Data Flow Systems TCU800, Installation And Operation Manual, Page: 81 / 162

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V i e w i n g a n d T r o u b l e s h o o t i n g A l a r m s
When a float sequence fault alarm occurs:
• Check the floats or pressure switches for the fault. Verify that the corresponding Well Level LED illuminates when
each float or pressure switch is on.
• Measure the voltage between the corresponding level input terminal and the IN_COM_2 terminal. The voltage should
be 10-30 VAC or VDC with the switch closed and 0 (zero) V with the switch opened.
• Check the wiring and verify all of the following:
- Only one bias source is used to bias all floats or pressure switches.
- The same voltage-dropping resistor is used for all floats or pressure switches.
- The return for the bias voltage is properly connected to the IN_COM_2 terminal.
- If ALM_SIL and AUX_IN are used, verify that they use the same bias voltage and dropping resistor value as the
level inputs.
High Well Alarm
The HiWell fault indicates that the HI_LVL input terminal is ON. Alternatively, if an analog transducer is being used,
HiWell indicates that the level has risen above the High-level set point
If an erroneous alarm occurs, check the high float or pressure switch and wiring.
• When the switch is opened, 0 (zero) VAC/VDC, should be measured at the HIGH_LVL input.
• Measure the voltage between the HIGH_LVL and IN_COM_2 terminals.
• Make sure the high float or pressure switch is not fouled or shorted.
• If necessary, disconnect the HIGH_LVL input to isolate the problem further.
Phase Sequence Fault
The TCU’s phase monitor is designed to detect phase losses, high and low phase faults, and phase sequence faults.
When the TCU detects a phase fault, it disables the pump motor outputs and activates the alarm light and horn relays. If a
phase is missing or the power is interrupted, the TCU also indicates that a phase sequence fault has occurred by issuing a
PhaSeq alarm.
If a sequence fault occurs, check the phase rotation of the incoming power. The label on the TCU’s connector indicates the
connection for clockwise phase rotation.
If the incoming power is labeled for counter-clockwise phase rotation, two of the leads wired into the TCU must be
swapped. Turn off the main breaker before making any wiring changes. After the changes are made, turn on the main
breaker and reconfigure the TCU’s High and Low phase-voltage thresholds See “Low- and High-Limit Phase Voltage” on
page 123 in “Chapter 10: Configuring the Pump Control Process” for instructions on changing these thresholds.
If the problem cannot be resolved, the TCU may require factory service. See “Appendix H: Support, Service, and Warranty”
for removal, replacement, and servicing instructions.