Grundfos PM 1 Service Manual

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6. Fault finding
6.1 PM 1
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 been tripped out.
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
out 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
out 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.
b) Cycling. There is a minor leakage in the system. Check the system for leakages.

Grundfos PM 1 Specifications

General

Brand	Grundfos
Model	PM 1
Category	Controller
Language	English