Isotech HYDRA 798 Operating instructions

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Hydra 798 Iss.10 –04/18
STIRRED LIQUID BATH
MODEL HYDRA 798
User Maintenance Manual/Handbook
Isothermal Technology Limited, Pine Grove, Southport, PR9 9AG, England
Tel: [phone] Fax: [phone] Internet: www.isotech.co.uk E-mail: [email protected]
The company is always willing to give technical advice and assistance where appropriate. Equally, because of the programme of
continual development and improvement we reserve the right to amend or alter characteristics and design without prior notice.
This publication is for information only.

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Hydra 798 Iss.10 –04/18
CONTENTS
GUARANTEE.......................................................................................................................................................................... 3
ELECTRICAL SAFETY.................................................................................................................................................... 5
Environmental Ratings..................................................................................................................................................... 5
HEALTH AND SAFETY INSTRUCTIONS..................................................................................................................... 6
ON ARRIVAL.................................................................................................................................................................. 7
SPECIFICATION .................................................................................................................................................................... 8
FRONT PANEL CONTROLS................................................................................................................................................. 9
REAR PANEL ........................................................................................................................................................................ 10
IMPORTANT READ THIS NOW! ............................................................................................................................... 11
CHILLERS ......................................................................................................................................................................... 11
Chiller function - Medium ............................................................................................................................................. 11
Chiller function - Low ....................................................................................................................................................... 12
Chiller gases and quantities ........................................................................................................................................... 12
SETTING UP..................................................................................................................................................................... 12
USING THE CONTROLLER ................................................................................................................................................ 13
FRONT PANEL LAYOUT ................................................................................................................................................ 13
The Temperature Controller........................................................................................................................................ 13
Altering the Setpoint ..................................................................................................................................................... 13
ADVANCED CONTROLLER FEATURES........................................................................................................................ 13
Setpoint Ramp Rate....................................................................................................................................................... 13
Instrument Address....................................................................................................................................................... 14
MONITORING THE CONTROLLER STATUS ............................................................................................................... 14
Units.............................................................................................................................................................................. 14
OVER TEMPERATURE CONTROLLER (H MODEL ONLY) .......................................................................................... 15
OVER AND UNDER TEMPERATURE CONTROLLER (M & L MODELS) ..................................................................... 15
OVER TEMPERATURE CONDITION ............................................................................................................................. 15
UNITS ................................................................................................................................................................................... 17
DIAGNOSTIC ALARMS........................................................................................................................................................ 17
CONTROLLER ERROR MESSAGES................................................................................................................................. 17
OPERATION AND INITIAL TESTING ................................................................................................................................ 18
MOTOR NOTE .................................................................................................................................................................... 18
CHOICE OF LIQUIDS.......................................................................................................................................................... 19
LIQUID LEVEL.................................................................................................................................................................. 19
CHANGING LIQUIDS...................................................................................................................................................... 20
USING THE COOLING COIL ............................................................................................................................................. 21
CLEANING AND MAINTAINING THE BATH ................................................................................................................... 22
USING THE PC INTERFACE ............................................................................................................................................... 23
Connections ...................................................................................................................................................................... 23
Using the Interface ............................................................................................................................................................ 23
CAL NOTEPAD.................................................................................................................................................................... 24
Minimum System Requirements ....................................................................................................................................... 24
Development .................................................................................................................................................................... 24
Licence .............................................................................................................................................................................. 24
Installing Cal NotePad ....................................................................................................................................................... 25
Starting Cal NotePad ........................................................................................................................................................ 25
Protocol ............................................................................................................................................................................ 25
ACCESSORIES ...................................................................................................................................................................... 26

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Hydra 798 Iss.10 –04/18
GUARANTEE
ⓒIsothermal Technology Limited
This instrument has been manufactured to exacting standards and is guaranteed for twelve months against
electrical break-down or mechanical failure caused through defective material or workmanship, provided the
failure is not the result of misuse.
In the event of failure covered by this guarantee, the instrument must be returned, carriage paid, to the
supplier for examination and will be replaced or repaired at our option.
FRAGILE CERAMIC AND/OR GLASS PARTS ARE NOT COVERED BY THIS GUARANTEE INTERFERENCE
WITH OR FAILURE TO PROPERLY MAINTAIN THIS INSTRUMENT MAY INVALIDATE THIS GUARANTEE
The company is always willing to give technical advice and assistance where appropriate. Equally, because of
the programme of continual development and improvement we reserve the right to amend or alter
characteristics and design without prior notice. This publication is for information only.
This handbook contains information that has been reproduced with the kind permission of Eurotherm. Such
data is subject to the following notice.
Isothermal Technology Limited
Pine Grove, Southport, Merseyside, PR9 9AG, England
Telephone: [phone]/544611 / Fax: [phone]
Email: [email protected]o.uk / Website: www.isotech.co.uk

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Hydra 798 Iss.10 –04/18
CAUTIONARY NOTE
ISOTECH PRODUCTS ARE INTENDED FOR USE BY TECHNICALLY TRAINED AND COMPETENT
PERSONNEL FAMILIAR WITH GOOD MEASUREMENT PRACTICES.
IT IS EXPECTED THAT PERSONNEL USING THIS EQUIPMENT WILL BE COMPETENT WITH THE
MANAGEMENT OF APPARATUS WHICH MAY BE POWERED OR UNDER EXTREMES OF
TEMPERATURE, AND ARE ABLE TO APPRECIATE THE HAZARDS WHICH MAY BE ASSOCIATED WITH,
AND THE PRECAUTIONS TO BE TAKEN WITH, SUCH EQUIPMENT.

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Hydra 798 Iss.10 –04/18
EMC INFORMATION
This product meets the requirements of the European Directive on Electromagnetic Compatibility (EMC)
89/336/EEC as amended by EC Directive 92/31/EEC and the European Low Voltage Directive 73/25/EEC,
amended by 93/68/EEC. To ensure emission compliance please ensure that any serial communications
connecting leads are fully screened.
The product meets the susceptibility requirements of EN 50082-1, criterion B.
Symbol Identification
Publication
Description
ISO3864
Caution (refer to handbook)
IEC 417
Caution, Hot Surface
ELECTRICAL SAFETY
This equipment must be correctly earthed.
This equipment is a Class 1 Appliance. A protective earth is used to ensure the conductive parts cannot
become live in the event of a failure of the insulation.
The protective conductor of the flexible mains cable which is coloured green/yellow MUST be connected to a
suitable earth.
The blue conductor should be connected to Neutral and the Brown conductor to Live (Line).
Warning: Internal mains voltage hazard. Do not remove the panels.
There are no user serviceable parts inside. Contact your nearest Isotech agent for repair.
Voltage transients on the supply must not exceed 2.5kV.
Conductive pollution e.g. Carbon dust, must be excluded from the apparatus. EN61010 pollution degrees 2
Environmental Ratings
Operating Temperature 5-50°C
Relative Humidity 5-95%, non condensing

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Hydra 798 Iss.10 –04/18
HEALTH AND SAFETY INSTRUCTIONS
1. Read this entire handbook before use.
2. Wear appropriate protective clothing.
3. Operators of this equipment should be adequately trained in the handling of hot and cold items and
liquids.
4. Do not use the apparatus for jobs other than those for which it was designed, i.e. the calibration of
thermometers.
5. Do not handle the apparatus when it is hot or cold, unless wearing the appropriate protective clothing
and having the necessary training.
6. Do not drill, modify or otherwise change the shape of the apparatus.
7. Do not dismantle the apparatus without disconnecting it from the supply and leaving time for it to
reach ambient temperatures.
8. Do not use the apparatus outside its recommended temperature range.
9. The apparatus is protected by an over temperature circuit, ensure correct settings at all time.

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ON ARRIVAL
You should have the following parts,
1. Main Bath Assembly
2. One overflow and one drain pipe
3. Lid
4. This handbook
5. PC Interface Lead (yellow)
Optional accessories are available and will only be present if specified on your order.
In the unlikely event of any items arriving damaged please retain the packing materials (which may need to be
inspected later) and then contact your supplier.

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Hydra 798 Iss.10 –04/18
SPECIFICATION
798H
Ambient to 300°C**
798EHT
Ambient to 300°C
798M
-40 to 125°C
798L
-80 to 125°C
Volume
150mm diameter, 300mm deep (5 litres)
Dimensions
400mm Wide
615mm Deep
800mm Height
Absolute Stability
±0.01°C
Best Comparison Accuracy
±0.002°C
Communications
RS422
Uniformity 125°C (oil)
Vertical 0.002°C
Horizontal 0.001 to 0.0025°C
Uniformity 200°C (oil)
Vertical 0.005°C
Horizontal 0.001 to 0.0035°C
Safety
Compliant to CE Regulations
Power
798EHT
800W
110V 50/60Hz
230V 50/60Hz
798H
800W
110V 50/60Hz
230V 50/60Hz
798M
1.5 KW
110V 50/60Hz
230V 50/60Hz
798L
2.5 KW
110V 50/60Hz
230V 50/60Hz
**
The temperature range of the Hydra 798H was increased from 200°C to 300°C from 2016.

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FRONT PANEL CONTROLS
A OVER/UNDER-TEMPERATURE CONTROLLER (SAFETY)
B TEMPERATURE CONTROLLER
C HEATER ENABLED
D ON / OFF SWITCH
E FLOW CONTROL

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REAR PANEL

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IMPORTANT READ THIS NOW!
CHILLERS
The M and L models include an internal mechanical refrigeration unit. During transit the internal oil can be displaced.
On arrival the equipment should be left for 24 hours in an upright position to allow any displaced oil to settle.
Chiller function - Medium
The chiller is designed to automatically enable at any temperature below 40°C. The chiller will run all the time and
the temperature control is balanced by the heater. The chiller will have unwanted cooling power at the higher
temperatures, such as temperatures above -10°C; it can cause unwanted instability in the liquid temperature. To
prevent this, the Hydra has an automatic cooling reduction facility built in. This is in the form of an internal by-pass
valve that will reduce the running pressure of the refrigeration system.
The by-pass valve will automatically enable at temperatures above -10°C until the chiller is automatically switched off
at 40°C. Because of the time taken to cool down from higher temperatures with the by-pass enabled and reduced
cooling, the by-pass valve only actually opens when the actual temperature is within ±3 °C of the set point. This
allows the full cooling at all other times.
The functions of the chiller can be identified by the display of the controller on the front panel. Refer to the
controller section on page 15 for details.
The diagram below gives a graphical account of the Hydra medium chiller function
(1) Chiller enabled.
(2) Full cooling, by-pass valve off
(3) By-pass valve enabled
(4) Band of temperature where by-pass
valve is active.

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Chiller function - Low
The Hydra Low has a cascade refrigeration system. This allows the bath to reach temperatures in excess of -80°C.
The chiller is fully automated and requires no user intervention.
Because of the complex nature of this refrigeration system, it is recommended that in the event of service, you
contact Isotech for advice as it is generally beyond the scope of standard refrigeration systems.
Chiller gases and quantities
Hydra Medium
Gas used R404A
Quantity ~ 550grams
Hydra Low
Gas used
High stage R404A
Quantity ~350 grams
Low stage R23
Quantity ~100grams
SETTING UP
The whole manual should be carefully read before using the bath, and then set the bath up as follows.
Connect the drain pipe to the drain tap and the overflow pipe to the rear panel ports. Place a suitable container under
the overflow pipe. Ensure the tap is shut, i.e. lever at 90°. If the equalising block is to be used it should be placed in
position now.
Fill the bath with suitable liquid, water is probably best for initial testing. Fill the bath until the level is 45mm below the
top lid of the bath.
ALWAYS ISOLATE THE BATH FROM THE ELECTRICAL SUPPLY WHEN CHANGING LIQUIDS

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Hydra 798 Iss.10 –04/18
USING THE CONTROLLER
FRONT PANEL LAYOUT
The Temperature Controller
The controller has a dual display, the upper display indicates the nominal liquid temperature, and the lower display
indicates the desired temperature or setpoint.
Altering the Setpoint
To change the setpoint of the controller simply use the UP and DOWN keys to raise and lower the setpoint to the
required value. The lower display changes to indicate the new setpoint.
ADVANCED CONTROLLER FEATURES
Setpoint Ramp Rate
By default the bath is configured to heat (and cool) as quickly as possible. There may be some calibration applications
where it is advantageous to limit the heating (or cooling rate).
An example might be when testing bimetallic thermostats, by forcing the bath to heat at a controlled rate it is easier
to determine the temperature at which the thermostat changes state.
The bath can have its heating rate limited with the Setpoint Ramp Rate feature. This feature is accessed from the
Scroll key. Depress the key until the display shows,
OFF
SP.RAT
The upper display will show the current value and is adjustable from OFF to 999.9. The units are °C/min and are
adjustable via the UP/DOWN keys.
When the SP.RAT is active the lower setpoint display will now automatically update with the current value, known as
the working setpoint. The setpoint can be seen by pressing either the UP and DOWN key.
The Setpoint ramp rate operates when the bath is heating and cooling.

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Instrument Address
The controller has a configurable "address" which is used for PC communications. Each instrument has an address;
this allows several instruments to be connected in parallel on the same communications bus. The default value is 1 for
the controller and 2 for the over/under temperature controller. This address would only need to be changed if more
than one piece of equipment is connected to the same PC port.
To check the Address value press the scroll key until the lower display indicates,
ADDR
The upper display will show the current value that can be modified with the UP and DOWN keys.
MONITORING THE CONTROLLER STATUS
A row of beacons indicate the controllers status as follows,
Output 1 (op1)
Heater –shows when the heater is active, seen to pulse to display heater output
REM
This beacon indicates activity on the PC interface
Output 2 (op2)
(M Only)
Full cooling –When illuminated shows full cooling and the by-pass valve is closed.
When not illuminated, indicates the by-pass valve is open and reduced cooling is
enabled
Output 4 (op4)
Indicates the chiller is enabled and working
Units
The units can be changed from °C. Press the scroll key until the lower displays shows
UNITS
Use the UP and DOWN keys to select the desired display unit. Continue to press the scroll key to access the
following options
Pb
Ti
Td
These controls allow the user more level of control over the bath performance and should only be adjusted if the user
has a full understanding of PID control systems.

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OVER TEMPERATURE CONTROLLER (H MODEL ONLY)
This device is an important safety feature. It has its own temperature sensor and will isolate the heater if the
temperature exceeds the set temperature. It should be set slightly higher, perhaps 10 –20°C higher than the working
temperature or to the maximum safe temperature of the fluid in use. Whichever is the lowest value. IT MUST BE SET
IN THIS WAY TO ENSURE SAFE USE OF THE BATH. Suitably set it will allow for protection against component
failure and also operator error when setting the controller, either from the front panel or remotely from a computer.
The heat enabled beacon will be lit when the over-temperature controller is in safe mode.
Set the desired value on the lower display using the UP and DOWN keys.
OVER AND UNDER TEMPERATURE CONTROLLER (M & L MODELS)
The M model has a low temperature trip in addition to a high temperature trip. The low temperature trip will turn
the chiller off and can be used to safe guard water triple point cells or the liquid in the bath from freezing.
The high trip will isolate the heater if the bath temperature exceeds the set value.
Set the High Trip value to a suitable value, perhaps 10 –20°C higher than the operating temperature but lower than
the flash point of the liquid. Set this value into the A1 Hi Parameter.
Set the Low Trip value to a suitable value, perhaps the minimum safe operating temperature for the calibration into
the A2 Lo Parameter.
To access these parameters press the scroll key until they appear on the lower display and modify the value shown on
the top display with the up and down keys.
OVER TEMPERATURE CONDITION
In the unlikely event of an over temperature or under temperature condition the Hydra will go to Alarm condition.
Depending which of the alarms has been triggered the unit will either disable the heater or the cooler accordingly.
The Temperature Policeman controller will identify which alarm has been triggered by the scrolling lower display.
The message will read as follows:
OVERTEMPERATURE CONDITION –ATTENTION REQUIRED
UNDERTEMPERATURE CONDITION –ATTENTION REQUIRED
The respective illuminated beacon will also switch off.

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To reset the heater or cooler, the condition must be removed, that is the temperature must be restored to the
correct value by either waiting for the temperature to normalise, or by resetting the controller to a more suitable
value. The controller will need to be reset manually, even if the controller is switched off, it will still power up again
in the alarm condition until reset.
To reset the controller, ensure the temperature for both over and under temperature is safe then press both the
PAGE button and the SCROLL button simultaneously. The scrolling warning display will disappear and the illuminated
beacon light up.

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UNITS
Momentary pressing the Scroll key will show the controller units °C or °F.
DIAGNOSTIC ALARMS
These indicate that a fault exists in either the controller or the sensor.
CONTROLLER ERROR MESSAGES
The instruments include powerful diagnostics and in the unlikely event of an internal failure, or a sensor error, one of
the following error messages may be displayed.
Display shows
What it means
What to do about it
EE.Er
Electrically Erasable Memory Error:
The value of an operator or configuration
parameter has been corrupted
Contact Isotech
S.br
Sensor Break:
Input sensor is unreliable or the input
signal is out of range.
Contact Isotech
Check rear panel to ensure
connection of both control and over-
temperature sensors
HW.Er
Hardware error :
Indication that a module is of the wrong
type, missing or faulty
Contact Isotech
LLLL
Out of Display range, low reading
Contact Isotech
HHHH
Out of Display range, high reading
Contact Isotech
Err1
Error 1: ROM self-test fail
Consult Isotech
Err2
Error 2: RAM self-test fail
Consult Isotech
Err3
Error 3: Watchdog fail
Consult Isotech
Err4
Error 4: Keyboard failure
Stuck button, or a button was pressed
during power up.
Switch the power off and then on
without touching any of the controller
buttons.
Err5
Error 5: Input circuit failure
Consult Isotech
Pwr.F
Power failure . The line voltage is too low
Check that the supply to the
controller is within the rated limits

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OPERATION AND INITIAL TESTING
Set the bath up as described in the earlier "Setting Up Section". For convenience it is suggested that a newly received
bath should be tested at 50°C with water as the operating liquid.
Connect the bath to the supply and switch on.
1. Set the over temperature controller to a suitable value, see earlier.
2. Set the set point of the temperature controller to the desired value 50.0°C.
3. The bath should now reach and control at the target set point.
4. Select the correct stir speed using the dial on the left side of the control panel, turning the dial clockwise will
increase the stir speed and anti clockwise will reduce it.
The bath may now be used for calibration.
MOTOR NOTE
This bath has a variable speed motor control installed. This allows the user to select the optimum stir speed for the
liquid and temperature choice.
The motor is a brushed DC drive motor and uses internal carbon brushes, available from Isotech.
Motor speed can be adjusted via the dial on the control panel, rotate the dial clockwise to increase the stir speed and
counterclockwise to reduce the stir speed.

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CHOICE OF LIQUIDS
The choice of liquid is important. If it is too viscous at the operating temperature then the bath may not perform
correctly. Other criteria also need to be met, such as safety, operating range and fume emission for example. Isotech
is able to supply a number of fluids for various temperature ranges, refer to Volume 1 and 2 of the Solutions
Catalogues.
Unfortunately, there is not one fluid which can be used over the whole operating range of the bath.
Beware of oils that are claimed to work from below ambient to over 100°C. Whilst we do not supply or recommend
such liquids, others do. It is our experience that such oils are hygroscopic. Then at temperatures around 100°C this
moisture boils and can lead to the oil spilling from the top of the bath. Even without the boiling risk, the oil is soon
spoilt by the ingress of moisture and the oil has to be replaced regularly, which can be an expensive task. It will be
seen that when changing fluids from say water to oil that it is important that ALL the water has been removed before
adding the oil.
As oils approach their upper operating limit fumes become significant and fume extraction becomes essential.
Isothermal Technology manufactures a Fluidised Alumina Bath, the 875 Bath which overcomes the limitations of oils
and may be used to 700°C without fuming problems.
Below ambient we use a mixture of Ethanol and water or pure Ethanol. It needs to be used very carefully by those
suitably trained and aware of the dangers if handled inappropriately. As local safety requirements vary not only from
country to country but also from organisation to organisation the safety aspects of these fluids should be determined
with the user’s safety officer.
LIQUID LEVEL
All liquids expand as they are heated and contract when they cool.
The bath has been designed to allow for varying liquid volumes and also features an overflow system which prevents
the liquid from spilling from the top of the bath.
The optimum liquid level with the motor off at the operating temperature is for the liquid to be approximately 25mm
from the top of the calibration tube.
Ensure at all time that the liquid level is kept at the correct level and that the liquid is circulating around the bath. If
the level falls excessively the flow will stop with a consequence of large temperature gradients. If a liquid is being
used close to its flash point a hazard could then occur.

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CHANGING LIQUIDS
If possible it is best to plan so that liquids do not need to be frequently changed. This may be achieved by liquid
choice, determining convenient calibration points or having more than one bath - each with a different liquid to cover
the routine calibration range.
To change the liquid,
1. Disconnect from the supply.
2. Ensure the liquid is at a safe handling temperature. Then open the drain tap.
3. Drain the liquid into clean containers of adequate capacity, properly labelled for future use.
4. Clean the bath. Detergent and absorbent paper will assist. If the bath has been used with oil it can be helpful
to re fill with water and detergent and to allow the mixture to circulate before draining again.
5. Close the tap.