Grundfos BMS Series - BMS Hs; 12 Fault Finding

12. Fault finding
12.1 BMS hs
DANGER
Electric shock
Death or serious personal injury
‐ Before starting any work on the product, make sure that the power supply has been switched off and that it cannot be
accidentally switched on.
Related information
7.2.2 Startup
7.3.2 Startup
12.1.1 The pump stops or starts occasionally during operation
Cause Remedy
No water supply.
The low-pressure switch has cut out.
Check that the low-pressure switch functions normally and is adjusted
correctly. Check that the minimum inlet pressure is correct. If not,
check if the feed pump is working and delivering the requested
minimum pressure.
Related information
7.2.2 Startup
12.1.2
The pump stops during operation
Cause Remedy
The fuses are blown. After a cut-out, find the cause of a possible short circuit. 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, then identify the
cause of a possible short circuit.
Check all fuses in the control circuit and replace defective fuses.
The frequency converter has tripped. Reset the frequency converter.
The motor or power cable is defective. Check the motor and cable for defects.
12.1.3 The pump runs, but generates no pressure and delivers no water
Cause Remedy
No or insufficient water supply to the pump. Check that the inlet pressure during operation is at least 1 bar for BMS
hs. If so, the water supply is OK. Stop and vent the system.
Restart the pump as described in the sections on BMS hs pumps and
startup. Check the functioning of the pump.
The pipe system or the pump is clogged. Check the pipe system and the pump. Remove all obstacles.
The prefilter is clogged. Clean the prefilter.
Related information
7.2.2 Startup
7.2.1 Before startup
12.1.4
The pump runs at reduced performance
Cause Remedy
The valves on the outlet side are partly closed or blocked. Check the valves. Put the valves in the correct position and remove all
obstacles.
The outlet pipe is partly blocked by impurities. Clean or replace the outlet pipe. Measure the outlet pressure and
compare the value with the calculated data. See the technical
specifications supplied with the system.
The pump is partly blocked by impurities. Pull the pump out of the sleeve. Dismantle, clean and check the pump.
Replace any defective parts.
The pump is defective. Pull the pump out of the sleeve. Dismantle, clean and check the pump.
Replace any defective parts.
The prefilter is clogged. Clean the prefilter.
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English (GB)