GESTRA SPECTORcontrol II, Original Installation & Operating Manual

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Important notes
Definition of terms
Standby mode (conductivity control)
To prevent water losses, continuous blowdown control and automated intermittent blowdown (if ena-
bled) can be disabled in standby mode or when the burner is switched off. The continuous blowdown
valve moves to CLOSED position, triggered by an external control command. The MIN/MAX limits and
monitoring function remain active in standby mode.
After the equipment has switched back to normal operation, the continuous blowdown valve is
moved into the OPERATING or control position. In addition, an intermittent blowdown pulse is
triggered, based on your settings.
Temperature compensation (conductivity control)
The electrical conductivity of water changes as the temperature falls or rises. To obtain meaningful
readings, it is therefore necessary to base the measurements on the reference temperature of 25°C,
and to correct the measured conductivity using a temperature coefficient.
Switching is no longer possible in the SPECTOR connect , TK Linear is the only option.
TK (Linear)
To ensure the reading is based on 25 °C, set the TK between 0 and 3.0 % per °C (the default is
2.1 % per °C). This ensures linear temperature compensation of the reading over the entire measur-
ing range. This method is usually applied for steam generating units operating at a constant service
pressure. When the TK is set and the service pressure has been reached, use a calibrated conductiv-
ity meter to measure the conductivity of the boiler water, and compare the reading with the indicated
conductivity value. If the reading differs from the indicated conductivity, change the TK setting until
they tally.
TK (standard)
Since the relationship between conductivity and temperature is not linear over a larger temperature
range, various conditioning agents and different basic conductivities were used to establish empirical
conductivity/temperature curves. These curves are stored as standard curves and can be used for
temperature compensation. TK (STANDARD) is suitable for steam generating units operating with var-
iable pressure, i.e. that do not have a fixed working pressure (e.g. low load 10 bar, full load 15 bar).
TK (AUTO)
With this method, a plotted, installation-specific conductivity/ temperature curve is used for tempera-
ture compensation. This curve is plotted during the heating process and stored as an Auto curve. The
TK (AUTO) method is particularly suitable for steam generating units operating with variable pressure.
Cell constant and correction factor (conductivity control)
The geometric variable (cell constant) of the conductivity electrode is taken into account when calcu-
lating the conductivity. However, this constant may change during operation, e.g. due to soiling of the
measuring electrode. Deviations can be corrected by changing the correction factor. If the correction
factor is too high, a warning is displayed and the electrode must be cleaned.
Flushing the continuous blowdown valve
The continuous blowdown valve can be flushed automatically to prevent it from sticking. For this, the
continuous blowdown valve is actuated at intervals and opened for a certain time. After the flushing
time, the valve is moved into the OPERATING position or into the required control position.
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