Fault Finding Chart - Grundfos PM 2 Montage- Und Betriebsanleitung

12. Fault finding chart

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