Grundfos Control MPC-Serie Installationsanleitung Seite 63

8.7.60 Pumps outside duty range (4.4.7)
Fig. 111 Pumps outside duty range
Description
The function gives a warning if the duty point of the pumps moves
outside the defined range. For instance, if the inlet pressure
becomes lower than a minimum permissible value, thus causing a
risk of cavitation for some pump types.
The warning is given with a set time delay. You can set whether
the warning is to be reset automatically or manually when the
duty point comes within the defined duty range. You can also set
a relay output to be activated when the warning is given, and to
be deactivated when the warning is reset.
This function requires that the outlet pressure and the inlet
pressure (either measured or configured) or the differential
pressure of the pumps is monitored, and that CU 352 contains
valid pump data from either a GSC file or from manual input. See
section 8.7.43 Pump curve data
Setting range
• Setting of manual or automatic resetting.
• Setting of warning delay.
Setting via the operating panel
• Settings > Monitoring functions > Pumps outside duty range >
Manual or Auto > Set warning delay.
Factory setting
The function is disabled.
(4.3.19).
8.7.61 Pressure relief (4.4.8)
Fig. 112Pressure relief
Description
The purpose of the function is to reduce the pressure in the pipes
by opening a solenoid valve if it exceeds a set limit. If the
pressure is not reduced within a given time, the solenoid valve
will be closed, and a warning can be given.
1: Solenoid valve opens.
2: Solenoid valve closes.
3: Solenoid valve opens.
4: Warning is activated.
5: Solenoid valve closes, and warning
P [bar]
is reset.
1
Valve opening
pressure
Valve opening pressure
minus band
Fig. 113Pressure relief
Setting range
• Setting of digital output.
• Setting of pressure to be monitored.
• Setting of valve opening pressure.
• Setting of band for valve opening pressure.
• Setting of warning or alarm.
2 3 4
5
Band
Time [s]
Warning delay
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