7-2
Hotplate & Magenetic Stirrer
Thermo Scientific
Section 7
Troubleshooting
Problems During Operation
Cause
Corrective Action
No heat
Failure to push RUN/STOP button
Push RUN/STOP button.
Set point value is lower than present
temperature value.
Adjust Set point lower than Present
temperature value.
Power cut-off by built-in overheat
prevention circuit
Turn off the main power switch and wait
until the heater cools down. Then, turn
on the main power switch.
Internal circuit failure
Contact Thermo Scientific for service
Button switch failure
Contact Thermo Scientific for service
No or too slow temperature change
during heating
Probe is not enough soaked into the media.
Soak probe into the media more than
20mm of it.
Too low setting of the heating level
Turn the heater knob clockwise to
increase the heating level
Too much media
Reduce the media volume.
Internal circuit failure
Contact Thermo scientific for service.
Stir bar decoupling
Too much media
Reduce the media volume or increase
the rpm more gradually.
High viscosity of the media
Increase the rpm more gradually or
change the stir bar with a small friction
resistance one (ex. cone type).
Decreased magnetic strength of stir bar
Replace the old stir bar with a new one.
Knocking noise during stirring
Uneven bottom of the vessel
Use a vessel with thin, flat bottom.
Loosened internal parts
Contact Thermo Scientific for service.
Abnormal speed control operation
Too much media
Reduce the media volume.
Internal circuit failure or damaged motor
Contact Thermo Scientific for service.
Knob malfunction
Damaged knob
Take out the knob and relocate it.
Contact Thermo Scientific for service.
LED display malfunction
Damage due to chemical spill or overheat
Contact Thermo Scientific for service.
Probe lamp is not ON
Probe connection failure.
Reconnect probe in right way.
Damage due to chemical spill or overheat.
Contact Thermo Scientific for service.
