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SECTION 5
TROUBLESHOOTING
ECC moves to same position regard-
less of signal applied
• Improper command signal applied to ECC. Connect mA
meter into signal line. Read signal. If necessary, correct
signal source, possible broken wire, loose connection,
etc.
• Mode setup incorrect. Review initial start-up procedure.
• Feedback potentiometer gear slipping or worn. Manually
move knob, apply control signal, and observe gear. If
necessary, replace feedback potentiometer assembly.
Limit lights flicker as ECC moves
• Bad feedback potentiometer. With oscilloscope, observe
pot signal while in motion. If necessary, replace feed-
back potentiometer assembly.
• Bad connection at plugs. Check continuity. Repair or
replace plugs and/or wiring as necessary.
• Bad printed circuit board. Replace PC board.
ECC does not respond to 4-20 mA
command signal
• No power to ECC. Correct by applying AC power to
ECC.
• Polarity of 4-20 mA signal wires connected to terminals
may be backwards. Check polarity and correct if
improper.
• Motor frozen in place. With power off, use handwheel to
check motor rotation. Replace motor if necessary.
• Potentiometer bad. Replace potentiometer.
• Bad printed circuit board. Replace PC board.
ECC will only travel in one direction
• Bad printed circuit board. Replace PC board.
ECC chatters or vibrates
• ECC is driving the pump adjustment against the pump’s
mechanical stop. Reset the ECC and pump high and
low limits per calibration procedure.
• If limits are okay, then circuit board and/or feedback
potentiometer should be replaced.
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