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and verify that the supply valve is open.
If equipped with a suction manifold strainer, clean as
required.
Ensure the supply piping not clogged or restricted.
Pressure is actually low – dynamic.
Ensure that the flow rate is less than the supply
capacity.
LOSS OF PRIME FAULT
Cause
Cure
Normally used on end-suction centrifugal pumps
System has lost prime or air is trapped in system.
Check the system for prime lead in the foot valve or
suction line.
Probe is dirty, corroded, or failed.
Clean or replace the probe as required.
Loss of prime relay failed.
To be performed by a qualified person only.
Check the relay for proper operation. Replace as
required.
PHASE FAULT
Cause
Cure
Previous power failure.
Press the station reset. If the problem is gone, the
fault will reset.
Incoming line voltage less than 90% of rated station
voltage.
Consult the power company.
Phase monitor voltage set too high.
To be performed by a qualified person only.
Example – monitor set at 480 V, try 460 V.
To be performed by a qualified person only.
Check all input fuses.
One or more dead legs on a 3-phase power line.
Call the power company.
A reversal, shift, or imbalance of the line phases.
Normally occurs after the power company has worked
on or replaced the transformer. Call the power
company.
Phase monitor failure.
To be performed by a qualified person only.
If the LEDs on the phase monitor are on, there is no
fault. If the LEDs are off, and all voltage and phase
conditions are good, the phase monitor needs to be
replaced.
VFD FAULT
Cause
Cure
Look at VFD keypad to determine specific fault and consult the VFD manual.
Codes identified below are some of the more common ABB 550 codes. Consult your specific VFD
manual for other drive applications.
Fault code 3 – dev overtemp (drive heatsink is
overheated).
To be performed by a qualified person only.
The VFD fan won’
t come on. If there is no power, check
circuit breaker. Check for no continuity across transorb
