Fault Finding Chart - Grundfos PM 2 Installation And Operating Instructions

12. Fault finding chart

Warning
Before starting work on the pump/PM unit, make sure that the power supply has been
switched off and that it cannot be accidentally switched on.
Fault Cause
1. The green light a) The fuses in the electric
field for "0 bar"
is off even if
b) The earth leakage circuit breaker
the power
supply has
been switched
on. c) No power supply.
d) The PM unit is defective.
2. The green a) The power supply to the pump is
"Pump on"
indicator light is
on, but the
b) The motor protection of the pump
pump does not
start.
c) The pump is defective.
d) The PM unit is defective.
3. The pump does a) Too big difference in height
not start when
water is
consumed.
b) The PM unit is defective.
"Pump on" is
off.
4. System a) DIP switch 5 set to "ON".
without
pressure tank:
b) Leakage in the pipework.
Frequent
starts/stops. c) The non-return valve is stuck in
5. System with a) The pressure tank has no
pressure tank:
Frequent
starts/stops.
b) Leaky non-return valve.
6. The pump does a) The pump cannot deliver the
not stop.
b) The start pressure is set too high.
c) The PM unit is defective.
d) The non-return valve is stuck in
7. The red a) Dry running. The pump needs
"Alarm"
indicator light is
b) The power supply to the pump is
permanently
on.
c) The motor protection of the pump
d) The pump is defective.
e) The PM unit is defective.
installation have blown.
or the voltage-operated circuit
breaker has been tripped out.
disconnected after the PM unit.
has tripped out due to overload.
between the PM unit and the
tapping point.
open position.
precharge pressure, or the tank
size is insufficient.
necessary discharge pressure.
open position.
water.
disconnected after the PM unit.
has tripped out due to overload.
Remedy
Replace the fuses. If the new fuses also blow,
check the electric installation.
Cut in the circuit breaker.
Contact the power supply authorities.
Repair or replace the PM unit.*
Check the plug and cable connections, and
check if the built-in circuit breaker of the pump
is switched off.
Check if the motor/pump is blocked.
Repair or replace the pump.
Repair or replace the PM unit.*
Adjust the installation, or increase the start
pressure.
See section 5.1 DIP switches.
Repair or replace the PM unit.*
Set DIP switch 5 to "OFF".
See section 5.1 DIP switches.
Check and repair the pipework.
Clean or replace the non-return valve.*
Check the tank precharge pressure, and
recharge the tank, if necessary.
If the size of the pressure tank is insufficient,
set DIP switch 5 to "OFF", or replace the
pressure tank.
Clean or replace the non-return valve.*
Replace the pump.
Decrease the start pressure.
Repair or replace the PM unit.*
Clean or replace the non-return valve.*
Check the pipework.
Check the plug and cable connections, and
check if the built-in circuit breaker of the pump
is switched off.
Check if the motor/pump is blocked.
Repair or replace the pump.
Repair or replace the PM unit.*
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