Carbolite VST Series - Manual (Page 10)

HST, VST
10
MF13 – 3.40
5.7 Element Replacement
Please see safety note 5.2 - please wear a face mask.
HST, and VST with far hinge: Remove the three screws from each end and lift out the half-circular
insulation assembly.
Make a plan of all the cable connections and disconnect the cables.
Remove the thermocouple(s) by withdrawing them from the sheaths built into the elements.
Remove the plates through which the element tails are located. Remove the keep plates from each
side of the insulation assembly.
Lift out the element to be replaced; save any insulation sleeves for possible reuse.
Bend or cut the new element tails as necessary, and fit any insulation sleeves; feed the tails through
and fit the element into place.
Refit the keep plates on each side. Refit the tail termination plates, ensuring that the element tails
do not touch any metal parts. Refit the thermocouple(s).
Connect all the wiring according to the plan previously made, and complete the reassembly of the
furnace.
Check that the furnace is controlling properly to rule out the possibility that the element failed
because of a fault in the control system.
HST & VST Elements
each element is a half-cylinder
HST & VST 12/200 200-240V 1 pair of 200mm
elements in series 100-120V 1 pair of 200mm
elements in parallel
HST & VST 12/300 200-240V 2 pairs of 150mm
elements in parallel,
each pair in series 100-120V 2 pairs of 150mm
elements in parallel
HST & VST 12/400 200-240V 2 pairs of 200mm
elements in parallel,
each pair in series 100-120V 2 pairs of 200mm
elements in parallel
HST & VST 12/500 200-240V 2 pairs of 150mm
elements in parallel,
and 1 pair of 200mm
elements in parallel,
each pair in series 100-120V 2 pairs of 150mm and
1 pair of 200mm
elements in parallel
HST & VST 12/600 200-240V 3 pairs of 200mm
elements in parallel,
each pair in series 100-120V 3 pairs of 200mm
elements in parallel
HST & VST 12/900 200-240V 2 pairs of 150mm
elements in parallel,
and 3 pairs of 200mm
elements in parallel;
each pair in series 100-120V 2 pairs of 150mm and
3 pairs of 200mm
elements in parallel
Wherever two different sizes of elements are fitted, the 150mm elements are at the ends and the
200mm elements in the centre.