5.3 Troubleshooting Chart - Freezing Chamber (continued)
Problem Probable
Cause
Remedy
Fan is not operating.
Faulty limit switch.
Replace switch.
Fan has not been energized at the controller.
Energize fan at controller.
Fan is jammed or motor is defective.
Mechanically free fan and/or replace fan motor.
Inability to sufficiently
LN2 transfer hose connected to vent side of supply tank.
Connect transfer hose to liquid side of
cool specimens.
supply tank.
Controller is improperly set.
Readjust controller setting (add Cool+).
Insufficient liquid nitrogen pressure at freezing chamber.
Increase liquid nitrogen supply pressure
to 22 PSIG as measured at the freezing chamber.
Defective limit switch.
Replace limit switch.
Nitrogen gas is escaping
Liquid nitrogen pressure supply is too high.
Reduce liquid nitrogen pressure to 22 PSIG.
from pressure relief valve
Pressure relief valve is defective.
Replace pressure relief valve.
at rear of freezing chamber.
Heater in freezing chamber
Heater has not been energized at controller.
Energize heater.
does not operate.
Element is faulty.
Replace faulty heating element.
Heater relay is faulty.
Replace faulty heater relay.
Wiring connections are faulty.
Check wiring harness for proper
connector seating at controller.
Models 1010 and 1011 ________________________________________________________________________Maintenance
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