Sterlco M2B+ Controller - Manual (Page 35)

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Low Fluid Level Alarm
This factory-set alarm occurs when the low level switch is in a closed condition. This is not a
critical alarm and will reset once the condition is cleared. For water TCUs the Low Level
alarm disables the heater and the pump motor outputs. For oil TCUs it disables the heater
output. There are no menus that affect this alarm.
High Fluid Level Alarm
This factory-set alarm occurs when the high level switch is in a closed condition. This alarm
is only applicable for water TCUs. This is not a critical alarm and will reset once the
condition is cleared. It is an alarm only and no outputs are disabled.
Pump Failure Alarm
This critical, factory-set alarm occurs when one of three conditions occurs: phase loss, phase
reversal, or motor overload trip. If any of these occur, the heat, cool, and pump motor
outputs are disabled. Turn the unit off and then on again to reset the fault.
Safety Thermostat Alarm
This critical, factory-set alarm occurs when the thermostat sensor opens on a high
temperature condition. For both water and oil TCUs, the heater output is disabled, but the
pump and cooling outputs are still active. For water TCUs, the cooling output will latch on.
Turn the unit off and then on again to reset the fault.
Welded Contactor Alarm
This critical factory-set alarm occurs when the controller senses that an auxiliary contact has
remained closed after a preset time period after the heater output has been turned off. The
heater output is disabled, and the cool and pump motor outputs are enabled to prevent
temperature runaway. This alarm is an option for water TCUs and is standard for oil units.
Turn the unit off and then on again to reset the fault.