Fault Finding - Grundfos ALPHA Series Installation And Operating Instructions Manual

7. Fault finding

Warning
Before starting any work on this circulator, make sure electrical supply has been
switched off and that it cannot be accidentally switched on.
Pump liquid may be scalding hot and under high pressure.
Fault
1. The pump does not run
2. Noise in the system
3. Noise in the pump
4. Insufficient heat
8
Control panel
LED off
LED on
___ ___
" "
LED on
LED on
LED on
Remedy
Check power supply (voltage) and
circuit breaker.
Check zone control, voltage, control
options, and thermostat.
Check all power connections.
Damaged circulator / replace.
Check that the electricity supply falls
within the specified range.
Impeller blocked by impurities.
Requires turning power OFF and back
On to pump. Check for air, locked rotor
and/or voltage.
Install air eliminator.
Reduce the pump speed.
Fluid velocities too high; reduce pump
speed.
Emitter or piping expanding.
Let the circulator run, will vent over time.
Increase the inlet pressure or check the
air volume in the expansion tank, if
installed.
No fluid (dry running).
Damaged circulator / replace.
Increase circulator speed or constant
pressure.
Circulator in proper operating mode.
Check for air, piping, zone(s) and
emitter(s).
Check thermostat(s).
Check all valving.
Heat emitter large enough.
Check direction of flow.
Check water temperature from boiler
and boiler functions.
Check proper sizing of circulator.
Check T calculation.