VERDER CARBOLITE GERO GHC 12/750 Manual

Installation, Operation and Maintenance Instructions
1200°C Tube Furnace (3-zone) - GHC Model: 750mm
No Controller
GHC 12/750 + No Controller
MEN-GHC120750-16_NOCTRL (18-06-2019)

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 5
2.1 Unpacking and Handling 5
2.2 Siting and Setting Up 5
2.3 Work Tubes and Fittings 7
2.4 Electrical Connections 9
2.5 Reconfiguring and Adjusting for Voltage 12
3.0 Temperature Controller 13
4.0 Operation 14
4.1 Operating Cycle 14
4.2 Control Method 14
4.3 3-Zone Control Methods 14
A. Back-to-Back Thermocouples 15
B. Retransmission of Setpoint 15
C. Independent Control 16
4.4 General Operating Advice 16
4.5 Operator Safety 16
4.6 Tube Life 17
4.7 Pressure 17
4.8 Gas Tightness 18
4.9 Running at Low Temperatures 18
5.0 Maintenance 19
5.1 General Maintenance 19
5.2 Maintenance Schedule 19
5.2.1 Cleaning 21
5.3 Calibration 21
5.4 After-Sales Service 21
5.5 Recommended Spare Parts and Spare Parts Kit 21
6.0 Repairs and Replacements 22
6.1 Safety Warning - Disconnection from Power Supply 22
2

6.2 Safety Warning - Refractory Fibre Insulation 22
6.3 Temperature Controller Replacement 22
6.4 Solid-state Relay Replacement 23
6.5 Thermocouple Replacement 23
6.6 Element Replacement 24
6.7 Fuse Replacement 25
7.0 Fault Analysis 26
A. Furnace Does Not Heat Up 26
B. Product Overheats 27
8.0 Wiring Diagrams 28
8.1 WC-13-31 28
8.2 WC-U3-31 29
8.3 WC-U4-31 30
8.4 Higher Voltages 31
8.5 Three-Zone Models 31
8.6 Control by Broadcast Comms (control method B) 31
9.0 Fuses and Power Settings 33
9.1 Fuses 33
9.2 Power Settings 34
10.0 Specifications 35
10.1 Environment 35
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.
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

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.
Work tubes:
It is recommended that the work tube has either insulation plugs or
radiation shields fitted to minimise heat loss from both ends of the work
tube. If the work tube has open ends, a significant amount of energy
could be radiated from the ends of the work tube. Adjacent surfaces
should always be made from a non-flammable material.
Ensure that the ends of the work tube are positioned at least 500 mm
away from any adjacent surface so that any energy radiated cannot heat
an adjacent surface to a dangerous temperature.
5
2.0 Installation

2.0 Installation
Ensure that the product is placed in such a way that it can be quickly switched off or
disconnected from the electrical supply.
This horizontal tube product is supplied with the controls in an integral base (or, to
order, with the base control panel blanked off and the controls in a separate box). A
horizontal tube support kit.
All G-range tube furnaces have “modular” heating elements in which resistance wire is
partially embedded in vacuum formed light-weight refractory fibre. The modules are
150 mm long. In all standard models the two end elements (one at each end) are rated
at 1170 W maximum, while the other (centre) elements are rated at 780 W.
All models are supplied with a pair of “tube adaptors”, which can be made to suit any
work tube size up to 170 mm outside diameter. Spare or replacement adaptors can be
ordered.
The horizontal models generally require no special setting up. Observe the above
paragraph on siting. See section 2.3 for work tube and end adaptor considerations.
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 Work Tubes and Fittings
Tubes of various diameters and
lengths may be fitted.
Type C: minimum length for the
product.
Type D: 400 mm longer than C, to
allow for the fitting of end seals.
A pair of removable 'end adaptors' form part of the end insulation. These may be blank
(no hole) or may have a hole to suit a work tube, depending on the customer order.
Additional adaptors may be ordered to suit different work tube sizes. Check that the
end adaptors are correct for the tube: if not, seek advice from Carbolite Gero. Small
alterations to the hole in the adaptors may be made with a file, but first read the
section on ceramic fibre safety 6.2. To insert a work tube it is often convenient to use a
long pole (such as a broom handle) to guide it into the far end of the product.
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.
Horizontal use: 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. A horizontal tube support kit can be
supplied for this purpose.
If a metal work tube is being used in the product, ensure that it is earthed. See the
"Safety Warning" under "Operator Safety".
7
2.0 Installation

2.0 Installation
Fig 1 - Insulating Plug
(standard length tube) Key
A Tube
B Insulating Plug
C Stem
Fig 2 - Insulating Plug
(long work tube)
8

Key
A Clamp
B Seal plate
C 'O' Ring seal
D Seal sleeve
E Clamp seal
F End plate
Key
A Clamp
B End plate
CClamp seal (between Seal
sleeve and Clamp
D Seal sleeve
ESeal plate & 'O' Ring seal
(underneath clamp)
F Tube
Fig 3 'Twin Clamp' End Seal
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 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 star or delta.
9
2.0 Installation

2.0 Installation
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. The product's electrical access panel should be temporarily
removed, and connections made to the internal terminals.
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).
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:
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)
10

DO NOT connect a product ordered for three phase use to a single
phase supply or to the wrong type of three phase supply.
11
2.0 Installation

2.0 Installation
2.5 Reconfiguring and Adjusting for Voltage
The standard single-phase models can operate over the voltage range 200 - 240 V. The
2-phase models can operate over the range 380/220 V to 415/240 V. The 3-phase
models can operate over the range 380/220 V to 415/240 V.
The product is wired according to the original order and conversion from 1-phase to 2-
phase or 1-phase to 3-phase is not possible. To check for voltage setting within the
appropriate range, or to change to another setting, follow the instructions in section 9.0.
Special Voltages
The products can be specially made to suit certain special voltages, such as 440/254 or
480/277.
Due to unbalanced phases, the furnaces cannot be made to suit 3-phase without neutral
of 380 V or above.
Products made for special voltages are generally not convertible between configurations
and voltages.
12

3.0 Temperature Controller
If this product is fitted with a temperature controller, instructions are provided
separately.
13
3.0 Temperature Controller

4.0 Operation
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.
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 Control Method
Set the three temperature controllers to the desired setpoints. The setting and
operation of the end zone controllers depends on the 3-zone control options selected
when the product was ordered. These options are described in the 3-zone control
methods section.
4.3 3-Zone Control Methods
There are three different control options (A, B & C).
(A) Back to back thermocouples
(B) Retransmission of Setpoint
(C) Independent control
The models listed in this manual are designed to achieve an extended uniform
temperature zone, through use of three control zones, rather than achieving different
temperatures in each zone.
For A & B, the control zones are linked so that they all follow the centre zone controller
in a master-slave approach
14

Note:
lOption A is NOT applicable when using the CC-T1 controller
lOption B is NOT applicable when using the Eurotherm 2132 End Zone Controller
A. Back-to-Back Thermocouples
This is the most commonly supplied option. The centre zone of the tube furnace is
controlled directly by the centre zone temperature controller. The two end zone
thermocouples are wired in opposition to the centre zone reference thermocouple. If
the temperatures of the centre and end zones are the same then 0°C will be displayed
on the end zone controllers. If the end zone temperatures are either higher or lower
than the centre zone, the end zone controller will display the difference in temperature
(higher = positive value, lower = negative value).
It is best practice to set the setpoint of the two end zone controllers to zero.
Alternatively, a small temperature difference (offset) can be created by setting a non-
zero value, for example to compensate for heat losses at the end or where using a gas
flow. However, the sum of the centre zone controller setpoint and the end zone
controller offset MUST NOT exceed the furnace maximum temperature.
To alter the setpoint with the display showing the Home screen, press Down
or Up once to display the setpoint and then press again or hold down to
adjust it. The display returns to the measured temperature when no key is
pressed for a short period of time.
Sometimes a furnace using this type of control does not cool down because the end
zones lose heat first and therefore the end zone controllers try to compensate for this
by switching on the end zone elements, preventing the furnace from cooling.
B. Retransmission of Setpoint
Three independent thermocouples are connected to three controllers. The three
controllers are linked together and the centre zone controller communicates the desired
setpoint to the end zone controllers. If the centre zone controller is set to a setpoint or
is running a program, the end zone controllers will automatically follow.
For products with the CC-T1 controller, please refer to the separate CC-T1 controller
manual for details on enabling and disabling setpoint retransmission.
For other products, additional communication modules are fitted in the controllers. The
communication between the controllers of the Eurotherm 3000 series is known as
Broadcast communications. It is possible to switch off the linked control and allow the
controllers to work independently. In the level 2 menu of the end zone controllers (see
controller operating instruction), scroll to L-r. Where the end zone controller is a 3216
use the up down buttons and select NO. Where the end zone controller is a 3508
use the up down buttons to select SP1, (SP1 = Local, and SP2 = Remote). There
is no need to alter the centre zone controller.
15
4.0 Operation

4.0 Operation
It is possible to set an offset (local trim) between the centre and end zone controllers.
This can be either a positive or negative difference from the centre zone temperature.
Once entered, this offset will always be added to, or subtracted from, the retransmitted
setpoint temperature.
For products with the CC-T1 controller, please refer to the separate CC-T1 controller
manual for details on how to set an offset trim.
To make this adjustment on other controllers, enter thelevel 2 menu of the end zone
controllers (see controller operating instruction), scroll to LOC.T (local trim) and use the
up down buttons to enter the desired positive or negative value. This will then be
added to, or subtract from, the end zone set temperature. There is no need to alter the
centre zone controller.
C. Independent Control
The three controllers are completely independent. Note that it is not possible to
maintain very different temperatures in the three zones because of heat transfer
between the zones. The models listed in this manual are designed to achieve an
extended uniform temperature zone by the use of three control zones rather than
achieving different temperatures in each zone.
4.4 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.
4.5 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.
4.6 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).
Key
A Tube
B Crucible
Fig 4 - Avoidance of thermal contact
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.
4.7 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.
17
4.0 Operation

4.0 Operation
4.8 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.
4.9 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 the Power Settings section of this
manual for default power limits. If the product fails to reach the desired temperature,
refer to the Temperature Controller and Fault Analysis sections.
18

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
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
Safety Switch Function
(split models only)
Set a safe temperature above ambient,
and open the furnace to see if the heater
light goes out
Safety Switch Function
(split models only) Electrical measurement
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
Operational Check Check that all functions are working nor-
mally
Operational Check Thorough inspection and report incor-
porating a test of all functions
Work Tube Position Visually check that the tube is central to
the heated zone (horizontally / vertically)
End Plugs / Radiation Shields Visual check for damage or wear, and cor-
rect positioning
19
5.0 Maintenance

5.0 Maintenance
Seals (if fitted) Check all seals and O-rings and clamps
Performance
Element Circuit Electrical measurement
Power Consumption Measure the current drawn on each
phase / circuit
Cooling Fans (if fitted) Check whether the cooling fans are work-
ing
20