A well-maintained Celsius Wf 604 is a reliable partner in the lab for years to come.
Although not listed in all versions, E-12 typically means communication error between display and main board. Try power-cycling. If persistent, internal ribbon cable may be loose. Celsius Wf 604 User Manual
Before turning on the unit, ensure it is placed on a level surface with adequate ventilation. A well-maintained Celsius Wf 604 is a reliable