GESTRA LRR 1-52, Original Installation & Operating Manual

Page: 9 / 72

9 LRR 1-52, LRR 1-53, URB 55 - USA - Installation & Operating Manual -
850703-00
Specialist terms, abbreviations
Flushing the continuous blowdown valve
The continuous blowdown valve can be flushed automatically to prevent it from sticking. In this case,
the continuous blowdown valve is actuated at intervals (flushing interval) and opened for a certain
time (flushing time). After the flushing time, the valve moves to the position set by the control.
Operating position of the continuous blowdown valve
The operating position of the continuous blowdown valve ensures that the electrode comes into
contact with a representative sample of boiler water.
Standby mode (conductivity control)
To prevent loss of water, continuous blowdown control and automatic intermittent blowdown (if
enabled) can be disabled in standby mode or when the burner is switched off. An external control
command causes the continuous blowdown valve to move to the CLOSED position. The MIN/MAX
limits and monitoring functions remain active in standby mode.
When the equipment is back in normal mode, the continuous blowdown valve returns to the control
position. An intermittent blowdown pulse is also triggered (if automatic intermittent blowdown is
enabled and a blowdown interval and blowdown time have been set).
Pb (proportional band)
The proportional band enables the controller amplification to be adapted to suit the controlled
system. For further information, see page 9, guide to setting control parameters.
Ti (reset time)
The integral element ensures that control deviations can be fully corrected, with no remaining
deviation. For further information, see page 9, guide to setting control parameters.
Dead band
If the actual value reaches the (set point +/- of the dead band), the manipulated variable does
not change in this band, see page 9.
PI controller
Controller with proportional (P) and integral (I) control.
LRR .. / LRG .. / LRGT .. / URB ..
GESTRA equipment and type designations, see page 9.
SELV
Safety Extra Low Voltage