CONTENTS
Section Page
Installation, Operation &
Maintenance Instructions
Clean Room Ovens
CR models
This manual is for the guidance of operators of the above Carbolite products
and should be read before the oven is connected to the electricity supply.
Manuals are supplied separately for the temperature controller
(and overtemperature controller when fitted).
Please read the controller manuals before operating the oven.
MF21 – 3.07
Clean Room Ovens
Instrument switch: when the instrument switch is operated the temperature
control circuit is energised.
DANGER of electrical shock– read any warning printed by this symbol.
DANGER – hot surface. Read any warning printed by this symbol.
WARNING: all surfaces of an oven may be hot.
DANGER – read any warning printed by this symbol.
1.0 SYMBOLS & WARNINGS
1.1 Switches and Lights
1.2 Warning Symbols
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Clean Room Ovens
CONNECTION DETAILS
supply type
Supply
Terminal label
Cable colour
Live-Neutral
Reversible or Live-Live
1-phase
L
Brown
To live
to either power conductor
N
Blue
To neutral
to the other power conductor
PE
Green/Yellow
To earth (ground)
to earth (ground)
supply
Terminal label
Cable colour
3-phase
L1
Black
to phase 1
L2
Black
to phase 2
L3
Black
to phase 3
N
Light Blue
to neutral except delta
PE
Green/Yellow
to earth (ground)
2.0 INSTALLATION
2.1 Unpacking & Handling
Lift the unit by its base. Do not use the door or any other projecting cover or component to support the
equipment when moving it. Use two or more people to carry the oven where possible. Remove any packing
material from the inner chamber before use, and locate the shelves as required.
Larger models: the unit may be lifted by a fork lift truck from the front or back.
NOTE: This product contains Refractory Ceramic Fibre (better described as Alumino Silicate Wool) for
precautions and advice in handling this material see the ‘Repairs and Replacements’ section.
2.2 Siting & Setting Up
Place the oven on a level surface. If overtemperature protection is not fitted, ensure that the unit can be
directly observed.
Ensure that there is free space around the oven. Ensure that any vents in the oven are not obscured.
Ensure that the oven is placed in such a way that it can be quickly switched off or disconnected from the
electrical supply - see below.
2.3 Electrical Connections
Connection by a qualified electrician is recommended.
All ovens covered by this manual may be ordered for single phase A.C. supply, which may be Live to
Neutral non-reversible, Live to Neutral reversible or Live to Live. The 450 litre models and above may be
ordered for three phase supply with neutral (e.g. 380/220V) or for three phase without neutral (delta).
Check the oven rating label before connection. The supply voltage should agree with the voltage on the
label, and the supply capacity should be sufficient for the amperage on the label.
The supply should be fused at the next size equal to or higher than the amperage on the label. A table of
the most common fuse ratings is also given in section 8.1 of this manual. Where a supply cable is present
there are internal supply fuses; customer fusing is preferred but not essential.
Oven with supply cable: either wire directly to an isolator or fitted with a line plug.
Oven without supply cable: a permanent connection to a fused and isolated supply should be made to the
internal terminals after temporary removal of the back panel.
Connection by line plug: the plug should be within reach of the operator, and should be quickly removable.
Connection to isolating switch: this should operate on both conductors (single phase) or on all live
conductors (three phase), and should be within reach of the operator.
The supply MUST incorporate an earth (ground).
DO NOT connect an oven ordered for three phase use to a single phase supply or to the wrong type
of three phase supply.
MF21 – 3.07
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Clean Room Ovens
3.0 OPERATION
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.
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, always investigate the possibility that the main control system
has failed.
An overtemperature condition always 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 with the stoving and curing option.
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. 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.
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Clean Room Ovens
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.
MF21 – 3.07
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