Carbolite GPC Series - Manual (Page 6)

GPC
6
MF04 3.29
3.4 Atmospheres
When an optional gas inlet is fitted there is a label near the inlet saying "INERT GAS ONLY". In
practice inert or oxidising gases may be used, but not combustible or toxic gases. Chamber
furnaces are not gas tight, so it should be understood that gas usage may be high, and that the
chamber is likely always to contain some air. Residual oxygen levels 1% are to be expected.
If a metal retort is supplied with this furnace, please see the supplementary manual MS05.
3.5 Operator Safety
The furnace incorporates a safety switch which interrupts the heating element circuit when the
door is opened. This prevents the user touching a live heating element, but also prevents the
furnace from heating up if the door is left open. The operation of this switch should be checked
periodically – see section 4.1.2.
Avoid burns: furnace surfaces can be hot. Before you remove a hot object from the furnace make
sure you have a safe place to put it down.
3.6 Power Adjustment
The furnace control system incorporates electronic power limiting. The power limit parameter
OP.Hi may be accessible to the operator, but should not generally be altered.
A table of the correct power limit values is given in section 8.2. Note that in GPC models the
standard value is in many cases not 100%.
The power limit may be set to a lower limit if the furnace is to be used at a low temperature only:
this may give better control stability. It may set to zero to permit demonstration of the controls
without the heating elements taking power; to resume heating reset it to its standard value.