OPERATION MICRO-TEMP
®
LT, Model 749
OPERATION AND TECHNICAL MANUAL
Page 29 of 75
3-5. STATUS DISPLAY AND INDICATOR MESSAGES
The status display reports the water temperature and set point temperature of the unit or indicates
changes the operator must make. The status display can show different messages to guide the
operator. The following list defines each message and describes the changes, if any, that the
operator must make.
A. During normal operation, the status display shows the following message:
The water temperature value is displayed when the Micro-Temp
®
LT
system is operating. If the “SET” button is being depressed, the set
point temperature is being displayed. In any other case, the actual
water temperature inside the reservoir is being displayed.
Note: If the display temperature is flashing, the water temperature is
>1°C (2°F) from the set point temperature.
B. The following are indication messages and/or indicators:
Indication Message or
Indicator
This message flashes when the water temperature sensor is open or
defective. While this message displays, an audible indicator sounds
continuously, the red “Power Failure/Caution” LED illuminates, and
the pump and heater shut off. The indicator stops and the unit
resets when the unit has been powered down. The unit should not
be used again until it is serviced.
This message flashes when a membrane keypad fault occurs (i.e.
the “Set” button is closed at power up). While this message displays,
an audible indicator sounds continuously, the red “Power
Failure/Caution” LED illuminates, and the pump and heater shut off.
The indicator stops and the unit resets when the unit has been
powered down. The unit should not be used again until it is
serviced.
This message flashes when a failure within the microprocessor
occurs. While this message displays, an audible indicator sounds
continuously, the red “Power Failure/Caution” LED illuminates, and
the pump and heater shut off. The indicator stops and the unit resets
when the unit has been powered down. The unit should not be
used again until it is serviced.
HL
(High Limit Indicator)
This indicator condition occurs when the circulating water
temperature has reached the high temperature limit of 44˚C ± 0.5˚C
(111˚F ±1˚F). When this occurs, the red “Power Failure/Caution”
LED illuminates, an audible indicator sounds continuously, and the
pump and heater shut off. This indicator condition cancels only after
the unit has been powered down and the water temperature has
cooled below 42˚C. The unit should not be used again until it is
serviced.
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