Carbolite GP Series - Manual (Page 4)

GP Ovens
4
MF17 3.07
3.0 O PERATION
The instructions for operating the temperature controller are given in a separate manual.
If the oven is fitted with a time switch, see also the supplementary manual MS03.
If cascade control is fitted, see the supplementary manual MS07.
If the oven has variable speed fan, air extraction or stoving and curing options, please also see the
appropriate section on the next page of this manual.
3.1 Operating Cycle
The oven is fitted with an instrument switch. The switch cuts off power to the controller(s).
The circulation fan operates when the instrument switch is switched on.
Connect the oven to the electrical supply.
Operate the instrument switch to activate the temperature controller. The controller becomes
illuminated and goes through a short test cycle.
Adjust the temperature controller – see the controller manual.
Overtemperature Option: If the overtemperature controller has not yet been set as required, set it
and activate it according to the instructions in the appropriate manual.
Unless a time switch is fitted and is off, the oven starts to heat up according to the controller set
point or program.
To turn the oven off, set the Instrument switch to it’s off position; the controller display will go
blank. If the oven is to be left off unattended, isolate it the electrical supply.
2.2 Overtemperature Control (if fitted)
The overtemperature controller should typically be set at 15°C above the main controller. If an
overtemperature condition occurs, check the possibility that the main control system has failed.
An overtemperature condition cuts off power to the heating elements. It is indicated by a light in
the overtemperature controller flashing. To reset the condition, either allow the oven to cool, or
increase the overtemperature setting, then follow the instructions in the appropriate manual.
3.2 Explosive Vapours
The standard models are not suitable for drying or heat treatment applications where vapours are
released which are combustible or which can form explosive mixtures with air. For such
applications only use models supplied with the stoving and curing option.
3.3 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. The oven
chambers 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 of 1% are to be expected.
3.4 Variable Speed Fan Option
When this is ordered, a variable speed control is fitted in the fan circuit. Operation of the control is
self-explanatory.
Please note that there is a minimum setting at which the fan motor starts up when the oven is
switched on. Find this setting by experiment, and mark the position on the control or front panel.
It is unlikely that a control setting of less than 50% would ever be required, as there would be very
little air flow around the oven.