7.0 Repairs and Replacements
7.7
Solid-state Relay Replacement
Disconnect the product from the power supply and remove the
appropriate cover as given above.
1. Make a note of the wire connections to the solid state relay, then disconnect them.
2. Remove the solid state relay from the base panel or aluminium plate.
3. Replace and reconnect the solid state relay ensuring that the bottom of it has good
thermal contact with the base panel or aluminium plate.
4. Replace the access panel.
7.8
Element Replacement
The inside of the chamber is made up of four heating panels, one for each wall. The
heating panels consist of wire elements embedded in refractory cement. The
connections are located at the bottom of the insulation assembly, with access to them
through the base of the furnace case.
Disconnect the furnace from the supply. Lift up the door and ensure that it is safely held
open.
Remove the top panel. The removable part of the frame on the left may need tobe
removed.
Remove the left panel.
Inside the left hand side, observe that the inner chamber ("brick box") has a removable
side; loosen this side - it should not be necessary to remove it completely.
Turn the furnace onto its back and remove the bottom panel.
Make a written plan showing ALL the element and thermocouple connections. It is
important to make this plan for each individual furnace.
Disconnect all the element wire tails and thermocouple cables from their terminal
blocks.
Straighten all the element tails. Note that these become brittle with use.
Working from the top, ease the failed slab element(s) out. The element slabs may have
become fused together, it may be difficult to remove an individual slab.
Insert the new element(s), carefully threading the tails through the terminal blocks. Cut
off excess tails and re-tighten. Remake all connections according to the plan previously
made.
Tighten the loosened panel of the brick box.
Refit all panels and return the furnace to the vertical position.
Run the furnace for 30 minutes at 800 °C without interruption to ensure complete burn-
off of any organic binders. This procedure should be carried out in a well ventilated
room as this process will produce smoke.
Check that the furnace is controlling properly to rule out the possibility that the previous
element failed because of a fault elsewhere in the control circuit.
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Summary of Contents for CARBOLITE GERO VCF 12/10
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