When the product is opened during operation there is considerable radiated heat. Do
not keep any flammable objects near the product, nor objects which could be damaged
by radiated heat.
6.3
Loading The Furnace
When heating large objects, in particular poor conductors, avoid shielding the
thermocouple from the heating elements. Also ensure that nothing is within 15 mm of
the elements.
The thermocouple is intended to sense the temperature near the heating element.
However if a large object is placed in the chamber it may record the average
temperature of the object and the elements, which can lead to over heating of the
elements. Allow large objects to gain heat at a lower temperature and then reset the
controller to a temperature close to the desired maximum.
Take care that nothing hits the elements when loading and unloading.
6.4
Opening the Door
Take great care when loading or unloading the furnace chamber. See
section 6.2. Before removing a hot object from the furnace, ensure a
suitable surface is available on which to put it.
Do not open the door at high temperatures. If possible, do not open it above 200 °C. If
it is necessary to load or unload work at elevated temperatures, keep the door open for
as short a period as possible. The insulation cools quickly and may crack through
thermal shock.
The heating elements and the insulation are very susceptible to mechanical shock. At all
times operate the door gently to avoid mechanical shock.
Opening the door when the furnace is very hot can cause hot air to be sucked by the
case cooling fans towards the thermal cut out and activate it (see section 6.11). Avoid
excessive door opening and shut it as soon as possible.
6.5
Insulation Cracking
In these furnaces the insulation material is susceptible to surface cracking as a result of
high temperature cycling; this is a normal occurrence and such cracking is not
detrimental to the performance of the furnace.
6.6
Atmospheres & Corrosive Materials
In oxidising atmospheres, metal oxides react with the silica layer on the surface of the
elements and may lead to premature failure. Protect the elements from splashes of
molten metal and dust when loading the furnace and from fumes developed when
melting, especially from fluxes. Also avoid compounds with a high alkali content.
The furnace is designed for use up to its maximum temperature in oxidising
atmospheres, but can be operated successfully in neutral or carburising atmospheres. It
43
6.0 Operation
Summary of Contents for CARBOLITE GERO HTF 18/8
Page 7: ...Caution Double Pole Neutral Fusing 7 1 0 Symbols and Warnings ...
Page 37: ...Power Limit View 37 4 0 3508 Dual Loop Cascade ...
Page 59: ...59 8 0 Repairs and Replacements ...
Page 64: ...10 0 Wiring Diagrams GR Y Green Yellow 64 ...
Page 68: ......
Page 69: ...Notes Service Record Engineer Name Date Record of Work ...
