News and Announcements
Warning about malfunctioning hotplates
Newer models with TRIAC or microprocessor-controlled heater switches may spontaneously heat when liquid comes into contact with the electronics.
A related problem is the malfunctioning of external temperature probes that cause the hotplate to heat excessively.
DRS recommends the following to prevent accidents caused by hotplate overheating:
- Discard hotplates purchased prior to 1984 and hotplates in disrepair.
- Periodically test the function of the off switch to verify that it works and the heating device quickly cools. If the device fails the test, take it out of service immediately.
- Unplug hotplates when not in use.
- If only stirring is required, use a stirrer only, not a hotplate/stirrer combination.
- When acquiring new hotplates, select a housing design that is hermetically sealed to protect electronics from liquids and gases. In addition look for two independent temperature control circuits that shut off power when the temperature exceeds a selected limit.
- If an external probe begins to show occasional malfunctioning such as temperature deviation or fluctuations, take it out of service immediately as it will fail sooner or later.
- Safety Issues of Hotplate Heating Controls, poster from Northwestern University
- Deflagration and Fire from Malfunctioning Lab Stirrer/Hot plate , Oak Ridge National Laboratory, June, 2014
- Hotplate Advisory! , MIT, 2010
- Hot Plate Switch Failure, Lawrence Berkeley National Laboratory Lessons Learned, 2005
- Hot Plate and Heating Device Safety Advisory, University of California, 2011