Lingenfelter TechAFX VariMax PumpOperationDetails - Manual (Page 8)

VariMax: PWM 'out' diagram
Pump Fault 88-90%
A) Impeller Blockage (sustained Low back EMF) - If 5 consecutive blockage events (see Pump Warning “A”
low back EMF) have occurred, this mode is entered. The pump will stop. The pump will not restart until a
power re-cycle occurs.
B) Over Temperature - The high temperature operation limit is exceeded. The pump stops and stays in this
state until the unit cools.
C) Over-Current at startup - if an over-current occurs during initial activation of FETS, the pump is stopped
until a power re-cycle occurs.
D) Over-Current during operation (sustained over-current during operation) - After 5 consecutive cycles of
“Over-Current during normal operation” (See Pump Warning “C”), the pump is stopped until a power re-cycle
occurs.
Pump Warning 4 - 6%
A) Low Back EMF (possible impeller blockage) – Stops forward rotation, reverses the motor for 2.5s to
clear potential impeller blockage, and then restarts.
B) High temperature warning (Temperature is close to operational thermal limit)
Motor slows to 2500RPM, in an attempt to cool. The lower RPM lowers the current which in turn, lowers the
pump self heating characteristic. The pump exits this mode once the temperature (warning condition) has
moved below the full operation temperature limit (timing is unspecified).
C) Over-Current during normal operation (possible problem) - If an over-current occurs during normal
operation the pump is stopped. After a 10 second wait, the pump will attempt to restart.