Thermo Scientific 3881, Operating And Maintenance Manual

Page: 32 / 60

7033881 Blood Bank 5-1 Thermo Scientific
Section 5
Troubleshooting and Service
The following is a guide for troubleshooting some of the common
problems that may be encountered over the operating life of the
refrigerators. This section is provided as a support to qualified electrical
and refrigeration service.
Symptom Possible Cause/Possible Fix
Refrigerator appears to be completely inoper-
ative; audible alarm is activated and there is
no green light. Power line cord is disconnected.
Power source circuit breaker is open or
source fuse is blown.
Power switch is not turned on (3883, 3887).
High temperature indicator and audible alarm
are activated after the door is opened and
are deactivated shortly after the door is
closed. Alarm system probe is defective.
Note This situation may be normal if the
alarm probe is not immersed in liquid.
Temp control needs adjusted.
Alarm point may need adjusted.
Low temperature indicator and audible alarm
are activated intermittently or continuously.
Chamber temperature is unstable and may
occasionally be below 1.5°C (+/-0.5°C). Refrigeration system temperature controller
may need adjusting.
Alarm point may need adjusted.
Low temperature indicator and audible alarm
are activated intermittently or continuously;
chamber temperature is relatively stable at
4°C. Probe or control board may be defective.
Alarm points may need adjustment.
Possible loose probe wires.