VERDER Carbolite Gero CWF 11/23 Manual

Installation, Operation and Maintenance Instructions
1100°C Chamber Furnace - CWF Model: 23 Litres
No Controller
CWF 11/23 + No Controller
MEN-CWF1123-005_NOCTRL (29-11-2022)

Contents
This manual is for guidance on the use of the Carbolite Gero product specified on the
front cover. This manual should be read thoroughly before unpacking and using the
furnace or oven. The model details and serial number are shown on the back of this
manual. Use the product for the purpose for which it is intended.
1.0 Symbols and Warnings 4
1.1 Switches and Lights 4
1.2 General Warnings 4
1.3 Prerequisites to Use 5
2.0 Installation 6
2.1 Unpacking and Handling 6
2.2 Siting and Setting Up 6
2.3 Chimney 7
2.4 A105 Retort Installation (optional) 9
2.5 Electrical Connections 12
3.0 Temperature Controller 14
4.0 Operation 15
4.1 Operating Cycle 15
4.2 General Operating Notes 15
4.3 Use of Probes and Metal Sheathed Thermocouples 16
4.4 Atmospheres 16
4.5 A105 Retort (optional) 17
4.5.1 Safety Switch Bypass 17
4.5.2 Maximum Operating Temperatures 17
4.5.3 Pressure 18
4.6 Operator Safety 18
4.7 Power Adjustment 19
5.0 Maintenance 20
5.1 General Maintenance 20
5.2 Maintenance Schedule 20
5.2.1 Cleaning 22
5.3 Safety Switch 22
5.4 Calibration 22
5.5 After-Sales Service 23
5.6 Recommended Spare Parts and Spare Parts Kit 23
6.0 Repairs and Replacements 24
6.1 Safety Warning - Disconnection from Power Supply 24
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6.2 Safety Warning - Refractory Fibre Insulation 24
6.3 Temperature Controller Replacement 24
6.4 Solid-State Relay Replacement 25
6.5 Thermocouple Replacement 25
6.6 Panel Element Replacement 26
6.7 Door Plug Replacement 28
6.8 Fuse Replacement 28
7.0 Fault Analysis 30
A. Furnace Does Not Heat Up 30
B. Product Overheats 31
8.0 Wiring Diagrams 32
8.1 WA-U3-30 33
8.2 WA-U3-31 35
9.0 Fuses and Power Settings 37
9.1 Fuses 37
9.2 Power Settings 37
10.0 Specifications 38
10.1 Environment 38
3

1.0 Symbols and Warnings
1.1 Switches and Lights
Instrument switch: when the instrument switch is operated the
temperature control circuit is energised.
Heat light: the adjacent light glows or flashes to indicate that
power is being supplied to the elements.
1.2 General Warnings
DANGER – Electric shock. Read any warning printed next to this
symbol.
WARNING: Risk of fatal injury.
DANGER – Hot surface. Read any warning printed next to this
symbol.
WARNING: All surfaces of a product may be hot.
DANGER – Read any warning printed next to this symbol.
Caution – Double Pole/Neutral Fusing
4

1.3 Prerequisites to Use
Prior to the commissioning and use of this product, all personnel involved in its
installation, operation and maintenance must be deemed competent and have:
lRead and understood the information contained within this manual
lReceived the relevant training with regard to safety and operation of the product
lBeen provided with the appropriate PPE (Personal Protective Equipment) required
for the safe operation of this product
Note: The customer is responsible for ensuring that all of the above conditions are
satisfied before the product is commissioned for use.
Note: Unless otherwise specified, the customer is responsible for the
installation of this product and the safe connection of any additional
equipment and gas or liquid supply lines.
5

2.0 Installation
2.1 Unpacking and Handling
When unpacking and handling the product, always lift it 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 product where possible.
Carefully remove any packing material from inside and around the product before use.
Avoid damaging the surrounding insulation when removing packing materials.
Note: This product contains Refractory Ceramic Fibre (also known
as Alumino Silicate Wool - ASW). For precautions and advice on
handling this material see section 6.2.
2.2 Siting and Setting Up
Place the product on a level surface in a well ventilated area.
Site away from other sources of heat and on a non-flammable surface that is resistant
to accidental spillage or hot materials.
The surface on which the equipment is mounted should be stable and not subject to
movement or vibrations.
The height of the mounting surface is important to avoid operator strain when loading
and unloading samples.
Unless otherwise stated elsewhere in this manual, ensure that there is at least 150
mm of free space around the back and sides of the product. Clear space is required
above the product to dissipate heat.
6

Depending on the application of the product, it may be appropriate to position it under
an extraction hood. Ensure the extraction hood is switched on during use.
Ensure that the product is placed in such a way that it can be quickly switched off or
disconnected from the electrical supply.
Under no circumstances should any objects be placed on top of the
product. Always ensure that any vents on the top of the product are clear
of any obstruction. Always ensure all cooling vents and cooling fans (if
fitted) are clear of any obstruction.
2.3 Chimney
The chimney is a length of tubing. If it is supplied unfitted, then fit it through the hole
in the top of the case.
If the product is to be used to heat substances that emit fumes, a fume extraction duct
of approximately 75 mm - 150 mm inlet diameter may be placed directly above the
chimney outlet.
Do not make a sealed connection to the product chimney as this causes excessive
airflow through the chamber and results in poor temperature uniformity.
7

Key
A Duct (75mm-150mm diameter)
B Ambient air is drawn into duct
C Chimney
D 25mm vertical gap between chimney and duct
8

2.4 A105 Retort Installation (optional)
If the furnace has been ordered with the A105 retort option, it is important that the
retort is correctly installed within the furnace before operation.
Note: Before installing the retort, ensure that all packaging is removed from both
the retort and the furnace.
To install the retort:
lRemove the two bolts and washers from
the front of the furnace shelf, and open
the furnace door.
lCarefully lift the retort and slide it into
the furnace chamber.
Note: The retort is heavy and may require
2 people to lift. Please consult your health
and safety personnel before carrying out
any manual handling procedures.
lEnsure that the two holes in the retort
support bracket align with the holes in
the furnace shelf.
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lSecure the retort in place with the
washers and bolts.
lRemove the two screws to separate the
two sections of the insulated door
surround.
lCarefully slide the top of the door
surround behind the door, until it rests on
the top of the retort.
lCarefully position the bottom section of
the door surround beneath the retort.
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lSecure the two sections of the door
surround together with the two screws.
lUsing a 10 mm spanner and
appropriately-sized cross head
screwdriver, tighten the four long bolts at
either side of the retort.
lConnect the earthing plug from the retort
to the corresponding socket on the side of
the furnace.
Please refer to section 4.5 for details on operating the furnace with the retort installed.
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2.5 Electrical Connections
Connection by a qualified electrician is recommended.
The product covered by this manual normally requires a single phase A.C. supply,
which may be Live to Neutral non-reversible, Live to Neutral reversible or Live to Live.
Some models may be ordered for 3-phase use, which may be with or without neutral.
Check the product rating label before connection. The supply voltage should agree with
the voltage on the label and the supply capacity should be sufficient for the current on
the label.
The supply should be fused at the next size equal to, or higher than the current on the
label. This manual contains a table of the most common fuse ratings.
When the mains cable is factory fitted, internal fuses are also fitted. It is essential that
the operator ensures that the product is correctly fused.
Products with a factory fitted supply cable are designed to be wired directly to an
isolator or fitted with a line plug.
Products without a factory fitted supply cable require a permanent connection to a
fused and isolated supply. The product's electrical access panel should be temporarily
removed, and connections made to the internal terminals.
When connecting the product to the power supply, the plug or isolating switch should
be accessible, easy to remove, and within reach of the operator.
The supply MUST incorporate an earth (ground).
Supply Terminal Label Cable Colour
Supply Types
Live - Neutral Reversible or Live-
Live
1-phase L1 Brown to live
to either power
conductor
(For USA 200-240V,
connect L1)
N / L2 Blue to neutral
to the other power
conductor
(For USA 200-240V,
connect L2)
PE Green/ Yellow to earth
(ground) to earth (ground)
Electrical Connection Details:
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3-phase L1 Black to phase 1
L2 Black to phase 2
L3 Black to phase 3
N Light Blue to neutral (if fitted)
PE Green/ Yellow to earth (ground)
DO NOT connect a product ordered for three phase use to a single
phase supply or to the wrong type of three phase supply.
13

3.0 Temperature Controller
If this product is fitted with a temperature controller, instructions are provided
separately.
14

4.0 Operation
4.1 Operating Cycle
This product is fitted with an instrument switch which cuts off power to the control
circuit.
Connect the product to the electrical supply.
Turn on the instrument switch to activate the temperature controllers. The controllers
illuminate and go through a short test cycle.
Over-Temperature option only. If the digital over-temperature option has not yet
been set as required, set and activate it according to the over-temperature controller
instructions.
The product will heat up according to the controller setpoint or program, unless a time
switch is fitted and switched off.
As the product heats up, the heat light glows steadily at first and then flashes as the
product approaches the desired temperature. For more information on temperature
control see the controller instructions.
Over-Temperature option only. If the over-temperature circuit has tripped, an
indicator on the over-temperature controller flashes and the heating elements are
isolated. Find and correct the cause before resetting the over-temperature controller
according to the instructions supplied.
To turn the product off, set the instrument switch to its off position. The controller
display will go blank. If the product is to be left unattended, isolate it from the
electrical supply.
4.2 General Operating Notes
Heating element life is shortened by overheating. Do not leave the
product at high temperature when it is not required. The maximum
temperature is shown on the product rating label and in section 10.0
towards the back of this manual.
When heating large objects, in particular poor conductors, avoid shielding the
thermocouple from the heating elements. The thermocouple is intended to sense the
temperature near the heating elements. However, if a large object is placed in the
chamber it may record the average temperature of the object and the elements, this
can lead to overheating of the elements. Allow large objects to gain heat at a lower
temperature and then reset the controller to a temperature close to the desired
maximum, or heat using a slowly controlled ramp rate. For more information refer to
the controller instructions.
When heating materials that produce smoke or fumes, the chimney must be correctly
fitted and unobstructed. If not, soot will accumulate in the chamber and could possibly
cause an electrical breakdown of the heating element. If the furnace is used to heat
materials that emit smoke or fumes, regularly heat it up to maximum temperature for
one hour with the chamber empty to burn away the soot.
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Materials such as case hardening compounds and other reactive salts may penetrate
the furnace chamber lining and attack the wire elements, causing premature failure.
Use of a hearth tile may be advisable: please consult the Carbolite Gero technical
department.
4.3 Use of Probes and Metal Sheathed Thermocouples
Any metal object used to probe into the product chamber while the
product is connected to the electrical supply must be earthed. This
applies in particular to metal sheathed thermocouples, where the
sheaths must be earthed. The refractory material of the chamber
lining becomes partly conductive at high temperatures and the
electric potential inside the chamber can be at any value between
zero and the supply voltage. Unearthed probes can cause serious
electric shock.
4.4 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 chamber is not gas tight, the gas usage may be high and the chamber is always
likely to contain some air. Residual oxygen of approximately 1% to 2% is to be
expected.
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4.5 A105 Retort (optional)
Note: Before connecting the product to the electrical supply, the retort
MUSTbe earthed! This product contains ceramic insulation materials
that can become conductive at high temperature. Also, in furnaces with
exposed heating elements, there is a danger of a metal retort directly
coming into contact with the elements. Precautions must therefore be
taken to avoid electric shock.
Note: Retorts are designed for use with inert gas only. The use of
reactive gases will cause damage to the retort and endanger the
operator.
Note: Because the exact details of the customer's process are unknown,
it is not possible to account for process-specific wear to the retort
material. The working life of the retort is variable and depends entirely
on the operating temperatures, program ramp rates, and properties of
the materials being heated. Subsequently the retort is classed as a
consumable item and is not covered by the standard Carbolite Gero
warranty terms.
4.5.1 Safety Switch Bypass
This type of retort requires the furnace to operate with the door open. Where the
furnace normally has door switch(es) which cut off power to the elements when the
door is open, a switch-bypass system is provided.
The retort is fitted with an earth lead terminated in a special plug which mates with a
socket mounted on the furnace. One pin of the plug serves to connect the retort to a
safety earth and the other pins are wired to bridge the door switch contacts. The lead
joining the retort to the plug is short. The plug must be disconnected to permit removal
of the retort from the chamber, thereby restoring the normal operation of the door
switch.
4.5.2 Maximum Operating Temperatures
The maximum operating temperature of the retort is dependent on the retort material.
Retort Material Maximum Operating Temperature
314 Stainless Steel 1050°C
Inconel 601 1100°C
Note: Rapid heating can distort the retort. It is recommended that the heating rate
of the furnace is limited to a maximum of 8°C per minute when using a retort.
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4.5.3 Pressure
The gas supply to the retort should be restricted to a maximum of 200 mbar (0.2 bar /
3 psi). For most processes, the lower pressure of 70 mbar (0.07 bar / 1 psi) should be
sufficient to achieve the required flow rates.
lA suitably regulated gas supply should always be used.
lIt is recommended that a pressure relief system should be used to avoid an over
pressurisation of the retort.
Note: A product should not be heated up if any valves that have been
fitted are closed to create a sealed volume. A sealed retort should not be
heated from cold due to the pressure increase caused by the trapped air
or gas expanding during the heating process.
Note: To minimise the increase of back pressure, always increase the
pipe diameter of any room vent lines when connecting to a product
exhaust outlet. For example, 6mm outlet connections should be
increased to a diameter of 10mm or greater for room lines between 5 -
10 metres in length.
Note: Always maintain clean gas lines. Regularly inspect vent lines
connected to the exhaust outlet as any build up of debris may increase
the back pressure of the retort.
Note: The furnace retort is not designed to operate as a pressure vessel.
To mitigate the risk of pressure build up, before each use, check that the
retort exhaust pipe is free of any obstructions e.g. condensed tar.
4.6 Operator Safety
This product incorporates a safety switch which interrupts the heating
element circuit when the furnace is opened. This prevents the
operator touching a live heating element and also prevents the
product from heating up if the furnace is left open. The operation of
this switch should be checked periodically.
Depending on use, the surfaces in the working chamber and the
chamber load may still be very hot after the appliance is switched off.
Touching these surfaces may cause burns. Use suitable personal
protective equipment or wait until the appliance cools down to
ambient temperature.
Before removing a hot object from the product, make sure there is a safe place to put it
down. If necessary use tongs, face masks and heat resistant gloves. Heat resistant
clothing and face protection can guard against the effects of radiated heat when the
furnace is open.
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When the product is opened during operation there is considerable radiated heat. Do
not keep any flammable objects near the product, nor objects which could be damaged
by radiated heat.
4.7 Power Adjustment
The product control system incorporates electronic power limiting. Depending on the
model and the destination country the power limit maybe set to 100% or a lower
figure. Where appropriate the power limit parameter OP.Hi is accessible to the
operator, but it should not generally be altered.
See section 9.0 for details of the power limit settings. DO NOT adjust the power to a
level higher than the design level states; this may cause a fuse to blow and could
damage the heating elements.
The power limit may be set to a lower limit if the product is to be used at a low
temperature only: this may give better control stability. It may be set to zero to permit
demonstration of the controls without the heating elements taking power; to resume
heating reset it to its standard value.
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5.0 Maintenance
5.1 General Maintenance
Preventive rather than reactive maintenance is recommended. The type and frequency
depends on the product use; the following are recommended.
5.2 Maintenance Schedule
CUSTOMER
QUALIFIED PERSONNEL
DANGER! ELECTRIC SHOCK. Risk of fatal injury. Only electrically
qualified personnel should attempt these maintenance procedures.
Maintenance
Procedure Method
Frequency
Daily Weekly Monthly Bi-
Annually Annually
Safety
Safety Switch Function
Set a safe temperature above ambient,
and open the door to see if the heater
light goes out
Safety Switch Function Electrical measurement
Over-Temperature
Safety Circuit
(if fitted)
Set an over-temperature setpoint lower
than the displayed temperature and
check for an over-temperature alarm as
detailed in this manual
Over-Temperature
Safety Circuit
(if fitted) Electrical measurement
Door Plug Visual inspection, checking the seal and
whether it is free of damage
Door Plug Replacement where necessary
Chimney / Extraction Check and clean if necessary
Electrical Safety
(external) Visual check of external cables and plugs
Electrical Safety
(internal)
Physically check all connections and
cleaning of the power plate area
Function
Temperature Calibration
Tested using certified equipment, fre-
quency dependent on the standard
required
20