ST-979 user’s manual
17
VI.a.5)
Weather-based control
For the function of weather control to be active, the external sensor mustn't be exposed to sunlight
or influenced by the weather conditions. After it is installed in an appropriate place, weather
control function needs to be activated in the controller menu.
For the valve to operate correctly, the user defines the pre-set temperature (behind the valve)
for 4 intermediate external temperatures:-20ºC, -10ºC, 0ºC and 10ºC.
The user selects external temperature value using LEFT and RIGHT arrows and defines a
corresponding pre-set temperature value using DOWN and UP arrows. Subsequently, the display
shows the heating curve.
Heating curve – it is a curve according to which the pre-set controller
temperature is determined, on the basis of external temperature. In our controller, this curve is
constructed on the basis of four pre-set temperatures for respective values of external
temperatures.
The more points constructing the curve, the greater its accuracy, which allows its flexible shaping.
In our opinion, four points seem a very good compromise ensuring decent accuracy and easiness
of setting the course of this curve.
VI.a.6)
Valve pump
This option enables the user to select the working mode of the pump out of the following:
always ON - the pump operates all the time, regardless of temperatures,
always OFF- the pump is permanently deactivated and the regulator controls only the
valve operation,
ON above the threshold - the pump is activated above the pre-set switch on
temperature.
If the pump is to be activated above the threshold, the user should also
define the threshold temperature of pump activation.
VI.a.7)
Return protection
This function enables the user to set boiler protection against too cool water returning from the
main circulation, 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 the appropriate temperature. Once activated, the user presets the minimum acceptable
return temperature.
VI.a.8)
CH boiler protection
NOTE
Function available only for a built-in valve
The protection against too high return temperature serves to prevent the hazardous growth in CH
boiler temperature. The user sets the maximum acceptable return temperature. In case of the
hazardous growth in temperature, the valve begins to open in order to cool the CH boiler down.
This function is activated permanently (it may be deactivated only in the service menu).
VI.a.9)
Opening direction
If the user notices, after connecting the valve to the controller, that it is connected the other way
round, then the power supply cables do not have to be switched. Instead, it is enough to change
the opening direction in this parameter:
LEFT or RIGHT.
VI.a.10)
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 PROP_COEFF 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.
Содержание ST-979
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