Xylem 19 001 251 R3 Floboy VFD Pumping System - Manual (Page 32)

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TROUBLESHOOTING
1. If a troubleshooting step needs to be performed by a qualified person, it is labeled “To be performed by
a qualified person only.”
2. Steps that can be performed by unqualified persons are not labeled.
3. Qualified persons are those who have been trained in avoiding the electrical hazards of working on or
near exposed energized parts. Only qualified persons may open the electrical enclosure.
4. Unqualified persons are those with little or no such training.
LOW DISCHARGE PRESSURE FAULT
Cause Cure
Flow rate greater than station capacity or
unable to pressurize the system in refill
mode (too many sprinklers on). Adjust the irrigation demand as required.
Verify the pressure set point. Has this value been changed
from the original design? If the set point has been increased,
the available flow will be lower. Check the pump curve to
verify the pump performance.
A large break in the irrigation piping. Repair the piping.
Low system pressure setting is too high. Access “Menu->Safety->Low pressure: Set Point. This is a
gage pressure setting, not relative to set point.
Low system pressure safety time is too
short. Access “Menu->Safety->Low pressure: Delay. Be careful not
to set this too high. 300 sec is normally the maximum, 60
seconds the minimum.
System pressure transducer sensing line is
valved off or clogged. Check the ball valve position, and/or blow out line.
System pressure transducer failure. Replace the pressure transducer (Flownet).
All pumps not running. One of main pump switches in OFF position.
Consult the motor troubleshooting section if the motor won’t
start (see Motor Won't Start).
Main pump discharge isolation valve is
closed. Open the valve.
Pump discharge check valve leaks. Check for foreign objects holding the valve open. Replace the
check valve if it is damaged.
DSR or PRV is partially or fully open. The pilot valve is set too low. Adjust as necessary.
The needle valve on speed control is screwed in (closed) too
far. Adjust as necessary.
There is air inside the relief valve cover. Bleed air off the valve
top.
The ball valve(s) at the inlet and/or cover tapping(s) are
closed. Open the valves.
The optional strainer at the relief valve inlet tapping is
clogged. Disassemble and clean.
There is an obstruction under the relief valve or pilot valve
seat. Disassemble and clean.
There is a leak in the relief valve diaphragm. Replace the
diaphragm.