Fault Finding 7 Caution - Grundfos CMB Manual Del Usuario

7. Fault finding
Warning
Before starting work on the pump, make sure that the power supply has been switched off
and that it cannot be accidentally switched on.
Fault
1. The green "Power
on" indicator light is
off.
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.
The "Pump on"
indicator light is off.
4. Frequent
starts/stops.
5. The pump does not
stop.
6. The red "Alarm"
indicator light is
permanently on.
7. The red "Alarm"
indicator light is
flashing.
Cause
a) The fuses in the electric installation
have burnt.
b) The earth leakage circuit breaker or
the voltage-operated circuit breaker
has tripped.
c) No power supply.
d) The PM unit is defective.
a) The power supply to the pump is
disconnected after the PM unit.
b) The motor protection of the pump
has tripped due to overload.
c) The pump is defective.
d) The PM unit is defective.
a) Too big difference in height between
the PM unit and the tapping point.
b) The PM unit is defective.
a) Leakage in the pipework.
b) Leaky non-return valve.
c) A valve close to the PM 1 outlet has
been closed.
a) The pump cannot deliver the
necessary discharge pressure.
b) A PM unit with too high start
pressure is installed.
c) The PM unit is defective.
d) The non-return valve is stuck in
open position.
a) Dry running. The pump needs water. Check the pipework.
b) The power supply to the pump is
disconnected after the PM unit.
c) The motor protection of the pump
has tripped due to overload.
d) The pump is defective.
e) The PM unit is defective.
a) Cycling. A tap has not been closed
entirely after use.
Remedy
Replace the fuses. If the new fuses
also burn, check the electric
installation.
Cut in the circuit breaker.
Contact the power supply company.
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 select a PM
unit with a higher start pressure.
Repair or replace the PM unit.
Check and repair the pipework.
Clean or replace the non-return valve.
Open the valve.
Replace the pump.
Select a PM unit with a lower start
pressure.
Repair or replace the PM unit.
Clean or replace the non-return valve.
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.
Check that all taps have been closed.
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