VERDER Carbolite Gero CTF 12/100/900 Manual

Installation, Operation and Maintenance Instructions
1200°C Tube Furnace - CTF Model: 900mm
No Controller
CTF 12/100/900 + No Controller
MEN-CTF12100-05_NOCTRL (02-01-2018)

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
2.0 Installation 6
2.1 Unpacking and Handling 6
2.2 Siting and Setting Up 6
2.3 Tube Fittings 7
2.4 Electrical Connections 8
3.0 Temperature Controller 10
4.0 Operation 11
4.1 Operating Cycle 11
4.2 General Operating Advice 11
4.3 Operator Safety 12
4.4 Tube Life 12
4.5 Pressure 12
4.6 Power Adjustment 13
4.7 Running at Low Temperatures 13
5.0 Maintenance 14
5.1 General Maintenance 14
5.1.1 Cleaning 14
5.2 Calibration 14
5.3 After-Sales Service 14
5.4 Recommended Spare Parts and Spare Parts Kit 14
6.0 Repairs and Replacements 15
6.1 Safety Warning - Disconnection from Power Supply 15
6.2 Safety Warning - Refractory Fibre Insulation 15
6.3 Temperature Controller Replacement 15
6.4 Solid-State Relay Replacement 16
6.5 Thermocouple Replacement 16
6.6 Fuse Replacement 16
6.7 Element Replacement 18
7.0 Fault Analysis 19
2

A. Furnace Does Not Heat Up 19
B. Product Overheats 20
8.0 Wiring Diagrams 21
8.1 WA-11-30 21
8.2 WA-11-31 22
8.3 WA-22-30 23
8.4 WA-22-31 23
9.0 Fuses and Power Settings 24
9.1 Fuses 24
9.2 Power Settings 24
10.0 Specifications 25
10.1 Environment 25
3

1.0 Symbols and Warnings
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.
Heat switch: the switch disconnects power to the heating elements;
unless this switch is OFF there is a danger of electric shock when
inserting objects into the product.
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.
4

Caution – Double Pole/Neutral Fusing
5
1.0 Symbols and Warnings

2.0 Installation
2.0 Installation
2.1 Unpacking and Handling
When unpacking or moving the product always lift it by its base or by both ends of the
main body. Never lift it by its work tube or the surrounding insulation. Use two or more
people to carry the product and control box. Remove any packing material from inside
the product before use.
If an optional or special stand is separately supplied, assemble the product on to it.
Some models may be supplied for customer mounting and may require customer
preparation of mounting components before installation.
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.
Ensure that there is free space around the sides and back of the product. Clear space is
required above the product to dissipate heat.
Ensure that the product is placed in such a way that it can be quickly switched off or
disconnected from the electrical supply.
A product ordered for vertical use has a small clip or plate at one end to prevent a
wound tube element or a work tube from slipping downwards.
Mount the product so that this clip is at the bottom. In models with one thermocouple
the thermocouple should be near the top rather than the bottom.
If the product is supplied with a separate work tube or any accessories fit these into
position.
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.
6

2.3 Tube Fittings
For optimum temperature uniformity, insulating plugs should be placed in the tube ends
as shown in fig.1. With a long work tube, the stem of the plug assembly should line up
with the end of the tube as in fig.2. Alignment of radiation shields is similar to that of
plugs.
If stainless steel seals with gas inlets are supplied, they are to be fitted as shown in
fig.3; the stem of any insulating plug should touch the seal.
For vertical models with stainless steel seals, a hook and eye arrangement holds the
upper insulating plug assembly.
Horizontal models: if heavy fittings are to be clamped to the end of an extended work
tube they can increase the bending stress at the centre of the tube. Support such
fittings in such a way that expansion of the tube is allowed.
Fig 1 - Insulating Plug
(standard length tube)
Fig 2 - Insulating Plug
(long work tube)
Fig 3 'Twin Clamp' End Seal
7
2.0 Installation

2.0 Installation
For assembly details refer to the separate work tube end seal manual.
2.4 Electrical Connections
Connection by a qualified electrician is recommended.
The product 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. This
model can be supplied for use on two phases of a three phase with neutral supply (one
phase unused).
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. A table of the most common fuse ratings is also given towards the back of this
manual. 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 should be made to the internal terminals after temporary
removal of the product's electrical access panel.
If the product is to be connected by line plug. The plug should be within reach of the
operator and should be easy to remove.
When connecting the product to an isolating switch ensure that 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).
8

Supply Terminal Label Cable Colour
Supply Types
Live - Neutral Reversible or Live-
Live
1-phase L Brown to live
to either power
conductor
(For USA 200-240V,
connect L1)
N 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:
2- or
3-phase L1 Black to phase 1
L2 Black to phase 2
L3 Black to phase 3 (except 2-phase)
N Light Blue to neutral (except delta)
PE Green/ Yellow to earth (ground)
DO NOT connect an model ordered for three phase use to a single phase supply or to
the wrong type of three phase supply.
9
2.0 Installation

3.0 Temperature Controller
3.0 Temperature Controller
If this product is fitted with a temperature controller, instructions are provided
separately.
10

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.
There is also a heater switch which can be used to disconnect power to the elements.
Operate the instrument switch to activate the temperature controller. The controller
becomes illuminated and goes 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 switch off power to the heating elements, use the heater switch. To switch the
product off, use both the heater switch and the instrument switch. If the product is to
be left switched off and unattended, isolate it from the electrical supply.
4.2 General Operating Advice
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.
Lightweight ceramic fibre insulation can easily be marked by accidental
contact. Some fine cracks may develop in the surface of the insulation
due to the progressive shrinkage of the insulation materials. Cracks are
not usually detrimental to the functioning or the safety of the product.
11
4.0 Operation

4.0 Operation
4.3 Operator Safety
The ceramic materials used in the product manufacture become
electrically conductive to some extent at high temperatures. DO NOT use
any conductive tools within the product without isolating it. If a metal
work tube is used, it must be earthed (grounded).
Switch off the heater switch whenever loading or unloading the product.
The elements are isolated when the heater switch is OFF. This switch
cuts both sides of the circuit via a contactor.
4.4 Tube Life
A ceramic work tube may crack if work pieces are inserted
too quickly or at temperatures below 900 °C (when the
tube is more brittle). Large work pieces should also be
heated slowly to ensure that large temperature
differences do not arise.
Poor thermal contact should be encouraged between the
work piece and the tube; crucibles or boats should be of
low thermal mass and should have feet to reduce the
contact with the tube (fig. 4).
Do not set too high a heating or cooling rate. As tubes are susceptible to thermal shock
and may break. Tubes which extend beyond the heated part of the furnace are more at
risk. A general rule for maximum heating or cooling rate is 400 ÷ internal diameter in
mm to give (°C/ min); for 75 mm i/ d tubes this comes to 5 °C per minute. The
controller can be set to limit both the heating and cooling rate.
4.5 Pressure
Work tubes are not able to accept high internal pressure. When gas seals or similar
fittings are in use, the gas pressure should be restricted to a maximum of 0.2 bar (3
psi). A pressure of approximately half of that should normally be sufficient to achieve
the desired flow rate. The operator must ensure that the exhaust path from the tube is
not blocked, so that excess pressure does not occur.
A suitably regulated gas supply should always be used.
It is recommended that a pressure relief system should be used to avoid an over
pressurisation of the work tube.
Please note: A product should not be heated up if any valves that have been fitted are
closed to create a sealed volume. A sealed work tube should not be heated from cold
due to the pressure increase caused by the trapped air or gas expanding during the
heating process.
12

4.6 Power Adjustment
The product control system incorporates electronic power limiting. The power limit
parameter OP.Hi is accessible to the operator and can be used to adjust the product to
the actual supply voltage.
Some models covered by this manual are fitted with 208 V elements and are designed
for use over the range of voltages 200 V- 250 V; the power limit parameter is set
accordingly. These models may be relocated to a different voltage within the range: the
power limit should be reset to match the voltage.
To check whether the furnace is a 208 V model:
llook at the OP.Hi parameter
lmake a note of the value and compare with the 9.0;
lobserve the rating label; if a range of voltages is stated, it is not a 208 V multi
voltage model;
lif in doubt, check with Carbolite Gero – each product has its own record card.
Refer to the controller instructions for how to change the power limit.
4.7 Running at Low Temperatures
The power limit may be adjusted to a low level in order to achieve better control when
operating the product at a low temperature. Before changing the power limit, record
the default settings for possible future use. Refer to section 0.1 for default power limit.
If the product fails to reach the desired temperature, refer to sections 3.0 and 1.0.
13
4.0 Operation

5.0 Maintenance
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.
5.1.1 Cleaning
Soot deposits may form inside the furnace, depending on the process. At appropriate
intervals remove these by heating as indicated in the General Operation Notes.
The product's outer surface may be cleaned with a damp cloth. Do not
allow water to enter the interior of the case or chamber. Do not clean
with organic solvents.
5.2 Calibration
After prolonged use, the controller and/or thermocouple may require recalibration. This
is important for processes that require accurate temperature readings or for those that
use the product close to its maximum temperature. A quick check using an independent
thermocouple and temperature indicator should be made from time to time to
determine whether full calibration is required. Carbolite Gero can supply these items.
Depending on the controller fitted, the controller instructions may contain calibration
instructions.
5.3 After-Sales Service
Carbolite Gero Service has a team of Service Engineers who can offer repair, calibration
and preventive maintenance of furnace and oven products both at the Carbolite Gero
factory and at customers’ premises throughout the world. A telephone call or email
often enables a fault to be diagnosed and the necessary parts to be despatched.
In all correspondence please quote the serial number and model type given on the
rating label of the product. The serial number and model type are also given on the
back of this manual when supplied with the product.
Carbolite Gero Service and Carbolite Gero contact information can be found on the back
page of this manual.
5.4 Recommended Spare Parts and Spare Parts Kit
Carbolite Gero can supply individual spare parts or a kit of the items most likely to be
required. Ordering a kit in advance can save time in the event of a breakdown.
Each kit consists of one thermocouple, one solid state relay and one heating element.
When ordering spare parts please quote the model details as requested above.
14

6.0 Repairs and Replacements
6.1 Safety Warning - Disconnection from Power Supply
Immediately switch the product off in the event of unforeseen
circumstances (e.g. large amount of smoke). Allow the product to return
to room temperature before inspection.
Always ensure that the product is disconnected from the electrical supply
before repair work is carried out.
Caution: Double pole/neutral fusing may be used in this product.
6.2 Safety Warning - Refractory Fibre Insulation
Insulation made from High Temperature Insulation Wool
Refractory Ceramic Fibre, better known as (Alumina silicate
wool - ASW).
This product contains alumino silicate wool products in its thermal insulation. These
materials may be in the form of blanket or felt, formed board or shapes, slab or loose
fill wool.
Typical use does not result in any significant level of airborne dust from these materials,
but much higher levels may be encountered during maintenance or repair.
Whilst there is no evidence of any long term health hazards, it is strongly recommended
that safety precautions are taken whenever the materials are handled.
Exposure to fibre dust may cause respiratory disease.
When handling the material, always use approved respiratory protection
equipment (RPE-eg. FFP3), eye protection, gloves and long sleeved clothing.
Avoid breaking up waste material. Dispose of waste in sealed containers.
After handling, rinse exposed skin with water before washing gently with
soap (not detergent). Wash work clothing separately.
Before commencing any major repairs it is recommended to make reference to the
European Association representing the High Temperature Insulation Wool industry
(www.ecfia.eu).
Further information can be provided on request. Alternatively, Carbolite Gero Service
can quote for any repairs to be carried out either on site or at the Carbolite Gero
factory.
6.3 Temperature Controller Replacement
Refer to the controller instructions for more information on how to replace the
temperature controller.
15
6.0 Repairs and Replacements

6.0 Repairs and Replacements
6.4 Solid-State Relay Replacement
Disconnect the product from the power supply and remove the
appropriate cover as given above.
Make a note of the wire connections to the solid state relay and disconnect them.
Remove the solid state relay from the base panel or aluminium plate.
Replace and reconnect the solid state relay ensuring that the bottom of it has good
thermal contact with the base panel or aluminium plate.
Replace the access panel.
6.5 Thermocouple Replacement
The coverings and guards which must be removed to gain access to the thermocouple
depend on the model, its orientation (horizontal or vertical), and possibly other options
and fittings.
It will usually be necessary to separate the product from its base or stand. On horizontal
models one outer end-cap will need to be removed and on vertical models the terminal
cover. Within some models the thermocouple lies inside the product body; the body
must be removed from the control base and the end-cap and insulation ring removed
from one end.
thermocouple leg colour
positive (type N) pink
negative white
Disconnect the thermocouple from its terminal block. Withdraw the thermocouple from
its sheath and remove any broken bits of thermocouple.
Bend the new thermocouple carefully to match the shape of the original (working from
the terminal end). Should the length differ from that of the original this will usually not
be important provided that the thermocouple tip is within a tube diameter's distance
from the product centre.
Insert the new thermocouple into position, restoring any removed porcelain spacers and
ensuring correct polarity. Re-assemble the product.
6.6 Fuse Replacement
Fuses are marked on the wiring diagram with type codes, e.g. F1, F2. For more
information on fuses refer to section 9.0.
Depending on model and voltage, the different fuse types may or may not be fitted.
If any fuse has failed, it is advisable for an electrician to check the internal circuits.
Replace any failed fuses with the correct type. For safety reasons do not fit larger
capacity fuses without first consulting Carbolite Gero.
16

The fuses are located at the cable entry point. Remove the back panel or control box
back panel to gain access to the fuses.
17
6.0 Repairs and Replacements

6.0 Repairs and Replacements
6.7 Element Replacement
The coverings and guards which must be removed to enable replacement of the wound
tube element depend on the furnace model, its orientation (horizontal or vertical), and
other options and fittings. The general procedure is:
Disconnect the product from the electrical supply.
Remove all outer guards, meshes and terminal covers from the product's body. For a
horizontally mounted product remove the product body from its base; to reach the bolts
or screws which fix the body to the base, remove the back panel from the base.
Disconnect all electrical leads from the terminal blocks on the product case. Note the
colours and positions of the connecting leads to enable correct reassembly. Take care
not to crack porcelain terminal blocks - use two spanners where appropriate.
Remove the thermocouple.
Lay the furnace body horizontally with the split in the cylindrical case uppermost. In the
case of the CTF models undo the self-tapping screws which hold the terminal strip to the
case join. The case will spring open slightly. Remove the ceramic board disc from one
end.
Use a sharp knife to cut right through the insulation down to the wire-wound tube
element along the whole length of the body, but do not cut either of the ceramic board
end discs. The knife cut must be in line with the element lead wires. Slide the element
gently out through the end of the product body.
Check the cylindrical case and clean out as appropriate.
Remove any insulation sleeving from the tails of the old element and fit to the
replacement element.
Slide in the new element(s). Close up the product again, refitting the terminal strip
(where applicable) and the end-caps. Any cut made in the insulation should close up
completely: if the insulation appears loose or damaged in any way, please contact the
Carbolite Gero service division.
Reverse the rest of the disassembly process. Take care to make all connections to the
correct terminals. Do not over tighten the connectors in porcelain terminal blocks.
Let the product heat up at its maximum rate to 900 °C without interruption and then
soak for 1 hour. Fumes may be emitted: this should be done in conditions of good
ventilation.
Check that the product is controlling properly to rule out the possibility that the element
failed because of a fault in the control system.
If you have any problems with this procedure, please contact the Carbolite Gero service
division.
18

7.0 Fault Analysis
A. Furnace Does Not Heat Up
1. The HEAT
light is ON
The heating element
has failed
Check also that the SSR is working
correctly
2. The HEAT
light is OFF
The controller shows a
very high temperature
or code such as S.br
The thermocouple has broken or has
a wiring fault
The controller shows a
low temperature
The door switch(es) (if fitted) may
be faulty or need adjustment
The contactor/relay (if fitted) may
be faulty
The heater switch (if fitted) may be
faulty or need adjustment
The SSR could be failing to switch on
due to internal failure, faulty logic
wiring from the controller, or faulty
controller
There are no lights
glowing on the
controller
Check the supply fuses and any
fuses in the furnace control
compartment
The controller may be faulty or not
receiving a supply due to a faulty
switch or a wiring fault.
19
7.0 Fault Analysis

7.0 Fault Analysis
B. Product Overheats
1.
Product only heats up
when the instrument
switch is ON
The controller
shows a very high
temperature
The controller is faulty
The controller
shows a low
temperature
The thermocouple may be
faulty or may have been
removed out of the heating
chamber
The thermocouple may be
connected the wrong way
around
The controller may be faulty
2.
Product heats up
when the instrument
switch is OFF
The SSR has failed
"ON"
Check for an accidental wiring
fault that could have
overloaded the SSR
20