Grundfos Medium UPM Series Data Booklet page 33

Medium UPM
Fault finding
Fault
1. Pump is not running. No
power supply.
2. Pump is not running. Normal
power supply.
3. Pump runs at maximum
speed and cannot be
controlled.
4. Noise in the system.
5. Noise in the pump.
6. Insufficient flow.
Cause
• System is switched off.
• A fuse in the installation is blown.
• The circuit breaker has tripped.
• Power supply failure.
• Controller is switched off.
• Pump is blocked by impurities.
• Pump is defective.
• No signal from signal cable.
• There is air in the system.
• Differential pressure is too high.
• There is air in the pump.
• Inlet pressure is too low.
• Pump performance is too low.
• Hydraulic system is closed or system pressure is
insufficient.
Remedy
Check the system controller.
Replace the fuse.
Check the power connection and switch on the circuit
breaker.
Check the power supply.
Check the controller and its settings.
Remove impurities. Unscrew the deblocking screw at the
front of the pump. Deblock the pump from the front of the
control box with a screwdriver. Be aware of splashing hot
water.
Replace the pump.
Check if the cable is connected to the controller. If it is,
replace the cable.
Vent the system.
Reduce the pump performance at the pump or external
controller.
Let the pump run. The pump vents itself over time.
Increase the system pressure or check the air volume in
the expansion tank, if installed.
Check the external controller and the pump settings.
Check the non-return valve and filter. Increase the
system pressure.
10
33