6.9
Element Installation and Replacement
See section 6.3 - Safety Warning - molybdenum disilicide.
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.
Remove the element access cover (see section 2.1).
Remove the aluminium braids and clips using fingers or the clip tool provided,
depending on the type of clip (or remove the combined clips and braids, if supplied).
Lift out the old element and the insulation block: handle the block with care as it is
fragile. Remove the clamps.
Handle the heating elements with extreme care as they are VERY FRAGILE. Also, avoid
touching the heating surface (the thin part of the element).
Carefully unpack the elements and insert them into the insulation blocks. Fix the
clamps 45 mm (BLF 17/8) or 30 mm (all other models) from the end of the element as
shown in the image below.
Insert the new element; refer to the element connection diagram. Single phase models
have all the elements connected in series. Reconnect the braids. Ensure that no braids
of clips are touching each other or touching any other furnace parts.
After installing new elements operate the furnace at 1500 °C for an hour. This creates a
protective glaze on the element surface.
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