13
18.2 BM hp circulation pump
Warning
Before starting work on the BM hp circulation pump, make sure that the electricity supply has been switched off and
that it cannot be accidentally switched on.
Fault
Cause
Remedy
1.
The pump stops
occasionally.
a) No or insufficient water supply.
The pressure switch has cut out.
Check that the pressure switch functions normally
(without delay) and is adjusted correctly. Check that the
minimum inlet pressure is correct.
b) The capacity is too small.
The flow switch has cut out.
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.
2.
The pump does not run. a) The fuses are blown.
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.
b) The motor starter overload unit has tripped
out.
Reset the starter overload. If it trips out again, the
voltage should be checked.
c) The magnetic coil of the motor starter/
contactor is short-circuited (not cutting in).
Replace the coil. Check the coil voltage.
d) The control circuit has cut out or is defective. Check the control circuit and the contacts in the
monitoring devices (pressure switch, flow switch, etc.).
e) The motor/supply cable is defective.
Check motor and cable. See section
.
3.
The pump runs, but
gives no water nor
develops any pressure.
a) No or insufficient water delivered to the
pump or air in the system.
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
If the pump is defective, it should be dismantled and
repaired/replaced.
b) Suction parts are blocked.
Pull the pump out of the sleeve and clean the suction
parts.
4.
The pump runs at
reduced capacity (flow
and pressure).
a) Wrong direction of rotation.
See section
.
b) The valves on the discharge side are partly
closed or blocked.
Check the valves.
c) The discharge pipe is partly blocked by
impurities.
Measure the discharge pressure and compare with the
calculated data. Clean or replace the discharge pipe.
d) The pump is partly blocked by impurities.
Pull the pump out of the sleeve. Dismantle, clean and
check the pump. Replace defective parts.
e) The pump is defective.
Pull the pump out of the sleeve. Dismantle, clean and
check the pump. Replace defective parts.
