Data Flow Systems TCU800, Installation And Operation Manual

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disabled from the TCU’s local configuration. All conditions that activate the alarm horn and alarm light are reported
through the telemetry system.
Alarm outputs are activated only when the TCU detects an alarm condition, such as phase faults, high and low-well
conditions, and internal TCU faults. The alarm horn can be silenced by pressing the TCU’s Silence switch, by viewing the
TCU’s alarm screen from a telemetry-provided alarm silence control point or from a momentary switch connected to the
TCU’s Alarm Silence input. Any new alarm condition reactivates the alarm horn.
Failure Modes
Pump Failure
The TCU can operate around a pump that has failed and can be configured to retry the failed pump after a delay. If the retry
function is disabled, the TCU will alternate around the faulted pump until it is taken out of service via its corresponding
H-O-A switch.
Phase 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. The TCU’s
H-O-A switches can be used to override the TCU’s phase monitor and control the pumps during a phase fault.
Analog Transducer Fault
The conditions that cause a transducer fault alarm to be generated are based on the TCU’s configuration. A few of the
conditions that can cause a transducer fault are:
• Transducer low condition
• High float condition
The TCU provides several options for maintaining well and tank levels when a transducer fault occurs. Control pumps
using:
• High and/or low float
• Second analog transducer
• Float system (Off float and at a minimum a Lead or High float)
• Combination of a high and/or low float and the desired fault mode (timer, second transducer, floats)