VERDER CARBOLITE GERO EHA 12/300B Manual

Installation, Operation and Maintenance Instructions
1200°C E-Range Tube Furnaces - EHA Model: 300mm
No Controller
EHA 12/300B + No Controller
MEN-EHA12300B-005_NOCTRL (30-01-2018)

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
1.3 Warning Labels 5
1.3.1 - Control Box layout and warning labels. 6
1.3.2 - Back of control box showing mains lead socket 6
2.0 Installation 7
2.1 Unpacking and Handling 7
2.2 Siting 7
2.3 Setting Up 7
2.3.1 Figure - Furnace model mounted on a control box 8
2.3.2 Figure - Exploded view showing how to fit the work tube in the furnace 8
2.3.3 Figure - Tube support 9
2.3.4 Figure - Tube support assembly 10
2.3.5 Figure - Tube support and end seal assembly 10
2.3.6 Figure - Tube support and end seal assembly 11
2.3.7 Figure - Cross-section view showing standard length work tube insu-
lation plug fitted 12
2.3.8 Figure - Cross-section view showing extended work tube insulation
plug fitted 12
2.3.9 Figure - Cross-section view showing an extended length work tube with
a radiation shield fitted 12
2.4 Electrical Connections 12
3.0 Temperature Controller 14
4.0 Operation 15
4.1 Operating Cycle 15
4.2 Safe Operation of the Furnace 15
4.3 General Operating Advice 16
4.4 Operator Safety 16
4.5 Tube Life 17
4.6 Pressure 17
4.7 Gas Tightness 17
5.0 Maintenance 18
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5.1 General Maintenance 18
5.1.1 Cleaning 18
5.2 Calibration 18
5.3 After-Sales Service 18
5.4 Recommended Spare Parts and Spare Parts Kit 18
6.0 Repairs and Replacements 19
6.1 Safety Warning - Disconnection from Power Supply 19
6.2 Safety Warning - Refractory Fibre Insulation 19
6.3 Temperature Controller Replacement 19
6.4 Solid-state Relay Replacement 20
6.5 Thermocouple Replacement 20
6.6 Element Replacement 20
6.7 Fuse Replacement 21
7.0 Fault Analysis 22
A. Furnace Does Not Heat Up 22
B. Product Overheats 23
8.0 Wiring Diagrams 24
8.1 WA-11-30 24
8.2 WA-11-31 25
8.3 WA-12-30 26
8.4 WA-12-31 27
9.0 Fuses and Power Settings 28
9.1 Fuses 28
9.2 Power Settings 29
10.0 Specifications 30
10.1 Environment 30
Furnace drying out process 31
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
1.3 Warning Labels
On the front control panel there are 2 warning labels as shown in Figure 1.3.1; they are
numbered 7 and 8. These warnings must be followed for the safe operation of this
furnace.
7- Warning label - Do not operate without a work tube.
The furnace must not be operated without the correctly sized work tube
and correspond work tube adaptors or it could be possible for an
operator to access electrically live element coils that could cause serious
injury or death.
8- Warning label - Switch off the furnace before loading and
unloading.
The furnace heaters must be switched OFF using the heater switch, item
2 in Figure 1.3.1, when the furnace is being loaded or unloaded. The
work tube can become electrically conductive at high temperatures,
presenting a possible hazard to the operator. If element failure is left
undetected the element could collapse onto the work tube.
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1.0 Symbols and Warnings

1.0 Symbols and Warnings
Index to numbered items in Figure 1.3.1
and 1.3.2
1. Electrical supply switch - switches
electrical power ON and OFF to the
furnace.
2. Heater switch - switches electrical
power ON and OFF to the furnace
heating elements.
3. Heater ON light - indicates that the
furnace heating elements are ener-
gized.
4. Product rating label indicating the
product serial number and electrical
information.
5. Access holes to front panel fixing.
6. Warning label - Disconnect the
mains supply before removing this
cover.
7. Warning label - Do not operate
without a work tube.
8. Warning label - Switch OFF the fur-
nace before loading and unloading.
9. Electrical power lead socket.
10. Back panel fixing screws.
1.3.1 - Control Box layout and warn-
ing labels.
1.3.2 - Back of control box showing
mains lead socket
6

2.0 Installation
If the product has been transported or stored in humid conditions it
must be dried out completely before operating the furnace. Contact
Carbolite Gero Service for instructions.
2.1 Unpacking and Handling
When unpacking or moving the product, always lift it by its base or both ends of the
main body. Never lift it by the end insulation or by a work tube. It may take 2 or 3
people to lift the furnace, depending on the size and configuration.
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
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.
If the product is to be used in a process which could liberate hazardous gases, then it
should be installed together with a suitable fume extraction system.
Ensure that the product is placed in such a way that it can be quickly switched off or
disconnected from the electrical supply.
2.3 Setting Up
The horizontal models must have work tubes fitted before being used. The diameter of
the work tube is a customer order option and therefore varies between tube furnaces.
Note: If a metal work tube is being used in the furnace, ensure that it is
earthed. See 4.4.
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.
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2.0 Installation

2.0 Installation
Fitting the standard length work tube to furnace
Tools required: 4 mm Allen key
Fitting work tube is as follows with reference to Figure 2.3.2. Please note that standard
length work tubes are also referred to as tubes suitable for working in air. They are 150
mm longer than the heated length of the furnace (see the Specifications table at the
back of this manual). Read section 6.2 before fitting the work tube.
2.3.1 Figure - Furnace model mounted
on a control box
2.3.2 Figure - Exploded view showing
how to fit the work tube in the furnace
Index to numbered items in Figure 2.3.2
1. Tube furnace body
2. Work tube (diameter customer option)
3. Work tube adaptor (size dependent on work tube diameter)
4. Work tube adaptor fixing bracket
5. Work tube end stop (size dependent on work tube diameter)
6. Fixing screws M6 x 15
7. Washer M6
8. Tube furnace end guard
lRemove the work tube end guard (8) then remove the work tube adaptor fixing
bracket (4) that holds in place the work tube end stop (5) and the end adaptor (3)
from one side only. Note that if a different work tube with a different outer diameter
is being fitted it will be necessary to fit new correctly sized work tube adaptors (3) in
which case both end guards and work tube adaptor fixing brackets (4) will need
removing.
lSlide the work tube into the furnace through the work tube adaptor (3) until it
reaches the opposite work tube end stop (5). Note that the work might be a tight fit
when it is new and may need to be twisted backwards and forwards slightly as it
slides in. For long work tubes it may be necessary to use a long wooden pole such as
a broom handle to support and line up the work tube as it pushed through. It may
also take 2 people to perform this operation.
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lReassemble the work tube end stop (5), work tube adaptor bracket (4) and tube end
guard (8).
Fitting the extended work tube in the furnace
Tools required 4 mm Allen key.
Fitting of the work tube is as follows with reference to Figure 2.3.2 2.2.
lBefore the extended work tube can be fitted, the work tube end stops for the stand-
ard length work tube (item 5 in figure 2.3.2 ) must be removed from both ends of
the furnace. This is done by removing the furnace end guard (8) and the work tube
adaptor brackets (4) to release the work tube end stop. The guards and brackets
should then be refitted.
lFit the tube support bracket, (15), figure 2.2. Use supplied M6 button head screws
and supplied washers.
lFit the extended work tube guard, (14), figure 2.2. Use supplied M6 button head
screws and supplied washers.
lRe-fit furnace end guard, (13), figure 2.2. Use supplied M6 button head screws and
supplied washers.
lIf supplied fit the optional tube end seal assembly as shown in figure 2.2. refer to
manual MEN-ENDSEALS-01 for detailed fitting instructions.
lFit tube support bracket, (7), figure 2.2. Use supplied M6 button head screws and
supplied washers.
lFinally fit tube support collar, (5) and secure figure tight using (6) until tube is secure
to be used in a vertical arrangement. Fitting arrangement is shown in figure 2.2.
lFigure 2.2 - shows an exploded view of all the required parts.
lFigure 2.2 - shows the assembled parts as they would be used.
2.3.3 Figure - Tube support
9
2.0 Installation

2.0 Installation
2.3.4 Figure - Tube support assembly
2.3.5 Figure - Tube support and end seal assembly
10

2.3.6 Figure - Tube support and end seal assembly
Index to numbered items in figure 2.3.5 - 2.3.12
1. Blank plate
2. Seal
3. Clamp
4. Boss
5. Tube support collar
6. Fluted grip knob
7. Tube support bracket
8. M6 button head screw
9. M6 washer
10. Clamp
11. O Ring
12. Clamp ring
13. Standard end guard
14. Extended work tube guard
15. End adaptor
Fitting the Optional Insulation Plugs and Radiation Shield
For optimum temperature uniformity, insulation plugs or radiation shields should be
placed in the work tube ends as shown below. With a standard work tube, the stem (8)
(see figure 2.3.2) of the insulation plug assembly lines up with the end of the work tube.
If a gas/vacuum end seal is fitted, either horizontally or vertically, the insulation plug
hooks onto the end seal hook; see figure 2.3.8.
Alignment of radiation shields is similar to that of insulation plugs, see below.
If a metal work tube is being used in the furnace, ensure that it is earthed. See the
safety warning in section 4.4.
11
2.0 Installation

2.0 Installation
2.3.7 Figure - Cross-section view show-
ing standard length work tube insulation
plug fitted
2.3.8 Figure - Cross-section view show-
ing extended work tube insulation plug
fitted
2.3.9 Figure - Cross-section view showing an extended length work tube with a radi-
ation shield fitted
2.4 Electrical Connections
Connection by a qualified electrician is recommended.
All furnaces in the range are single-phase and operate over the voltage ranges 100 to
110 volts or 200 - 240 volts. Check the rating label before connection, see "Warning
Labels" for location of rating label. To check that the OP.Hi setting is correct for the
appropriate voltage, or to change to another setting, follow the instructions in section
0.1.
The electrical supply should be fused at the next standard size equal to or higher than
the design current. Where a supply cable is supplied there are internal supply fuses, in
which case customer fusing is preferred but not essential. See section 9.0 for furnace
rating power, current and fusing information.
12

The external connection should be either a permanent connection to a fused isolator
supply or to a socket on a fused isolator supply; the isolating switch must operate on
both conductors. Make sure that the isolator switch is within easy reach of the furnace
operator.
Supply Terminal
Label
UK/ Europe
Cable Colour
USA/
Canada
Common
Cable
Colours
Supply Type
Live -
Neutral
Reversible or
Live - Live
1-phase
L Brown Red or
Black To live to either power conductor
N Blue White To neutral to the other power
conductor
PE Green/ Yellow
Green or
Green/
Yellow
To earth
(ground) to earth (ground)
Terminal Connection Details
13
2.0 Installation

3.0 Temperature Controller
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 controller. The controller
illuminates 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.
Switch on the heater switch, located on the instrument panel. Unless a time switch is
fitted and is switched off, the product will start to heat up. The Heat light(s) glow
steadily at first and then flash as the product approaches the desired temperature or a
program setpoint.
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 Safe Operation of the Furnace
For the safe operation of this furnace the following warnings must be followed:
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4.0 Operation

4.0 Operation
Explosive Materials
The furnace must not be used to heat materials which could explode, or
which could emit gases that could form explosive mixtures. If the safe
heating of a material is dependent on its temperature, only heat these
type of materials if the furnace has the optional over-temperature
protection device fitted. Ensure that the over-temperature device is
calibrated and set to an over-temperature safety limit that is sufficiently
large as to avoid any hazards. If in doubt, seek expert advice before
proceeding. Customers are responsible for carrying out their own risk
assessments on the heating of materials.
Do not operate without a work tube. The furnace must not be
operated without the correctly sized work tube and correspond work
tube adaptor. Otherwise, an operator can access electrically live
element coils that could cause serious injury of death.
Switch off the furnace before loading and unloading. The furnace
elements must be switched off using the heater switch, item 2 in
"Warning Labels", when the furnace is being loaded or unloaded. The
work tube can become electrically conductive at high temperatures. If
an element has failed and collapsed onto the work tube, the work tube
will become live causing serious injury or death.
4.3 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.
Clean up any spillages in the insulation, as these can increase the rate of degradation of
the insulation material.
4.4 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).
16

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.
4.5 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.
4.6 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.
4.7 Gas Tightness
Work tubes of IAP material are impervious. Sillimanite may look similar but is porous.
Ensure that the correct tube material is in use before connecting and using gases other
than inert gases, such as nitrogen.
17
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 and one solid state relay.
When ordering spare parts please quote the model details i.e. model type and serial
number as stated on the rating label.
18

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.
19
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
For vertical models it may be necessary to dismount the furnace from its stand and
remove the terminal cover.
Disconnect the product from the power supply. Remove terminal cover to gain
access to the thermocouple connections. Make a note of the thermocouple
connections.
Thermocouple cable colour codings are:
thermocouple leg colour
positive (type N) pink
negative white
Disconnect the thermocouple from its terminal block.
Carefully withdraw the thermocouple from the product 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 is usually not
important provided that the thermocouple tip is within a work tube diameter's distance
from the furnace centre.
Insert the new thermocouple into position, restoring any removed porcelain spacers and
ensuring correct polarity.
Re-assemble the furnace.
6.6 Element Replacement
Individual elements are not available for this model of product, if an element fails then a
complete element assembly is required. For details and fitting instructions contact
Carbolite Gero Service, see the back page of this manual for contact information.
20