VERDER Carbolite Gero LHT 4/120 Manual

Installation, Operation and Maintenance Instructions
400°C Laboratory High Temperature Oven - LHT Model: 120
Litres
No Controller
LHT 4/120 + No Controller
MEN-LHT4120-006_NOCTRL (18-10-2021)

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 Electrical Connections 7
3.0 Temperature Controller 9
4.0 Operation 10
4.1 Operating Cycle 10
4.2 Over-Temperature Control (if fitted) 10
4.3 Explosive Vapours 10
4.4 Atmospheres 11
4.5 Operator Safety 11
4.6 Solenoid Valve with Manual Switch (if fitted) 11
4.7 Variable Speed Fan (if fitted) 12
4.8 Exhaust Fan (if fitted) 12
4.9 Stoving and Curing (if fitted) 12
4.9.1 Pre-heater (if fitted) 12
5.0 Maintenance 13
5.1 General Maintenance 13
5.2 Maintenance Schedule 13
5.2.1 Cleaning 15
5.3 Calibration 15
5.4 After-Sales Service 15
5.5 Recommended Spare Parts and Spare Parts Kit 15
5.6 Power Adjustment 15
6.0 Repairs and Replacements 17
6.1 Safety Warning - Disconnection from Power Supply 17
6.2 Safety Warning - Refractory Fibre Insulation 17
6.3 Panel Removal 18
6.3.1 Side Panel 18
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6.3.2 Internal Element Cover 18
6.4 Temperature Controller Replacement 19
6.5 Solid-State Relay Replacement 19
6.6 Thermocouple Replacement 19
6.7 Element Replacement 19
6.8 Fuse Replacement 20
7.0 Fault Analysis 21
A. Oven Does Not Heat Up 21
B. Oven Overheats 21
8.0 Wiring Diagrams 22
8.1 WV-11-01 22
8.2 WS-10-01 - Isolating for 208 V version only 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
1.1 Switches and Lights
Instrument switch: when the instrument switch is operated the
temperature control circuit is energised.
Solenoid valve (if fitted): see section 4.6 for full details
Variable speed fan (if fitted): see section 4.7 for full details
Exhaust fan (if fitted): see section 4.8 for full details
Stoving and curing (if fitted): see section 4.9 for full details
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.
4

DANGER – Read any warning printed next to this symbol.
Caution – Double Pole/Neutral Fusing
5

2.0 Installation
2.1 Unpacking and Handling
When unpacking or moving the product, always lift by its base; do not use the door or
any other projecting cover or component to support the equipment when moving it. Use
a fork lift or pallet truck to move the product; position the product on a level surface
and use an adequate number of personnel to safely move the product into position.
Carefully remove any packing material from inside and around the product before use.
Avoid damaging the surrounding insulation when removing packing materials.
Locate the shelves as required.
Some models may be lifted by fitting lifting bolts to captive threads which are fitted in
the top of the case, whilst others may have welded on lifting eyes.
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
Note: This LGP oven is supplied with a floor stand that elevates it approximately 500
mm off the ground.
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 Electrical Connections
Connection by a qualified electrician is recommended.
This product requires a single-phase A.C. supply with earth (ground), which may be
Live to Neutral non-reversible (polarised), Live to Neutral reversible (non-polarised), or
Live to Live.
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.
7

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:
8

3.0 Temperature Controller
If this product is fitted with a temperature controller, instructions are provided
separately.
9

4.0 Operation
4.1 Operating Cycle
The product is fitted with an instrument switch. The switch cuts off power to the
controllers and elements. The circulation fan will operate when the instrument switch is
on. An optional door switch may be fitted. If so, ensure that the door is closed to
operate the fans and heating elements.
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.
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 the product off, turn off the instrument switch. If the product is to be left
unattended, isolate the electricity supply.
DO NOT switch off if the temperature is above 100 °C - damage could be caused to the
fan and motor. Adjust the controller to allow the temperature to fall.
4.2 Over-Temperature Control (if fitted)
The over-temperature controller should typically be set at 15 °C above the main
controller. If an over-temperature condition occurs, check the main controller is
functioning correctly.
An over-temperature condition cuts off power to the heating elements. A light in the
over-temperature controller flashes. To reset this, refer to the over-temperature control
section of this manual.
4.3 Explosive Vapours
Unless your product includes the stoving and curing option, this
model is not suitable for drying or heat treatment applications where
vapours are released that are combustible or which can form
explosive mixtures with air. Carbolite Gero manufactures other
products suitable for these applications.
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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.
4.5 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.
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.
4.6 Solenoid Valve with Manual Switch (if fitted)
If ordered the solenoid valve is operated using the panel mounted
switch. When the switch is in the 'ON' position the solenoid valve
will allow gas to
flow. Ensure the installation and use of the product does not create a hazardous
atmosphere. The workspace must have sufficient ventilation.
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4.7 Variable Speed Fan (if fitted)
If fitted, the variable speed control is fitted in the air circulation fan circuit. A
panel mounted rotary dial is used to control the speed.
Please note that there is a minimum setting at which the fan motor starts up when the
product is switched on. It is recommended that the speed of the fan is not set below
50%, as there would be very little air flow around the chamber and also risk
overheating the fan motor.
4.8 Exhaust Fan (if fitted)
To operate the exhaust fan use the fan switch on the control panel; this is
only functional when the instrument switch is on.
The level of air exhaust can be controlled by adjusting the slider under the
exhaust box.
When the exhaust fan is turned on, there may be a drop in internal temperature before
the product recovers to the setpoint value.
The airflow should be adjusted to the minimum required by the process to reduce the
amount of energy wasted in heating air.
4.9 Stoving and Curing (if fitted)
The stoving and curing option adds an explosion relief panel and a powered
exhaust fan. With this option the exhaust fan operates continuously when the
product is switched on.
A pressure switch detects that there is sufficient air flow through the chamber. If the
pressure switch does not detect sufficient air flow, a fault light illuminates and heating
is disabled.
At least 610 mm free space must be left around the explosion relief panel to allow this
to break out if there is a rapid build up of pressure inside the chamber.
Please note that if the stoving and curing option is fitted, there may be an increase in
the power rating of the product. See the product rating label located on the side panel
of the product for correct power rating.
4.9.1 Pre-heater (if fitted)
Products with the stoving and curing option may also be fitted with a pre-heater that
pre-heats the incoming air to the same temperature set on the main controller.
The temperature of the pre-heater is controlled by the main controller, but measured
by a separate thermocouple.
12

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 tem-
perature and check for an over-tem-
perature alarm as detailed in this
manual
Over-Temperature Safety Circuit
(if fitted) Electrical measurement
Door Seal Visual inspection - check for splits or
fraying
Door Seal Replacement
Air Vent 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
Operational Check Check that all functions are working
normally
Operational Check Thorough inspection and report incor-
porating a test of all functions
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Performance
Cooling Fans (if fitted) Check whether the cooling fans are
working
Circulating Fan
(if fitted) Visual check to see if it is running
Circulating Fan
(if fitted)
Check bearings and replace if neces-
sary
Element Circuit Electrical measurement
Power Consumption Measure the current drawn on each
phase / circuit
Shelves Visual check for fit and damage
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5.2.1 Cleaning
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.
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.
5.3 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.
5.4 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.
5.5 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 a fan and motor assembly, a thermocouple, a solid state relay, an
element (or set of elements) and a door seal. Individual spare parts are also available.
When ordering spare parts please quote the model details as requested above.
5.6 Power Adjustment
The control system incorporates electronic power limiting, but for the model listed in
this manual the power limit is set to 100%. The power limit parameter OP.Hi may be
accessible to the operator, but should not generally be altered.
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In some cases the supply voltage may be outside the range 220-240 V or the 3-phase
equivalent, the power limit parameter may be set to a value other than 100%. Do not
increase the value to 100%, see section 9.0 for details of power limit settings.
16

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.
17

6.3 Panel Removal
Disconnect the product from the electrical supply.
6.3.1 Side Panel
The side panel is located on the right-hand side of the product. To gain access to the
products electrical components:
1. Remove all screws holding the panel in place. The bottom of the panel is con-
structed in such a way that it will hinge downwards and allow access to electrical
components without the need to remove the panel entirely
2. Ensuring that the bottom edge of the panel remains in contact with the main cas-
ing, carefully lower the panel downwards to expose the products electrical com-
ponents
Note: Make a note of all connections before disconnecting any wiring.
6.3.2 Internal Element Cover
To gain access to the heating element, thermocouple and fan:
1. Open the oven door. The internal element cover is situated on the right-hand side
of the oven chamber
2. Remove any shelves fitted inside the chamber
3. Remove all screws holding the internal element cover in place
4. Gently lift the panel away from the main oven chamber lining and remove it from
the product
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6.4 Temperature Controller Replacement
Refer to the controller instructions for more information on how to replace the
temperature controller.
6.5 Solid-State Relay Replacement
Disconnect the product from the power supply and remove the
appropriate cover as given above.
1. Make a note of the wire connections to the solid state relay, then disconnect them.
2. Remove the solid state relay from the base panel or aluminium plate.
3. Replace and reconnect the solid state relay ensuring that the bottom of it has
good thermal contact with the base panel or aluminium plate.
4. Replace the access panel.
6.6 Thermocouple Replacement
Disconnect the product from the power supply. Remove the appropriate
panel to gain access to the thermocouple connections. Make a note of the
thermocouple connections.
Thermocouple cable colour codings are:
Thermocouple Leg Colour
positive (type K) green
negative white
1. Disconnect the thermocouple to be replaced from its terminal block and withdraw
it.
2. Re-assemble the new thermocouple, observing the colour coding.
3. Refit the element access panel.
6.7 Element Replacement
lRemove the side panel and the internal element cover (see section 6.3). The ele-
ment terminals are located in the side compartment.
lDisconnect the wires from the heating element terminals.
lRemove any starlock washers - these may need to be cut with wire cutters.
lRemove any clips holding the element inside the chamber and withdraw the ele-
ment.
lReverse the procedure when fitting the new heating element.
lTo find out whether the heating element failure was caused by a fault in the control
circuit, operate the product at a low temperature and check that it is functioning cor-
rectly.
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6.8 Fuse Replacement
Fuses are accessed by removal of the appropriate panel, as described in the 'Panel
Removal' section. Depending on the model, supply fuses and control circuit fuses may
be mounted in their own holders, or may be on a circuit board that contains an EMC
filter. The fuses are marked with their ratings.
Take care not to disconnect the wires leading from the EMC filter without first recording
their positions: they must be reconnected to the correct terminals.
Note: The main fuses for PF 30 models are located in an external fuse holder
positioned next to the IEC socket for the power supply cable.
20