Tech Controllers EU-28N User manual

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EU-28N

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TABLE OF CONTENTS
1Safety .......................................................................................................................................................................................... 4
2Device description....................................................................................................................................................................... 5
3Installing the Controller .............................................................................................................................................................. 5
4Controller operation ................................................................................................................................................................... 7
5Controller functions –Main Menu.............................................................................................................................................. 7
5.1 Firing up/ Extinguishing..................................................................................................................................................... 8
5.2 Screen view ....................................................................................................................................................................... 8
5.3 Temperature settings ........................................................................................................................................................ 8
5.3.1 CH set temperature....................................................................................................................................................... 8
5.3.2 DHW set temperature................................................................................................................................................... 8
5.4Work setting...................................................................................................................................................................... 8
5.4.1 Blowing force ................................................................................................................................................................ 8
5.4.2 Fan in maintaining......................................................................................................................................................... 8
5.4.3 Maintaining time........................................................................................................................................................... 8
5.4.4 Fan speed in maintaining .............................................................................................................................................. 9
5.5 Manual operation.............................................................................................................................................................. 9
5.6 Pump operating mode....................................................................................................................................................... 9
5.6.1 Heating.......................................................................................................................................................................... 9
5.6.2 Boiler priority ................................................................................................................................................................ 9
5.6.3 Parallel pumps............................................................................................................................................................... 9
5.6.4 Summer mode............................................................................................................................................................... 9
5.7 Time settings ................................................................................................................................................................... 10
5.8 Date settings.................................................................................................................................................................... 10
5.9 Weekly schedule control ................................................................................................................................................. 10
5.10 Installer menu.................................................................................................................................................................. 11
5.11 Service menu................................................................................................................................................................... 11
5.12 Language selection .......................................................................................................................................................... 11
5.13 Factory settings ............................................................................................................................................................... 11
5.14 Software version.............................................................................................................................................................. 11
6Controller functions –Installer Menu....................................................................................................................................... 12
6.1 Reduction by the room controller................................................................................................................................... 12
6.2 Room controller............................................................................................................................................................... 12
6.2.1 CH pump control ......................................................................................................................................................... 12
6.2.2 Boiler control............................................................................................................................................................... 12
6.3 Pump switch-on temperature ......................................................................................................................................... 13
6.4 DHW hysteresis ............................................................................................................................................................... 13
6.5 Disinfection of the boiler................................................................................................................................................. 13
6.6 Anti-stop for pumps ........................................................................................................................................................ 13

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6.7 Antifreeze temperature................................................................................................................................................... 13
6.8 Boiler hysteresis .............................................................................................................................................................. 14
6.9 Screen setup.................................................................................................................................................................... 14
6.10 Display contrast............................................................................................................................................................... 14
6.11 Factory settings ............................................................................................................................................................... 14
7Protections................................................................................................................................................................................ 14
7.1 Temperature alert ........................................................................................................................................................... 14
7.2 Thermal protection.......................................................................................................................................................... 14
7.3 Automatic sensor control................................................................................................................................................ 15
7.4 Boiler boiling water protection ....................................................................................................................................... 15
7.5 Temperature protection.................................................................................................................................................. 15
7.6 Fuse ................................................................................................................................................................................. 15
8Technical specifications ............................................................................................................................................................ 15
PS, 02.02.2023
ALL IMAGES PUBLISHED SERVE ILLUSTRATION ONLY AND MAY DIFFER FROM THE ACTUAL APPEARANCE.
EU DECLARATION OF CONFORMITY
Hereby, we declare under our sole responsibility that EU-28N manufactured by TECH STEROWNIKI, head-quartered in
Wieprz Biała Droga 31, 34-122 Wieprz, is compliant with Directive 2014/35/EU of the European Parliament and of the
Council of 26 February 2014 on the harmonisation of the laws of Member States relating to the making available on
the market of electrical equipment designed for use within certain voltage limits (EU OJ L 96, of 29.03.2014, p. 357),
Directive 2014/30/EU of the European Parliament and of the Council of 26 February 2014 on the harmonisation of the
laws of Member States relating to electromagnetic compatibility (EU OJ L 96 of 29.03.2014, p.79), Directive
2009/125/EC establishing a framework for the setting of ecodesign requirements for energy-related products as well
as the regulation by the MINISTRY OF ENTREPRENEURSHIP AND TECHNOLOGY of 24 June 2019 amending the regulation
concerning the essential requirements as regards the restriction of the use of certain hazardous substances in electrical
and electronic equipment, implementing provisions of Directive (EU) 2017/2102 of the European Parliament and of
the Council of 15 November 2017 amending Directive 2011/65/EU on the restriction of the use of certain hazardous
substances in electrical and electronic equipment (OJ L 305, 21.11.2017, p. 8).
For compliance assessment, harmonized standards were used:
PN-EN IEC 60730-2-9:2019-06,
PN-EN 60730-1:2016-10,
EN IEC 63000:2018 RoHS.
Wieprz, 02.02.2023

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1SAFETY
Before operating the device please read the following instructions carefully. Failure to observe these instructions may cause
personal injuries and damage the device.
To avoid unnecessary errors and accidents, make sure that all persons operating the device are thoroughly familiarized with its
operation and safety functions. Please retain the operating manual for future reference and make sure that it stays with the device
if it is transferred or sold, so that everyone using it will have sufficient information concerning the operation and safety of the
device. For the safety of life and property, take precautions in accordance with the user manual, as the manufacturer is not
responsible for damage caused by negligence.
WARNING
•Live electrical equipment. Before carrying out any operations related to the power supply (connecting cables,
installing the device, etc.), make sure that the controller is not connected to the mains.
•Installation should be carried out by a person holding appropriate electrical qualifications.
•Before starting the controller, the ground resistance of electric motors and the insulation resistance of electric wires
should be measured.
•The controller is not intended to be operated by children.
CAUTION
•Atmospheric discharges can damage the controller, so during a thunderstorm, switch it off by unplugging the mains
plug.
•The controller may not be used contrary to its intended purpose.
•Before and during the heating season, check the technical condition of the cables. Also check the installation of the
controller, clean dust and other soiling.
There could be changes introduced in the products listed in the present manual, following its last revision of 02.02.2023. The
manufacturer reserves the right to introduce design changes. Illustrations may contain optional equipment. Printing technology
may affect differences in the presented colours.
Care for the natural environment is of paramount importance to us. The awareness that we
manufacture electronic devices is linked with our obligation to dispose the used electronic parts
and devices in a way that is safe for the environment. Therefore, the company received a
registration number issued by the Polish Chief Inspector for Environmental Protection. The symbol
of the crossed wheeled bin on the product indicates that the product must not be disposed of with
municipal waste. By segregating waste for recycling, we help protect the environment. It remains
the user's responsibility to hand over used equipment to a designated collection point for recycling
electrical and electronic equipment waste.

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2DEVICE DESCRIPTION
The EU-28N controller is designed for CH boilers. It controls the CH water circulation pump, DHW domestic hot water pump
and blowing (fan). If the boiler temperature is lower than the set temperature, the controller is in the operating cycle, in which
the blower operates at all times.
If the boiler temperature is equal to or higher than the set temperature, then the controller is in the temperature maintaining
cycle, and the controller works by switching on the purges at a frequency depending on the user's settings. The duration of
operation and interruptions of purges in the maintaining cycle should be selected according to the type of fuel burned in the
boiler.
CAUTION
Each controller must be set individually, depending on the type of fuel used in the boiler, and also the type of boiler. TECH
is not responsible for incorrect controller settings.
In case of voltage loss, the thermoregulator will stop working. After the power supply is reconnected, the controller returns to
operation with previously set parameters thanks to its built-in memory. Lack of power supply does not delete the stored
thermoregulator parameters.
3INSTALLING THE CONTROLLER
The controller should be installed by a properly qualified person only.
WARNING
Danger of injury or death due to electric shock on live connections. Before working on the controller, disconnect its power
supply and secure it against accidental switching on.
CAUTION
Incorrect wiring may damage the controller.

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In the back of the controller there are connectors to which sensors and devices operated by the controller should be connected:

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4CONTROLLER OPERATION
1. UP button - changes the set temperature from the main screen view, after entering the controller menu, this
button is used to increase the operating settings.
2. DOWN button - changes the set temperature from the main screen view, after entering the controller menu,
this button is used to reduce the operating settings.
3. Entering the controller menu, confirming the settings.
4. Power switch.
5. Exit from the controller menu, cancel settings.
5CONTROLLER FUNCTIONS –MAIN MENU
MAIN
MENU
Firing up/ Extinguishing
Screen view
Temperature settings
Work setting
Manual operation
Pump operating mode
Time settings
Date settings
Weekly schedule control
Installer menu
Service menu
Language selection
Factory settings
Software version
1
2
3
4
5

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5.1 FIRING UP/EXTINGUISHING
After the initial ignition of the boiler, the Ignition function must be activated. In this mode, the fan will start working to facilitate
ignition (in a still cold boiler). Once the CH temperature rises to 30°C (the so-called fan threshold), the Fan On/ Off function will
appear on the display instead of the Ignition option and the Manual Operation diode will turn off and the boiler will enter the
operating mode. Using the Fan On/ Off function, the fan can be switched on or off (e.g. when adding fuel). Turning off the fan is
indicated by an asterisk on the main screen in the lower right corner of the display. This function allows for safe operation of the
boiler. Never open the furnace door with the fan on. If the boiler reaches a temperature of 35°C, the pump (or both pumps
depending on the operating mode) will start.
5.2 SCREEN VIEW
In this function, the user can select one of the available main screens of the thermoregulator operation. These are:
•CH screen (the current boiler operating mode is displayed)
•Service screen (allows you to view the parameters available in the service menu)
5.3 TEMPERATURE SETTINGS
5.3.1 CH SET TEMPERATURE
This option is used to set the boiler temperature. The user can change the boiler temperature range from 40OC to 80OC. The set
CH can also be changed directly from the main screen of the controller.
5.3.2 DHW SET TEMPERATURE
This option is used to set the set temperature of domestic hot water. The user can adjust this temperature in the range from 35OC
to 60OC.
5.4 WORK SETTING
MAIN
MENU
WORK
SETTING
Blowing force
Fan in maintaining
Maintaining time
Fan speed in maintaining
5.4.1 BLOWING FORCE
This function controls the fan speed. The adjustment range is from 1 to 100%, (it can be assumed that these are fan speeds). The
higher the speed, the faster the fan works, where 1% is the minimum fan speed and 100% is the maximum.
5.4.2 FAN IN MAINTAINING
In this function, the user sets the running time and the fan pause time during the operation in the temperature maintaining cycle.
5.4.3 MAINTAINING TIME
This option is used to set the fan idle time during the maintaining period.
CAUTION
Incorrect setting of this option may cause a constant increase in temperature! The maintaining interval should not be
too short.

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5.4.4 FAN SPEED IN MAINTAINING
This option allows you to select the appropriate fan speed (blowing power) in maintaining cycle.
5.5 MANUAL OPERATION
For the convenience of the user, the controller has been equipped with a Manual Operation module. In this function, each
actuator (fan, CH pump, DHW pump) is switched on and off independently of the others.
Pressing the OPTIONS button starts the motor of the selected device. This device remains running until the OPTIONS button is
pressed again.
The blowing speed option is also available, enabling the user to set any fan speed in manual operation.
5.6 PUMP OPERATING MODE
In this function, the user selects one of the available boiler operation modes.
MAIN
MENU
OPERATING
MODE
Heating
Boiler priority
Parallel pumps
Summer mode
5.6.1 HEATING
After selecting this option, the controller enters the "only heating" state. The CH pump will start operating above the CH pump
start-up temperature. Below this temperature (minus the hysteresis value) the pump stops working.
5.6.2 BOILER PRIORITY
In this mode, the DHW pump operates until the boiler is heated (the valves close to the maximum and the valve pumps are
switched off). At the moment of obtaining the set temperature on the boiler, the previously operating pump will be switched off,
while the CH pump will be switched on and the mixing valves will be switched on. The moment the boiler temperature drops
below the set point temperature by the hysteresis value, the DHW pump will switch on again and the valves will stop working.
CAUTION
The boiler should have check valves installed in the CH and DHW pump circuits. The valve mounted on the DHW pump
prevents the extraction of hot water from the boiler. The valve mounted on the circuit of the CH pump does not let the
hot water that heats the boiler to the home heating system.
5.6.3 PARALLEL PUMPS
Mode in which the CH pump operates above the pump start-up threshold. The DHW pump switches on in parallel and reheats the
boiler, while after reheating the DHW, the pump switches off. The pump will restart after the temperature drops by the DHW
hysteresis value.
CAUTION
If the boiler's current temperature is lower than the current temperature on the boiler, the DHW pump will not switch
on to protect against cooling of the boiler water.
5.6.4 SUMMER MODE
When this function is activated, the CH pump is switched off and the DHW pump is switched on above the pump switch-on
threshold. When the threshold temperature is exceeded, the DHW pump operates all the time until the boiler temperature drops
below the pump start-up threshold (by DHW hysteresis value). In the summer function, only the set temperature of the DHW
vessel is set, which is also the set temperature of the boiler.

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5.7 TIME SETTINGS
Time settings are used to set the current time.
5.8 DATE SETTINGS
Used to set the current date.
5.9 WEEKLY SCHEDULE CONTROL
The function allows you to program deviations of the boiler set temperature (submenu Boiler week) on individual days of the week
at specific times.
CAUTION
For the correct operation of this function it is necessary to set the current date and time.
To enable weekly control, select and check Mode 1 or Mode 2. Detailed settings of these modes can be found in the following
sections of the submenu: Set Mode 1 and Set Mode 2.
When one of the modes is activated, a digit with the value of the currently set deviation will be displayed on the main page of the
controller, below the set temperature (alternatively with the inscription Set) (at the same time informing about the active weekly
control).
Changing weekly control settings:
In the EU-28N controller, you can program the weekly control in two different modes:
MODE 1 - in this mode it is possible to program deviations of the set temperature for each day of the week separately.
MODE 2 –in this mode, the user programs temperature deviations for weekdays (Monday –Friday) and for the weekend (Saturday
–Sunday).
Mode 1 programming:
To program mode 1, the user starts the Set mode 1 parameter –a screen with individual days of the week appears on the display.
After selecting the day of the week the settings of which we wish to change, the edit screen appears: the current deviation setting
is displayed in the upper line and the lower displays the time interval. Use the UP/DOWN buttons to navigate to the next time
frame. To edit a setting, click OPTIONS, and then click Change.
To copy the settings for the subsequent hours, set the parameter, and then select the Copy function.
Example
Monday
settings: 3 00, temp -100C (weekly control setting: –100C)
settings: 4 00, temp -100C (weekly control setting: –100C)
settings: 5 00, temp -100C (weekly control setting: –100C)
In this case, if the setpoint temperature on the boiler is 600C, then from 300 hours on Monday to 600 hours the setpoint temperature
on the boiler will drop by 100C, i.e. it will be 500C.
Mode 2 programming:
To program mode 2, the user starts the Set mode 2 parameter –the display shows a screen with two intervals for days of the
week: Monday –Friday and Saturday - Sunday. After selecting the interval that we want to change, we go to their editing –a
procedure such as in the mode 1 programming.
Example
Monday-Friday
settings: 3 00, temp -100C (weekly control setting: –100C)
settings: 4 00, temp -100C (weekly control setting: –100C)

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settings: 5 00, temp -100C (weekly control setting: –100C)
Saturday-Sunday
settings: 16 00 , temp 50C (weekly control setting: +50C)
settings: 1700 , temp 50C (weekly control setting: +50C)
settings: 1800 , temp 50C (weekly control setting: +50C)
In this case, if the setpoint temperature on the boiler is 600C, then from 300 hours to 600 hours from Monday to Friday the setpoint
temperature on the boiler will drop by 100C, i.e. it will be 500C. On the other hand, during the weekend (Saturday, Sunday) from
1600 to 1900, the set temperature on the boiler will increase by 50C, i.e. it will be 650C.
5.10 INSTALLER MENU
The installer menu is intended for use by people with appropriate qualifications and is mainly used for setting additional controller
functions. Detailed parameters found in the Installer Menu are described later in the manual.
5.11 SERVICE MENU
To enter the service functions of the EU-28N controller, enter the four-digit code. This code is owned by Tech.
5.12 LANGUAGE SELECTION
Function that enables the user to select their preferred language version. This change is also possible using the flag button located
on the controller.
5.13 FACTORY SETTINGS
The controller is pre-configured for operation. However, it needs to be adapted to the needs of the user. It is possible to return to
the factory settings at any time. By enabling the factory settings options, all the boiler's own settings (stored in the user menu)
are deleted and the manufacturer's settings are restored. From now on, you can set your own boiler parameters again.
5.14 SOFTWARE VERSION
The option allows you to view the controller software version number –this information is necessary when contacting the service
technician.

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6CONTROLLER FUNCTIONS –INSTALLER MENU
The installer menu is intended for use by suitably qualified persons and is mainly used for setting additional controller functions
such as boiler parameters, additional valves, additional pumps, etc., and for adjusting the basic functions in detail.
6.1 REDUCTION BY THE ROOM CONTROLLER
In this function, set the value by which the controller will lower the set CH temperature when the temperature set for the room
controller is reached (room heated).
6.2 ROOM CONTROLLER
INSTALLER
MENU
ROOM
CONTROLER
CH pump control
Boiler control
This function allows to indicate the type of controller connected to the EU-28N controller, and to program the operation of the
room controller.
6.2.1 CH PUMP CONTROL
The function enables activation of the control of the room regulator over the operation of the CH pump After activation of this
function, the CH pump will be switched off when the room regulator reports reaching the heating temperature of the room.
•Standard regulator –check this option if the valve is to be controlled by a two-state room regulator.
6.2.2 BOILER CONTROL
The room controller will reduce the value of the boiler setpoint by the parameter Reduction by room controller in the Installer
menu.
•Standard regulator –check this option if the valve is to be controlled by a two-state room regulator.
INSTALLER
MENU
Reduction by the room controller
Room controller
Pump switch-on temperature
DHW hysteresis
Disinfection of the boiler
Anti-stop for pumps
Antifreeze temperature
Boiler hysteresis
Screen setup
Display contrast
Factory settings

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6.3 PUMP SWITCH-ON TEMPERATURE
This option is used to set the switch-on temperature of the pumps (this is the temperature measured on the boiler). Below the
set temperature, the pumps do not operate, and above this temperature, the pumps are switched on, but operate depending on
the mode of operation.
6.4 DHW HYSTERESIS
This option is used to set the boiler set point hysteresis. This is the difference between the set temperature (i.e. the desired
temperature on the boiler) and the return to operation temperature (for example: when the set temperature is 55°C and
hysteresis is 5°C, then once the set temperature is reached, i.e. 55°C, the DHW pump switches off. The DHW pump will be switched
on again after the temperature has dropped to 50°C).
Example:
DHW set temperature
55°C
Hysteresis
5°C
Pump shutdown
55°C
Switching the pump on again
50°C
When the preset temperature is 55°C and the hysteresis is 5°C, the device will be switched off when the temperature
reaches 55°C, while the return to the operating cycle will occur when the temperature drops to 50°C).
6.5 DISINFECTION OF THE BOILER
Thermal disinfection consists in raising the temperature to the required disinfection temperature of min. 60°C it the entire DHW
circuit. The new regulations impose the obligation to adapt the DHW installation to periodic thermal disinfection carried out at a
water temperature not lower than 60°C (the recommended temperature is 70°). Wires, fittings and technological system of hot
water preparation must meet this condition.
Disinfection of DHW is aimed at eliminating Legionella pneumophila bacteria, which cause a decrease in the cellular immunity of
the body. This bacterium often multiplies in vessels with standing hot water (optimum temperature 35°C), which often takes place,
for example, in boilers.
When this function is activated (only possible in Boiler Priority mode), the boiler heats up to 70°C (factory setting) and maintains
this temperature for 10 minutes (factory setting) and then returns to normal operation mode.
From the moment of disinfection, the temperature of 70°C must be reached for not more than 60 minutes (factory setting),
otherwise this function will automatically deactivate.
6.6 ANTI-STOP FOR PUMPS
After enabling this option, the pump will switch on depending on the user's settings every 1-20 days for a set time (min. 30, max.
180 seconds). This prevents water from fouling the installation outside the heating season.
6.7 ANTIFREEZE TEMPERATURE
This option allows you to enable the antifreeze function, which is designed to protect the installation against freezing. After the
temperature on the boiler or tank sensor drops below the specified value, the pump is switched on permanently. Its shutdown
will only occur once the temperature in the circuit rises.

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6.8 BOILER HYSTERESIS
This option is used to set the hysteresis of the set CH temperature. This is the difference between the temperature of entry into
the temperature maintaining cycle and the temperature of return to the operating cycle (e.g. when the set temperature is 60°C
and the hysteresis is 3°C, the transition to the maintaining cycle will occur after the temperature is reached 60°C, while the return
to the operating cycle will occur after the temperature drops to 57°C).
6.9 SCREEN SETUP
The option allows the user to set screen parameters such as: screen brightness, screen fading and fading time according to their
needs and preferences.
6.10 DISPLAY CONTRAST
This function allows you to change the contrast settings of the display.
6.11 FACTORY SETTINGS
The controller is delivered pre-configured for operation. However, it needs to be adapted to the needs of the user. It is possible
to return to the factory settings at any time. Enabling the factory defaults option will delete all user settings of the boiler (as stored
in the user menu), replacing them with default values set by the boiler manufacturer. From now on, you can set your own boiler
parameters again.
7PROTECTIONS
In order to ensure maximally safe and seamless operation, the controller has a number of safeguards. In the event of an alarm, an
acoustic signal is activated and a message will appear on the display.
7.1 TEMPERATURE ALERT
This protection is activated only in the operating mode (if the boiler temperature is lower than the set temperature). If the boiler
temperature failed to rise within the time specified by the user, this alert is triggered, the blower is switched off and an acoustic
signal is activated. The following message is displayed on the display: “Temperature is not rising”. Pressing the OPTIONS button
will disable this alert. The controller will return to the last set operating mode.
7.2 THERMAL PROTECTION
It is an additional mini bimetallic sensor (located next to the boiler temperature sensor –or on the supply pipe as close as possible
to the boiler), disconnecting the fan in case of exceeding the alarm temperature –about 85÷90OC. Its operation prevents boiling
of water in the installation, in case of overheating of the boiler or damage to the controller. When this protection is activated,
once the temperature drops to a safe value, the sensor will unlock itself. If this sensor is damaged or overheated, the fan will be
disconnected.
CAUTION
In the event of damage to the thermal switch, the fan will not work both in manual operation and in automatic operation
mode.

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7.3 AUTOMATIC SENSOR CONTROL
If the CH, DHW or screw temperature sensor or fuel reservoir is damaged, an audible alarm is activated, additionally signalling the
relevant fault on the display, e.g.: "CH sensor damaged". The blower is switched off. The pump operates independently of the
current temperature.
7.4 BOILER BOILING WATER PROTECTION
This protection applies only to the boiler priority operating mode, in case the tank is underheated. Namely, when the boiler
temperature is set, e.g.: 55OC, and the actual temperature on the boiler rises to 62OC (this is the so-called priority temperature),
then the controller turns off the fan. If the temperature on the boiler rises to 80OC, the CH pump will switch on. When the
temperature continues to rise, an alarm will sound at 85OC. Most often, such a state can occur when the boiler is damaged, the
sensor is incorrectly fixed, or the pump is damaged. However, once the temperature decreases, at the 60OC threshold, the
controller will turn on the blower and will operate in the operating mode until the temperature reaches 62OC.
7.5 TEMPERATURE PROTECTION
The controller has additional mechanical protection against dangerous temperature increase. If the alarm temperature (80OC) is
exceeded, the fan is disconnected. When the temperature of 85OC is exceeded, an alarm is activated and a message appears on
the display reading: "Temperature too high". Once the temperature drops to a safe value, after pressing the OPTIONS button, the
alarm will be turned off and the controller will return to the last set operating mode.
7.6 FUSE
The controller has a 3.15A WT glass tube fuse insert, which protects the network.
CAUTION:
Using a higher rating fuse may cause damage to the controller.
8TECHNICAL SPECIFICATIONS
In the EU-28N controller, one should check the technical condition of the wiring before and during the heating season. Also check
the mounting of the controller, clean it from dust and soiling, and measure the grounding of the motors (CH pump, DHW pump,
blower).
No.
Specification
1
Power supply
230V ±10% /50Hz
2
Max. power consumption
4.5W
3
Operation temperature
5÷50°C
4
Pump max. output load
0.5A
5
Fan max. output load
0.6A
6
Temperature measurement accuracy
±1°C
7
KTY sensor thermal resistance
-30÷99°C
8
Fuse
2x 3.15A

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