33
Preventive Maintenance
Warning
Before
using
any
cleaning
or
decontamination method except those
recommended by Thermo Scientific,
users should check with Thermo
Scientific that the proposed method
will not damage the equipment.
Warning
Disconnect the furnace from power
supply before cleaning.
Warning
Opening the door for an extended
period of time will cause the painted
surfaces above the door to be
discolored or burnt.
Contamination is a major cause of element failure, there-
fore, when possible, remove the fume forming material
before heating (e.g., cleaning cutting oil from tool steel).
The resistance wire is high-grade nickel-chromium. Some
chemicals, notably sulphur, halogens, and cyanides,
attack this wire at high temperatures, so avoid spilling
these chemicals in the furnace or heating them any hotter
than necessary. The refractory cement helps to protect
the wire, but will not completely immunize it from damage.
All heating elements must be considered expendable, and
replacement is expected; however, reasonable care in
their use will greatly extend the service they will give. As
the manufacturer has no control over the use or care of
the elements, no specific service guarantee can be made.
Housekeeping is vital to your electric furnace
—KEEP IT
CLEAN! Run your furnace up to 871°C (1600°F) empty
occasionally to burn off the contamination that may exist
on the insulation and elements. Run for approximately two
hours with the door slightly open. See warning.
Element life is reduced somewhat by repeated heating
and cooling. If the furnace is to be used again within a
few hours, it is best to keep it at the operating
temperature or at a reduced level such as 260°C
(500°F).
During normal use, the thermocouple in your furnace can
become oxidized and cause inaccurate readings; there-
fore, we suggest that if you regularly use your furnace you
should change your thermocouple once every six months
to assure the accuracy of your controller readings.
Clean by wiping the outside case of the unit with a damp
cloth and mild soap solution.
