En
gl
is
h (
G
B)
8
12. Fault finding chart
* See service instructions on www.grundfos.com > International website > WebCAPS > Service.
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
Remedy
1. The green
"Power on"
indicator light
is off.
a) The fuses in the electric installation
have blown.
Replace the fuses. If the new fuses also blow,
check the electric installation.
b) The earth leakage circuit breaker or
the voltage-operated circuit breaker
has tripped.
Cut in the circuit breaker.
c) No power supply.
Contact the power supply authorities.
d) The PM unit is defective.
Repair or replace the PM unit.*
2. The green
"Pump on"
indicator light
is on, but the
pump does not
start.
a) The power supply to the pump is
disconnected after the PM unit.
Check the plug and cable connections, and
check if the built-in circuit breaker of the
pump is switched off.
b) The motor protection of the pump
has tripped due to overload.
Check if the motor/pump is blocked.
c) The pump is defective.
Repair or replace the pump.
d) The PM unit is defective.
Repair or replace the PM unit.*
3. The pump
does not start
when water is
consumed.
The "Pump on"
indicator light
is off.
a) Too big difference in height between
the PM unit and the tapping point.
Adjust the installation, or select a PM unit with
a higher start pressure.
b) The PM unit is defective.
Repair or replace the PM unit.*
4. Frequent
starts/stops.
a) Leakage in the pipework.
Check and repair the pipework.
b) Leaky non-return valve.
Clean or replace the non-return valve.*
c) A valve close to the PM 1 outlet has
been closed.
Open the valve.
5. The pump
does not stop.
a) The pump cannot deliver the
necessary discharge pressure.
Replace the pump.
b) A PM unit with too high start
pressure is installed.
Select a PM unit with a lower start pressure.
c) The PM unit is defective.
Repair or replace the PM unit.*
d) The non-return valve is stuck in
open position.
Clean or replace the non-return valve.*
6. The red
"Alarm"
indicator light
is permanently
on.
a) Dry running. The pump needs
water.
Check the pipework.
b) The power supply to the pump is
disconnected after the PM unit.
Check the plug and cable connections, and
check if the built-in circuit breaker of the
pump is switched off.
c) The motor protection of the pump
has tripped due to overload.
Check if the motor/pump is blocked.
d) The pump is defective.
Repair or replace the pump.
e) The PM unit is defective.
Repair or replace the PM unit.*
7. The red
"Alarm"
indicator light
is flashing.
a) Cycling. A tap has not been closed
entirely after use.
Check that all taps have been closed.