SQFlex Service Instructions
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8. CU 200 indicates 
‘F4 = overload’.
Too low input voltage. 
• Increase the supply voltage, to 30 VDC or 
higher.
Pump is defective.
• Repair or replace the pump.
Only helical rotor 
pumps. Pumped liquid is 
contaminated with oil or 
similar substance.
• Clean the liquid and replace the pump.
Motor liquid low / Missing.
• Check or refill motor liquid.
9. Green indicator light 
in ON/OFF button is 
flashing.
Insufficient power supply.
• Increase the number of solar modules or con-
nect an alternative energy supply, such as wind 
turbine, batteries or generator.
Pump has seized up.
• Clean the pump.
10.Running light on CU 
200 but low wattage.
System not grounded.
• Check system for adequate grounding
Pump is defective.
• Repair or replace the pump.
If a centrifugal pump is used: Check that the riser 
pipe is not blocked.
11. No light in front 
cover. Pump delivers 
water.
CU 200 is defective.
• Replace the CU 200.
Ribbon cable not 
mounted.
• Mount the ribbon cable.
12.Pump does not stop 
when water reservoir 
is full.
Fault indicator light 
on CU 200 is off.
Level switch is dirty or 
defective.
• Clean or replace the level switch.
Cable on level switch is 
damaged.
• Replace the cable.
13.Pump does not stop 
when water reservoir 
is full. 
Fault indicator light 
on CU 200 is on.
CU 200 is defective.
• Replace the CU 200.
14.Pump does not start 
when water reservoir 
is empty.
Water reservoir indi-
cator is on.
Level switch is defective.
• Replace the level switch.
Cable on level switch is 
damaged.
• Replace the cable.
CU 200 is defective.
• Replace the CU 200.
Indication/Fault Possible cause Remedy
sqflex_SI_US_WG.book Page 11 Thursday, October 1, 2009 3:27 PM










