Grundfos MGE F, Service Instructions Manual

Page: 12 / 32

English (GB)
12
On On
3. The pump is running at
minimum speed.
– The setpoint signal is
outside the set signal
range.
a) Set the pump to "open loop" operation, and connect 10 V supply to the
setpoint input.
Does the pump switch to maximum speed?
NO:
YES: Proceed to point b).
The pump is OK.
b) Does the setpoint setting correspond to the setpoint type installed? (0-
10 V, 0-20 mA, 4-20 mA)
NO:
YES:
Correct the setting using Grundfos GO Remote or PC-Tool
E-products.
Proceed to point c).
c) Is the voltage to the setpoint connection 10 VDC?
TM
02
16
0
7
47
20
NO:
YES: Replace the terminal box.
Proceed to point d).
d) Is the setpoint signal
– below 10 V (type 0-10 V sensor)?
– below 20 mA (type 0-20 mA sensor)?
– between 4 and 20 mA (type 4-20 mA sensor)?
NO:
YES:
Check for fault in the external setpoint signal.
Re-establish the correct setpoint signal, if necessary.
If the pump still does not run correctly, replace the terminal
box.
On Off
Normal operation
1. The pump is running.
– Normal operational state.
2. The pump is not running.
Operational stop which may
be caused by
– the flow switch connected
– the pump stop function.
a) The flow switch is closed.
Is there 5 VDC across terminals 1-9?
(If an extended I/O module is installed, the flow switch may be
connected to DI3 (terminals 9-10) or DI4 (terminals 9-11)).
NO:
YES:
Flow switch closed = Pump is not supposed to run.
Flow switch open = Pump must be running.
If the flow switch is defective, replace it.
The connection of a flow switch depends on the MGE functional
modules. See the wiring diagrams in figs
8 to 11 .
Does the pump start when the connection between the flow switch
terminals is cut?
NO:
YES:
Replace the I/O module.
The digital input is OK.
The flow switch is defective. Replace it.
b) The stop function has stopped the pump.
Does the pump start when you increase the flow and/or reduce the
pressure in the system?
NO:
YES:
If the sensor is OK, replace the terminal box.
The input is OK.
Indicator lights
Condition/cause Remedy
Green Red
0-10V
+
-
0/4-20mA
10K
4: SETPOINT
5: +10V
6: GND