Fault Finding - Grundfos ALPHA1 Series Installation And Operating Instructions Manual

12. Fault finding

Warning
Before starting work on the pump, switch off the
power supply. Make sure that the power supply
cannot be accidentally switched on.
Fault Control panel
1. The pump does
not run.
Light off.
Display shows "- -".
"POWER ON" is on only.
2. Noise in the
system.
Shows normal operating
status.
3. Noise in the
pump.
Shows normal operating
status.
4. Insufficient heat.
Shows normal operating
status.
22
Cause
a) A fuse in the installation is blown.
b) The current-operated or voltage-
operated circuit breaker has tripped
out.
c) The pump is defective.
a) Power supply failure. The power
supply might be too low.
b) The pump is blocked.
a) Air in the system.
b) The flow is too high.
a) Air in the pump.
b) The inlet pressure is too low.
a) The pump performance is too low.
Remedy
Replace the fuse.
Cut in the circuit breaker.
Replace the pump.
Check that the power supply falls within
the specified range.
Remove the impurities.
Vent the system. See section
10.3 Venting of heating systems.
Reduce the suction head. See section
11. Pump settings and pump
performance.
Let the pump run. It vents itself over time.
See section 10.2 Venting the pump.
Increase the inlet pressure or check the
air volume in the expansion tank, if
installed.
Increase the suction head. See section
11. Pump settings and pump
performance.