Grundfos DDI 222 Montage- Und Betriebsanleitung Seite 40

9.10.4 Pressure control function
To protect the pump and system against excessive
Caution
pressure build-up, install an overflow valve in the
discharge line.
The pressure sensor monitors the pressure in the dosing head. If
the set pressure is exceeded by 0.5 bar, the pump switches off.
When switched on, the electronics detects whether the chamber
pressure control function is activated.
• "bar" appears in the display.
Manual
1.210
Fig. 45 Display: "Pressure control"
Pressure exceeded
If, after one stroke, the cut-off pressure is exceeded, this is
recognised as an error:
• The pump is stopped.
• The error signal relay switches on.
• The LED alternately flashes red and green.
• The last pressure value to be measured is displayed.
• "RUN", "ERROR" and "bar" flash in the display.
Manual
8.99
RUN*
ERROR*
Fig. 46 Display: "Pressure exceeded"
Pump restart attempts:
• First the pump makes four attempts to restart, each separated
by a 2-second pause, if the chamber pressure has fallen below
the cut-off pressure (p < p
act
• After the pressure was exceeded, the pump restarts smoothly.
If the set cut-off pressure is exceeded, the pump is stopped
again immediately.
• After four attempts, the pump waits 10 minutes before
attempting to automatically restart again.
• The pump continuously attempts to restart if the chamber
pressure decreases in this way.
Pump running
Pump waiting
Fig. 47 Pump restart attempts
Error correction
• Press the "Start/Stop" button to stop the pump and prevent it
from restarting.
• Check the discharge valve and the installation on the
discharge side and correct any errors, if necessary.
For maintenance work, see section
• Check and correct the pressure setting, if necessary.
Once the error has been corrected,
• press the "Start/Stop" button to restart the pump.
– The pump returns to the state it was in before the error
occurred.
40
l/h
bar
bar*
).
set
Pressure exceeded
2 sec.
10. Maintenance .
10 min.
10 min.
Displaying the pressure that has been measured
The pressure that has been measured during the pump operation
can be displayed at any time.
• Press the "Menu/Info" button twice. (If only pressed once, the
dosed quantity is displayed.)
– The pressure is displayed for approximately 10 seconds.
....