Carbolite CR Series - Manual (Page 5)

Clean Room Ovens
MF21 – 3.07
5
3.5 Variable Speed Fan Option
When this is ordered, or in any model where it is supplied as standard, a variable speed control is
fitted in the fan circuit. Operation of the rotary 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 inside the oven.
3.6 Fan Exhaust and Moisture Extraction Options
When one of these options is fitted the motor and fan box and outlet vent are on the top of the unit,
adding 450mm height. The outlet vent is a 64mm o/d tube to which suitable ducting can be
connected if required.
Please note that the heater element power rating may be increased; check the oven rating label for
power and fuse requirements.
Start the extraction unit using the amber switch on the control panel; this is only functional when
the instrument switch is on.
The amount of air exhaust can be controlled by adjusting the vent control slider beneath the
exhaust fan box.
When the unit is turned on, there may be a drop in internal temperature before the oven recovers to
the setpoint value.
3.7 Stoving and Curing Option
The oven is fitted with an explosion relief panel and a powered exhaust fan. The exhaust fan is
physically similar to that described above.
With this option the fan runs all the time that the oven is switched on.
A pressure switch detects that there is sufficient air flow through the chamber, and prevents the
oven from heating if the exhaust fan is not working correctly. If the pressure switch does not detect
sufficient air flow, a fault light comes on and the oven is prevented from heating up.
At least 200mm free space must be left at the back and side of the oven to allow the explosion
relief panel to break out if there is a rapid build up of pressure inside the chamber.