VERDER Carbolite Gero HTMA 6/28 Manual

Installation, Operation and Maintenance Instructions
600°C Modified Atmosphere Oven - HTMA Model: 28 Litres
No Controller
HTMA 6/28 + No Controller
MEN-HTMA6028-05_NOCTRL (01-09-2022)

Contents
This manual is for guidance on the use of the Carbolite Gero product specified on the
front cover. This manual should be read thoroughly before unpacking and using the
furnace or oven. The model details and serial number are shown on the back of this
manual. Use the product for the purpose for which it is intended.
1.0 Symbols and Warnings 4
1.1 Switches and Lights 4
1.2 General Warnings 4
2.0 Installation 5
2.1 Unpacking and Handling 5
2.2 Siting and Setting Up 5
2.3 Flat Pack Stand (optional) 7
2.3.1 Parts Supplied 7
2.3.2 Flat Pack Stand Assembly 8
2.4 Electrical Connections 9
3.0 Temperature Controller 11
4.0 Operation 12
4.1 Operating Cycle 12
4.2 Over-Temperature Control (if fitted) 12
4.3 Explosive Vapours 12
4.4 Variable Speed Fan (if fitted) 13
4.5 Exhaust Fan (if fitted) 13
4.6 Stoving and Curing (if fitted) 13
4.6.1 Pre-heater (if fitted) 13
4.7 HTMA - Manual Gas Control (if fitted) 14
4.8 HTMA - Automatic Gas Control (if fitted) 14
4.9 Oxygen Sensor (if fitted) 14
4.9.1 Recommended Gas Flow Rates 14
4.10 Door Switch (if fitted) 14
5.0 Maintenance 15
5.1 General Maintenance 15
5.2 Maintenance Schedule 15
5.2.1 Cleaning 17
5.3 Calibration 17
5.4 After-Sales Service 17
5.5 Recommended Spare Parts and Spare Parts Kit 17
5.6 Power Adjustment 17
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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 Control Panel Removal 19
6.4 Temperature Controller Replacement 20
6.5 Solid-State Relay Replacement 20
6.6 Thermocouple Replacement 20
6.7 Element Replacement 21
6.8 Fuse Replacement 21
7.0 Fault Analysis 22
A. Oven Does Not Heat Up 22
B. Oven Overheats 22
8.0 Wiring Diagrams 23
8.1 WV-11-01 23
8.2 WS-10-01 - Isolating for 208 V version only 24
9.0 Fuses and Power Settings 25
9.1 Fuses 25
9.2 Power Settings 25
10.0 Specifications 26
10.1 Environment 26
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1.0 Symbols and Warnings
1.1 Switches and Lights
Instrument switch: when the instrument switch is operated the
temperature control circuit is energised.
Door lock indicator: When this lamp is illuminated, the door is locked
and cannot be opened.
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 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
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.
5

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.
6

2.3 Flat Pack Stand (optional)
The flat pack stand is available in a range of sizes depending on the dimensions of the
product for which it has been ordered. Subsequently, the number of fixings may vary
between the different sizes of stand.
2.3.1 Parts Supplied
Stand Top (x1) Stand Leg (x2)
Stand Cross Brace (x2) M10 Bolt
M10 Washer M10 Locking Nut
7

2.3.2 Flat Pack Stand Assembly
8

2.4 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.
9

Check the product rating label before connection. The supply voltage should agree with
the voltage on the label and the supply capacity should be sufficient for the current on
the label.
The supply should be fused at the next size equal to, or higher than the current on the
label. This manual contains a table of the most common fuse ratings.
When the mains cable is factory fitted, internal fuses are also fitted. It is essential that
the operator ensures that the product is correctly fused.
Products with a factory fitted supply cable are designed to be wired directly to an
isolator or fitted with a line plug.
Products without a factory fitted supply cable require a permanent connection to a
fused and isolated supply. The product's electrical access panel should be temporarily
removed, and connections made to the internal terminals.
When connecting the product to the power supply, the plug or isolating switch should
be accessible, easy to remove, and within reach of the operator.
The supply MUST incorporate an earth (ground).
Supply Terminal Label Cable Colour
Supply Types
Live - Neutral Reversible or Live-
Live
1-phase L1 Brown to live
to either power
conductor
(For USA 200-240V,
connect L1)
N / L2 Blue to neutral
to the other power
conductor
(For USA 200-240V,
connect L2)
PE Green/ Yellow to earth
(ground) to earth (ground)
Electrical Connection Details:
10

3.0 Temperature Controller
If this product is fitted with a temperature controller, instructions are provided
separately.
11

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 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.
4.5 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.
4.6 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.
4.6.1 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.
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4.7 HTMA - Manual Gas Control (if fitted)
The two gas solenoid valves are controlled by a three position switch located on the
front of the product.
When the switch is in the Purge position the gas flows through the Purge flow meter.
This is a high flow used to purge the chamber at the beginning of the cycle.
When the switch is in the Process position the gas flows through the Process flow
meter. This is a low flow used when the process is operating.
When the switch is in the off position then no gas flows.
4.8 HTMA - Automatic Gas Control (if fitted)
Eurotherm 3508 Controller/Nanodac / CC-T1 Option required
The two gas solenoid valves are controlled by program segment output relays in the
main program controller.
Program segment relay 1 controls the Purge flow. This is a high flow used to purge the
chamber at the beginning of the cycle. The purge time is set as a dwell period at
ambient temperature.
Program segment relay 2 controls the Process flow. This is a low flow and should be on
during the heat and cool down stages of the cycle.
The program segment relay outputs are set to on or off when the controller is being
programmed. See controller handbook for details.
4.9 Oxygen Sensor (if fitted)
The gas outlet is fitted with a probe that measures the quantity of oxygen in the
exhaust gas flow. This figure is displayed on the main temperature controller. If a data
logger is fitted, the measured oxygen level is recorded alongside the setpoint and
temperature data throughout the process, and is displayed as a percentage value.
4.9.1 Recommended Gas Flow Rates
Please see sections 4.7 and 4.8 for information on manual and automatic gas flow
rates.
Gas flow rates are configurable to suit individual process requirements.
This product is capable of achieving oxygen levels down to 50 ppm (parts per million)
within the chamber. To achieve this level, it is recommended that a purge flow rate is
set at 20 litres per minute for 25 minutes, followed by a process flow rate of 8 litres
per minute.
4.10 Door Switch (if fitted)
If ordered, the door switch will isolate the heating elements and circulation fan. The
door switch is operated when the door is opened causing the heating elements and air
circulation fan to be switched off.
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5.0 Maintenance
5.1 General Maintenance
Preventive rather than reactive maintenance is recommended. The type and frequency
depends on the product use; the following are recommended.
5.2 Maintenance Schedule
CUSTOMER
QUALIFIED PERSONNEL
DANGER! ELECTRIC SHOCK. Risk of fatal injury. Only electrically
qualified personnel should attempt these maintenance procedures.
Maintenance
Procedure Method
Frequency
Daily Weekly Monthly Bi-
Annually Annually
Safety
Safety Switch Function
With the gas supply on but the oven
at ambient, open the door and make
sure the gas ceases to flow
Safety Switch Function Electrical measurement
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
Electrical Safety (external) Visual check of external cables and
plugs
Electrical Safety (internal) Physically check all connections and
cleaning of the power plate area
Non-Return Valve Check that the small ball in the non-
return valve is free to move
Function
Temperature Calibration
Tested using certified equipment, fre-
quency dependent on the standard
required
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Operational Check Check that all functions are working
normally
Operational Check Thorough inspection and report incor-
porating a test of all functions
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.
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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 Control Panel Removal
Disconnect the product from the electrical supply.
19

Control panel - HT models. Remove the screws holding the panel. Note that the panel
remains connected by wiring. Do not disconnect any wiring without first making a
careful note of all the connections.
Internal element cover. Open the door, remove any screws holding the panel and any
clips holding thermocouples in position and remove the cover.
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
Undo any clips holding the thermocouple. Remove the air guide from the oven
chamber. Disconnect the thermocouple from its terminal block. Unscrew the
compression fitting inside the chamber and pull the thermocouple into the chamber.
Cut through the thermocouple behind the olive and remove the two parts. Loosely
assemble compression fitting with a new ferrule. Feed in new thermocouple through
from the back. Tighten the compression fitting. Refit the air guide. Bend the
thermocouple to match the shape of the previous part and refit any clips.
Refit the element access panel.
Compression fittings are only fitted to moisture extraction and stoving and curing
products. If fitted, ferrules need replacing.
20