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8.3
Safety Warning - Molybdenum Disilicide Elements
Molybdenum disilicide elements form a glazed surface when heated.
Internal stresses can form through heating and cooling which render the
glaze fragile. The glaze can sometimes splinter into a shower of sharp
particles when handled. Always wear eye protection when handling the
elements.
Handle the heating elements with extreme care as they are very fragile. Also, avoid
touching the heating surface (the thin part of the element), as the material is
susceptible to corrosive damage from skin contact.
8.4
Temperature Controller Replacement
Refer to the controller instructions for more information on how to replace the
temperature controller.
8.5
Side Panel Removal
Except where explicitly stated, always disconnect the electrical supply
before removing the side panel.
Remove the panel by loosening the four fixing screws (behind plastic caps) at the left-
hand end of the furnace; do not remove the screws. Lift the panel about 15 mm and
then pull off to the side.
8.6
Thyristor Replacement and Adjustment
Replacement
To replace the thyristor unit, isolate the furnace from the electrical supply and remove
the left-hand side cover. See section 8.5. Make a note of all wiring to the thyristor, then
disconnect it. Replace the unit and connect the wiring again.
Note that the thyristor unit requires replacement if changing from, or to, a 208 V
supply.
If the thyristor unit has been replaced because of a change of voltage, the correct
transformer tapping should also be set. See section 0.1 for panel removal instructions.
8.0 Repairs and Replacements
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