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ITS-90 Isothermal Towers Iss.07 – 05/14
To balance this loss a heated collar is included above the cell called an Immersion Compensator; this collar has its own
controller (zone) and follows the main controllers’ temperature.
The main controller and the top zone controller are factory set prior to despatch. The settings can be found on the
melt and freeze graphs that accompany the equipment.
The top zone controller setting should be checked each time the Isotower is used and adjusted if necessary. See the
next section on how to perform this.
Monitoring and Adjusting the Isotower Profile
Switch on and set a temperature 2°C below the cell’s melt/freeze temperature.
Monitor the cell with a stable thermometer. Allow enough time for your Isotower to stabilise.
When the Isotower temperature stabilises, record the temperature then raise the monitor 100mm (4”) and allow the
monitor to stabilise and record the temperature again, ideally the raised temperature should be +0.1°C higher than
the bottom measurement. This takes only 10 minutes and checks for any drift on the Immersion Compensation
Controller.
If the measurements indicate that the top is colder the temperature of the zone controller can be raised by increasing
the setpoint value.
Please note that the relationship between the zone controller temperature and the temperature at the top of the cell
is not linear and an increase of 0.1°C in the zone controllers value will not increase the temperature measurement at
the top of the cell by 0.1°C.
DO NOT set the top temperature more than 2°C above the melt. There is an over-
temperature trip inside the ISOTower preset to 4°C above the melt to protect the heat
siphon. Should you trip the unit you will need to contact Isotech for further instructions.
