Carbolite HTMA Series - Manual (Page 5)

High Temperature Ovens
MF16 3.09
5
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. In the LHT models the
case cooling fans operate when the instrument switch is 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 only. 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 begins 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.
DO NOT switch off if the temperature is above 300°C - damage could be caused to the fan and
motor. Adjust the controller or the overtemperature controller to allow the temperature to fall.
3.2 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.
3.3 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 specially for the purpose.
3.4 Atmospheres (only applies to LHT and HT models)
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.