Carbolite BLF 18/21 - Manual (Page 10)

BLF
10
MF23 – 3.11
5.6 Element Installation & Replacement
Safety Warning – Molybdenum Disilicide elements.
The 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.
Remove the element access cover (see section 2.3).
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 new 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 slide over
them the insulation blocks. Fix the clamps so that the length of element leg above them is 30mm
(most models) or 45mm (BLF 17/8).
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 run the furnace at 1500°C for an hour. This creates a protective glaze
on the element surface.
Use of Clip Tool
larger clips require clip tool, comprising
two levers
smaller clips do no require clip tool