Sun Pumps PCC-48BLS-M2 - Manual (Page 12)

Low-Power Shut-Down/Sensorless Low Water Cut-Off Circuit (LPLW)
The Low-Power Shut-Down/ Low Water Cut-Off Circuit (LPLW) turns the pump off any time the controller output
power drops below a functional level. This may be caused by lack of power from the solar panels or from running
out of water. This protects the pump in stall conditions and saves wear on the system when no or very little water is
being pumped. This feature must be adjusted for your specific application.
This feature is always monitoring the output of the motor. If you are not interested in using this feature turn the “LP
Adj” trim pot fully counter-clockwise. This will give the pump the minimum low power set point possible.
Output Power Limit Circuit (Motor Speed Control)
The Output Power Limit Control circuit is used to control the speed of the pump motor and thus the flow rate of the
pump. It is primarily used for low producing wells where the pump output is matched to the production rate of the
well. However it can also be used any time specific flow rates are required.
Output Power Limit Adjustment
The purpose of this procedure is to adjust the output power of the controller and thus reduce the water flow of the
pump. If tests have shown the pump will out produce the well capacity, then the controller “Speed Control” feature
can be used to match the flow rate of the pump to the production of the well.
1. With the system installed and controller properly configured, allow the pump to run at full power at mid-day
until the pump starts surging.
2. Slowly turn the “Speed Control” trim pot located on the face of the controller counter clockwise until the pump
stops surging. This is the point where the pump flow rate equals the well production. This process will probably
take a few attempts to “balance” the system for optimum water production. If maximum water is not a critical
issue you may want to reduce the pumps flow rate an additional 5% to 10% to insure the pump will not run dry.
(NOTE: The trim pot has a 15- turn range. It may take multiple complete turns in a counter-clockwise direction
before you will notice any change in water output or output power on the display).