control and long-term monitoring of
the system.
The menu is closed by pressing “esc” or selecting “Exit statistics”.
For analysis of the system data it is essential for the time to be set accurately on the controller. Please note that
the clock continues to run for 24 hours if the mains voltage is interrupted, and must be reset afterwards. Im-
proper operation or an incorrect time may result in data being deleted, recorded incorrectly or overwritten.
The manufacturer accepts no liability for the recorded data!
Statistics
2.1. - Today
Temperature diagram of the past 24 hours
In the graphical overview the characteristics of outdoor-, flow- etc.temperature for the present day is shown from 0-24h. The
button on the right changes the unit of time and the two buttons on the left scroll through the diagram.
2.2. - 28 days
Flow temperature during the last 28 days
In the graphical overview the characteristics of e.g. the outdoor and flow temperature during the last 28 days are shown. The
right button changes the unit of time (Days) and the two left buttons scroll through the diagram.
2.3. - Operating hours
Display of operating hours of the relays; various time ranges (day-year) are available.
2.4. - Heat quantity
Displays the heat quantity of the system
2.5. - Graphic overview
This provides a clearly-organised display of the data listed above as a bar graph. Various time ranges are available for com-
parison. The two left-hand side keys can be used to scroll through the data.
2.6. - Message log
Display of the last 20 events occurring in the system with indication of date and time.
Resetting and deleting the individual analyses. The function “All statistics” clears all analyses but not the error messages.
2.7. - Reset/clear

20
3. - Periods
Periods
Caution
Menu “3. Times” is used to set the time, date, operating times for e.g. the heating
circuit and hot water.
The menu is closed by pressing “esc” or selecting “Exit periods”.
The associated temperature reference values are specified in menu 5 “Set-
tings”!
3.1. - Heating circuit day
This menu is used to select the daytime mode times for the heating circuit; three time periods can be specified for each weekday
and copied to other days.
Setting range: Three time ranges for each day of the week
Default: Mo-Su 6:00-22:00
Note: See 5. for the associated temperature settings
Caution
Times that are not specified are automatically considered to be nighttime mode. The set times are only taken
into account in the heating circuit operating mode “Automatic”
3.2. - Heating circuit 2 day
This menu is used to select the daytime mode times for the second heating circuit; three time periods can be specified for each
weekday and copied to other days.
Setting range: Three time ranges for each day of the week
Default: Mo-Su 6:00-22:00
Note: See 5. for the associated temperature settings
Caution
Times that are not specified are automatically considered to be nighttime mode. The set times are only taken
into account in the heating circuit operating mode “Automatic”
3.3. - Heating comfort
This menu can be used to select a time range for each day of the week in which the heating circuit is supplied with an in-
creased comfort temperature, e.g. for quick heating in the morning.
Setting range: One time range for each day of the week
Default: Mo-Su off
Note: See 5. for the associated temperature settings.
3.4. - Heating circuit 2 comfort
This menu can be used to select a time range for each day of the week in which the second heating circuit is supplied with an
increased comfort temperature, e.g. for quick heating in the morning.
Setting range: One time range for each day of the week
Default: Mo-Su off
Note: See 5. for the associated temperature settings.
Caution
Times that are not specified are set to “disabled”.
3.5. - Hot water enable
This menu is used to select the times when the domestic hot water heating is enabled (sensor 3); three time periods can be
specified for each weekday and copied over to the following days.
Setting range: Three time ranges for each day of the week
Default: Mo-Su 6:00-22:00
Note: See 11. for the associated temperature settings
Table of contents
Other Würth Controllers manuals