Thermo Scientific Revco RDE Series Installation And Operation Manual page 23

Problem
Problem with temperature
validation/calibration.
Unit is constantly alarming.
Unit cycle on-percentage is
increasing (Compressors are
running more often than
before).
Difficult to close / open the
outer door.
Outer door alignment issues.
Difficult to close / open the
inner door.
Vibration noise.
Rattling noise/ Loud noise.
Thermo Fisher Scientific ULT Freezers
Cause
Cabinet temperature
displayed doesn't match
with actual temperature.
Exterior door is closed but
not sealed completely.
Door open alarm, exterior
door not closing
completely.
Door open alarm, exterior
door is closed but not
sealed completely.
Alarm set points may have
changed.
Ambient conditions.
Warm load (or) over load.
Frequent and prolonged
door openings.
Unit is not level.
Frost accumulated on
outer door gasket.
Door latch problem.
Frost accumulated around
inner door.
Inner door latches
damaged.
Unit is not level.
Loose side panels.
Rubber tubing separators
and/or compressor
dampeners may have
loosened.
Solution
Customers performing on-site temperature calibration
may observe as much as a 2°C variation when an external
probe is placed next to the freezer control probe. This
variation is normal due to optimisation of the control
system to ensure temperature uniformity throughout the
cabinet.
Clean any ice build-up on gasket and/or cabinet surface.
Check for punctures or tears on gasket.
Open door completely and immediately close and latch it.
Defrost exterior door gasket and make sure the door is
completely sealed.
Change the set points as required.
Unit performance is directly impacted by these causes
mentioned. Try maintaining ambient conditions, reducing
load, reducing door openings.
Once temperature is stable, cycle dynamics should return
to normal range. If not call service.
Make sure the unit is level.
Refer Leveling in the user manual for levelling procedure.
Scrape the ice occasionally on outer gasket.
Do not puncture gasket.
Ensure door latch is securing. If issue persists, call
service.
Remove frost or ice build-up from inner door assembly.
Call service.
Check if the unit is installed in a level area free from
vibration. (Refer Leveling in user manual)
Check side panel screws, tighten them if necessary.
Call service.
Troubleshooting Guide | 19