EF, AF
8
LF01
5.0 R
EPAIRS
& R
EPLACEMENTS
5.1 Safety Warning – Disconnection from Supply
Always ensure that the furnace is disconnected from the supply before repair work is
carried out.
5.2 Safety Warning - Refractory Fibrous Insulation
This furnace contains refractory fibres in its thermal insulation. These materials may
be in the form of fibre blanket or felt, vacuum formed board or shapes, mineral wool
slab or loose fill fibre.
Normal use of the furnace does not result in any significant level of airborne dust from these
materials, but much higher levels may be encountered during maintenance or repair.
Whilst there is no evidence of any long term health hazards, we strongly recommend that safety
precautions are taken whenever the materials are handled.
Exposure to dust from fibre which has been used at high temperatures may cause
respiratory disease.
When handling fibre always use an approved mask, eye protection, gloves and long
sleeved clothing.
Avoid breaking up waste material. Dispose of waste fibre in sealed containers.
After handling rinse exposed skin with water before washing gently with soap (not
detergent). Wash work clothing separately.
Before commencing any major repairs we recommend reference to the European Ceramic Fibre
Industry Association Bulletin No. 11 and the UK Health and Safety Executive Guidance Note
EH46.
We can provide further information on request. Alternatively our service division can quote for
any repairs to be carried out at your premises or ours.
5.3
Temperature Controller Replacement
2216, 2416, 2408 etc. Ease apart the two lugs at the side; grip the instrument and withdraw it from
its sleeve; push in the replacement.
5.4
Solid-state Relay Replacement
Disconnect the furnace from the supply and remove the control panel.
Make a note of the wire connections to the solid state relay, and disconnect them.
Remove the solid state relay from its panel or base plate.
Replace and reconnect the solid state relay ensuring that the heat-conducting thermal pad is
sandwiched between the relay and the panel or plate. Alternatively a thin layer of white, heat-
conducting silicon paste may be applied between the new relay and the base.
The new solid state relay contains a built-in MOV which protects it from short periods of excess
voltage. If the old relay had a separate disc-shaped "MOV" connected between the high voltage
terminals of the old relay, discard the old MOV.
Replace the removed panel.
5.5 Fuse Replacement
Fuses are marked on the circuit diagram (section 7.1) with type codes, e.g. F1, F2. A list of the
correct fuses is given in section 0.
Fuse types F2 and F3 may not be fitted on this furnace
.
If any fuse has failed, it is advisable for an electrician to check the internal circuits.
Summary of Contents for Lenton AF 11/6
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