Tech Controllers EU-i-2 Plus OT User Manual page 19


Hysteresis – the hysteresis between the pre-set temperature and current valve temperature.

Single stroke - This is a maximum single stroke (opening or closing) that the valve may make during one
temperature sampling. If the temperature is near the pre-set value, the stroke is calculated on the basis of
<proportionality coefficient> parameter value. The smaller the single stroke, the more precisely the set
temperature can be achieved. However, it takes longer for the set temperature to be reached.

Proportionality coefficient - Proportionality coefficient is used for defining valve stroke. The closer to the pre-
set temperature, the smaller the stroke. If the coefficient value is high, the valve takes less time to open but at
the same time the opening degree is less accurate. The following formula is used to calculate the percent of a
single opening:

Sensor calibration - this function enables the user to calibrate the built-in valve at any time. During this process
the valve is restored to its safe position – in the case of CH valve it is fully opened whereas in the case of floor
valve it is closed.

Opening in CH calibration – this function enables the user to change the direction of valve opening/closing
during calibration.

Weekly control - this function is described in section XIII.

Valve deactivation - once this has been selected, valve operation depends on weekly control settings and
external temperature.
 Weekly control - once this function has been selected, the user may activate/deactivate weekly
operation schedule and define the time when the valve will be closed.
 External temperature - the user may set nighttime and daytime temperature at which the valve will be
deactivated. It is also possible to program hours when the controller will operate in day or night mode.
The user sets the hysteresis of valve deactivation temperature.
NOTE
The function of Valve deactivation based on outside temperature does not work in cooling mode. The
Return protection type does not offer Valve deactivation function.

Protections
 Return protection - this function is used to set CH boiler protection against too cool water returning
from the main circuit, which could cause low-temperature boiler corrosion. The return protection
involves closing the valve when the temperature is too low, until the short circulation of the boiler
reaches appropriate temperature. The user may set the temperature threshold below which the return
protection will be activated.
NOTE
To ensure the effectiveness of this protection, it is necessary to activate the valve in the heating circuit menu
and connect the return
(PRE-SET_TEMP - SENSOR_TEMP) * (PROP_COEFF /10)
sensor.
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