Bm Hp Circulation Pump - Grundfos BMEX Series Montage- Und Betriebsanleitung

22.2 BM hp circulation pump

Warning
Before starting work on the BM hp circulation pump,
make sure that the power supply has been switched
off and that it cannot be accidentally switched on.
Fault Possible cause
1. The pump stops a) No or insufficient water supply.
occasionally.
b) The capacity is too small. The flow switch
2. The pump does not run. a) The fuses are blown.
b) The motor starter overload unit has tripped.
c) The magnetic coil of the motor starter/
d) The control circuit has cut out or is defective. Check the control circuit and the contacts in the
e) The motor/supply cable is defective.
3. The pump runs, but a) No or insufficient water supply at the pump
gives no water nor
develops any pressure.
b) Suction parts are blocked.
4. The pump runs at a) Wrong direction of rotation.
reduced capacity (flow
b) The valves on the discharge side are partly
and pressure).
c) The discharge pipe is partly blocked by
d) The pump is partly blocked by impurities.
e) The pump is defective.
22
The pressure switch has cut out.
has cut out.
contactor is short-circuited (not cutting in).
or air in the system.
closed or blocked.
impurities.
Remedy
Check that the pressure switch functions normally
(without delay) and is adjusted correctly. Check that the
minimum inlet pressure is correct.
The discharge pipe is totally or partly blocked due to
incorrectly adjusted manually operated valve, or failure
in the solenoid or motor-operated valve. Check these
valves.
The flow switch is faulty or incorrectly adjusted. Check/
adjust the switch.
After a cut-out, the cause of a possible short-circuit must
be found.
If the fuses are blown, check whether the motor starter
has been set correctly or is faulty.
If the fuses are hot when they are replaced, check that
the load of the individual phases does not exceed the
motor current during operation. Identify the cause of the
load.
If the fuses are not hot immediately after the cut-out, the
cause of a possible short-circuit must be identified.
Possible fuses in the control circuit must be checked,
and defective fuses must be replaced.
Reset the starter overload. If it trips again, check the
voltage.
Replace the coil. Check the coil voltage.
monitoring devices (pressure switch, flow switch, etc.).
Check motor and cable. See also section
connection.
Check that the inlet pressure during operation is at least
0.5 bar. If so, the water supply is OK. Stop and vent the
system. Restart the system as described in section
9. Startup and operation.
If the pump is defective, it should be dismantled and
repaired/replaced.
Pull the pump out of the sleeve, and clean the suction
parts.
See section 9.7.1 Checking the direction of
Check the valves.
Measure the discharge pressure and compare the value
with the calculated data. Clean or replace the discharge
pipe.
Pull the pump out of the sleeve. Dismantle, clean and
check the pump. Replace defective parts.
Pull the pump out of the sleeve. Dismantle, clean and
check the pump. Replace defective parts.
7. Electrical
rotation.