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Section 3
Section 3
Alarms
Alarms
High Stage System
Probe Failure Alarm
Compensation Alarm
Micro Board Failure
Alarm (E07)
Lost Communication
Alarm ( ---- )
3-2
Model 900 Series
The "high stage system failure" condition is created when the high stage
compressor and fans run for 30 minutes and are not capable of cooling the
Failure
interstage heat exchanger to the proper temperature. Under this condition,
the high stage compressor and fans will turn off after 30 minutes and an
audible and visual alarm will occur. The audible alarm can be silenced and
will ring back every 15 minutes.
The microprocessor in Model 900 Series freezers continually scans all
probes including the control probe, heat exchanger probe and condenser
probe to ensure that they are operating properly. Should an error be
detected, the "Probe Failure" alarm will occur as described above. If an
error is detected with the control probe, the high and low stage
compressors will run continuously. As a result, the cabinet temperature
will decrease until it reaches the lowest temperature that the refrigeration
system can maintain. If an error is detected with the heat exchanger probe,
the freezer will cycle properly at its temperature set point using a 5 minute
step start between the high and low stage compressors. If an error is
detected with the condenser probe, there is no impact on the performance
of the freezer; however, the hot condenser alarm may also occur. Contact
the Technical Services department (1-888-213-1790) or your local
distributor.
Voltage
If the freezer is compensating for high or low line voltage, the system will
measure the compensated AC voltage. If the voltage is incorrect, the unit
will stop attempting to compensate, and the compressor will run on direct
line voltage. Under this condition, there will be a visual and audible alarm
that can be silenced with a ringback period of fifteen minutes. This alarm
condition is unlikely to occur, and as such, there is no LED alarm
indicator for this condition.
An internal communications failure has occurred with the micro board.
Under this condition, a visual and audible alarm occurs that can be
silenced with a ringback period of 15 minutes. The temperature displays
reads "E07", and the remote alarm contacts trip. During this alarm, the
compressor(s) attempt to run continuously. With this type of failure,
freezer operation becomes undependable.
Communication between the micro board and the display board has been
lost. Under this condition, the visual alarm flashes along with dashes in the
temperature display (----). Contact Technical Services.
Thermo Scientific
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