background image

 
 1700-1800° 

Chamber 

 

 

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 

 

2132, 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  Fuse Replacement 

 

Access to internal fuses is by removal of the furnace cover or back panel. See section 8.1 for 
details of fuses fitted.  

5.5 

Thermocouple Replacement 

 

Disconnect the furnace from the supply, and remove the furnace cover or back panel. 

 

Make a note of the thermocouple connections.

 

The negative leg of the thermocouple is marked 

blue.

 

The “compensating” cable for 1700 & 1800°C thermocouples is plain copper. 

 

Disconnect the thermocouple from its terminal block. 

 

Bend the metal tag, or release the screw, to release the thermocouple sheath; withdraw the sheath, 
and shake out any fragments of thermocouple. 

 

Re-assemble with a new thermocouple observing the colour coding, ensuring that the 
thermocouple is not twisted as it is being inserted and that the metal tag is bent back, or the screw 
inserted, to grip the sheath. 

5.6 

MF22 

Summary of Contents for HTF 18/15

Page 1: ...nnected to the electricity supply CONTENTS Section page 1 0 Symbols Warnings 2 2 0 Installation 3 3 0 Operation 5 4 0 Maintenance 8 5 0 Repairs Replacements 8 6 0 Fault Analysis 12 7 0 Circuit Diagram...

Page 2: ...glows Heat Light the adjacent light glows or flashes to indicate that power is being supplied to the elements 1 2 Warning Symbols DANGER of electrical shock read any warning printed by this symbol DA...

Page 3: ...there is free space around the furnace Do not obstruct any of the vents in the case there are cooling fans in the case which must not be obstructed Ensure that the furnace is placed in such a way that...

Page 4: ...nual In some models supply cables are fitted as are internal supply rated fuses The cable may be directly wired to an isolator or fitted with a line plug The supply point must be within reach of the f...

Page 5: ...d Find and correct the cause before resetting the overtemperature controller according to the instructions supplied To switch the furnace off set the Instrument switch to off The case cooling fans rem...

Page 6: ...hearth can be protected from abrasion if required by the provision of a secondary plate This consumable item can either be in light weight ceramic fibre or in dense hard wearing alumina refractory 3...

Page 7: ...by a calibration test or by comparing the output with a new reference thermocouple which has been subjected to high temperatures for a minimum length of time Failure to check the thermocouple may res...

Page 8: ...ont of this booklet when supplied with a furnace To contact Thermal Engineering Services or Carbolite see the back page of this manual 4 4 Recommended Spares Kits Carbolite can supply individual spare...

Page 9: ...rately 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 pro...

Page 10: ...ponents and the support system appropriate to your furnace There are also variations in the positions of the braids which connect the elements the rule is that for single phase all elements are in ser...

Page 11: ...ler clips do no require clip tool Element Data distance from top of element clamp to top of element RHF 17 3 RHF 17 10 32mm RHF 17 25 HTF 18 3 47mm HTC 18 8 45mm HTF 18 15 40mm HTF 18 27 40mm Element...

Page 12: ...controller may be faulty or not receiving a supply due to a faulty switch or a wiring fault The SUPPLY light is OFF Check the supply fuses and any fuses in the furnace control compartment B Furnace O...

Page 13: ...ansformer may be fitted 2 Door actuator circuits may differ from the example shown 7 2 Three Phase Models Each set pair of elements has its own transformer controlled by a thyristor complete with thyr...

Page 14: ...1700 1800 Chamber 14 MF22...

Page 15: ...troller OP Hi should be 100 for all models The thyristor stacks are set to the secondary element maximum currents given in the table TABLE OF FUSE AND CURRENT LIMIT VALUES Model Phases volts supply fu...

Page 16: ...g the details below UK Office Keison Products P O Box 2124 Chelmsford Essex CM1 3UP England Tel 44 0 330 088 0560 Fax 44 0 1245 808399 Email sales keison co uk Please note Product designs and specific...

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