Fisher Scientific I903C, Operation Manual, Page: 31 / 56

4-2 Isotemp ULT Chest Fisher Scientific
Section 4
Alarms
This condition is created when the high stage compressor and fans run for
30 minutes and are not capable of cooling the 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 along with the "HS SYST FAIL" message in the LED message
center.
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 compressors will run on direct
line voltage. Under this condition, the message center will display
“VCOMPEN FAIL”.
When multiple alarm conditions occur, active messages are displayed in the
message center one at a time, updating at 5 second intervals. Pressing
Silenceduring multiple alarms causes all active alarms to be muted and to
ring back in 15 minutes.
An internal communication failure has occurred with the micro board.
During this alarm, the compressor(s) attempt to run continuously.
However, 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.
The microprocessor in Isotemp ULT freezers continually scans all probes
including the control probe, heat exchanger probe, condenser probe and
optional sample probe to ensure that they are operating properly. Should
an error be detected, the "PROBE # FAIL" alarm will occur as described
above. If an error is detected with the control probe (PROBE 1 FAIL), 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 (PROBE 2 FAIL), 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
(PROBE 3 FAIL) or optional sample probe (PROBE 4 FAIL), there is no
impact on the performance of the freezer. However, the hot condenser
alarm may also occur when the condenser probe fails. Contact the
Technical Services Department.
High Stage System Failure
Alarm
Voltage Compensation
Alarm
Multiple Alarms
Micro Board Failure
Alarm
Probe Failure Alarms
Lost Communication