TECH ST-408N User Manual

Tech

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ST-408N – user's manual

Declaration of Confirmity No. 86/2013

Hereby, we declare under sole responsibility that the ST-408N

230V 50Hz thermoregulator manufactured by TECH,

headquartered in Wieprz 1047A, 34-122 Wieprz, is compliant

with the Regulation by the Ministry of Economy. (Journal of

Laws Dz.U. 155 Item 1089) of July 21, 2007 implementing

provisions of the Low Voltage Directive (LVD) 2006/95/EC of

January 16, 2007.

The ST-408N controller has been tested for

electromagnetic compatibility (EMC) with optimal loads

applied.

For compliance assessment, harmonized standards were

used:

PN-EN 60730-2-9:2011, PN-EN 60730-1:2012.

Marked product CE: 04/2013.

Wieprz, 23 IV 2013

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Tech

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ST-408N – user's manual

I. Use

ST-408N thermoregulator is intended for controlling central heating installation.
The controller supports two mixing valves, DHW pump (of water boiler), circulating
pump and a solar collector. The controller may cooperate with two ST-61 modules,
which enables the user to control the total of five mixing valves. The controller
features weather control and weekly control functions and it may support three
two-state (standard) room regulators and one TECH regulator. The device has one
voltage contact (additional contact 1) and two dry contacts (additional contacts 2
and 3). It is also compatible with GSM module and Internet module.
Return temperature protection is another asset of the device. It prevents the
water in the short circulation from boiling and ensures that the temperature of
water returning to the CH boiler is not too low.

II.Principle of operation

Controller operation involves mixing the hot circulating water with the water
returning from the heating circuit in order to reach and maintain the set
temperature.
Pumps which are connected to each valve circuit help to distribute the water
throughout the system. A pump should be connected behind the mixing valve
whereas the temperature sensor should be placed behind both the pump and the
valve in order to ensure accurate measurement of the valve output temperature.
Note: if the valve controller and the CH boiler controller operate simultaneously in
one circuit, the pump may be connected from the CH boiler controller (the pump
output in the ST-408N regulator and in the additional module remains unconnected)

The device is controlled using a touch screen.

II.a) Main page

During normal operation, the graphic display of the regulator shows the main
page, which may differ depending on user's settings. The main screen shows the
following information:

• current and set temperatures of the active valves,

• current and set temperature of the water boiler

• current and set temperature of the buffer

• outdoor temperature

• time and day of the week

• operation mode of the pumps

The screen view shown above is the default one in ST-408N controllers. The user
may also switch to panel screen:

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III. Main menu

III.a) Valve 1

In this submenu the user may adjust the basic settings of the first valve.

III.a.1) Set temperature

This option is used to set the desired temperature which will be
maintained by the first valve. The temperature may be adjusted in the main screen,
when Temp 1 is active. During proper operation, the temperature of water behind
the valve be approaching the set temperature of the valve.

III.a.2) Activated

This option is used to activate valve 1. When the valve is turned off, the pump
is also inactive. After connecting the controller to the power source, the valve is
always calibrated, even if it is deactivated. It prevents the valve from remaining in
dangerous position.

III.a.3) Calibration of the valve

This function enables the user to calibrate the first valve at any time. During this
process the valve is restored to its safe position – in the case of CH valve it is fully

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ST-408N – user's manual

opened whereas in the case of floor valve it is closed.

III.b) Valve 2

In this submenu the user adjusts the basic parameters of the second valve similarly
as in the case of valve 1.

III.c) DHW pump (of the water boiler)

This function enables the user to adjust the parameters of DHW pump operation.

III.c.1) DHW set temperature

This function is used to adjust the set temperature of domestic water. It may be
done in the main screen of the controller when DHW view is active. After the water
in the water boiler reaches this temperature, the controller switches off the DHW
pump. The pump will be enabled again when the temperature drops below the set
value minus DHW hysteresis.

III.c.2) Operation modes

This function enables the user to switch off the DHW pump if it is not used, or
to activate automatic operation (the pump operates according to parameters
described in the following section).

III.c.3) DHW hysteresis

This option is used to set the hysteresis of the water boiler set temperature. It
is the difference between the set temperature (desired temp. of the water boiler)
and the temperature of returning to operation mode. For example, if the set
temperature is 55°C and the hysteresis value is 5 °C, the DHW pump is switched off
when the set temperature of 55°C is reached, and it is activated again when the
temperature drops to 50°C.

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III.c.4)DHW pump activation threshold

This option is used to set the temperature of DHW pump activation (it is the
temperature measured by the CH boiler sensor). When the temperature remains
below this value, the pump is inactive, whereas when the temperature is above this
value, the pump is switched on and works until the set temperature is reached.

III.c.5) Weekly control (of the DHW pump)

This function is used to program daily changes of the water boiler
temperature. The range of set temperature deviation is +/- 100C.

Weekly control is explained in detail in section IV.d.17.

III.c.6) Maximum temperature

This function is used to set the maximum DHW temperature. After it has been
reached, the DHW pump is switched off.

III.c.7) Sensor

This function enables the user to choose the sensor which will serve as the
DHW sensor.

III.d) Circulating pump

This function is used to control the pump which mixes hot water between the CH
boiler and DHW receivers. After activating this function the user sets the 24-hour
cycle of pump pause and activation (with the accuracy of 30 minutes).

In order to make setting the 24-hour cycle easier, the user may copy a
selected time interval into the next one. After the operation plan is defined, the user
sets the pump operation time and the pump pause time while the previously
selected time interval is active. The user may easily delete the previously saved
settings in order to introduce new intervals.

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ST-408N – user's manual

III.d) Operation modes

In this function the user may choose one of the three operation modes
available.

III.d.1) Water boiler priority

In this mode, the DHW pump is activated first and it operates until the set
DHW temperature is reached (the valves close completely and the valve pumps are
switched off). After the set temperature has been reached, the pump is switched off
and the mixing valves are activated (along with the pumps – according to their
settings).

The valves operate continuously until the water boiler temperature drops
below the set value minus hysteresis. Then, the valve pumps are switched off and
the DHW pump is switched on.

III.d.2) Parallel pumps

In this mode, all active pumps and valves operate simultaneously. The valves
maintain the set temperature and the water boiler is heated to the set temperature.

III.d.3) Summer mode

In this mode, the CH valves are closed to prevent unnecessary house heating. In the
case when the CH boiler temperature is too high, the valve will b e opened as an
emergency procedure (requires activation of return protection!)

In this mode the water boiler pump and the floor valves operate normally
according to their settings.

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III.e) Manual mode

When the manual mode option is selected, the user can open and close the
valves (and the auxiliary valves if they are active) manually. It is also possible to
switch on/off each valve pump, DHW pump, circulating pump as well as the
additional contacts in order to check if the device works properly.

III.f) Time

Time option enables the user to set the current time and day of the week.
Setting the time is essential for weekly control to operate correctly.

III.g) Fitter's menu

The following sections provide detailed information on all functions which are
available in the fitter's menu.

III.e) Screen

After selecting Screen option, the user may customize the main screen
settings.

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