Setup mode
Chapter 4
OPERATION MANUAL
V1.2.0en/12.05.15//14.06
Liability for errors and misprints excluded.
Unistat® T300 Series
63
>Expansion vessel cap<
[22]. The
>Isolating sleeve<
[27]
must
be mounted in
externally open
systems in the
>Expansion vessel<
[18]. Consequently, the
>Expansion vessel<
[18] is closed off
from the externally open application and you can also place the temperature control unit below
the externally open application.
Close all valves, in case of standard devices the
>Venting valve expansion vessel<
[21] by turning
them clockwise (turn 90° right as far as it will go).
Add suitable thermal fluid to the bath. The thermal fluid flows over the return line into the tem-
perature control unit and over the flow line to the bath. This forces the air inside the tempera-
ture control unit outside.
Go to the “Categories Menu”.
Tap on the category “Temperature Control”.
Tap on the category “Start/Stop”.
Tap on the Dialog entry “Start air-purge”.
Confirm your choice by tapping on “OK”.
Using the number keypad that appears, enter the time interval for venting. The default is 0.5
minutes.
Confirm your entry by tapping on “OK”. Venting will start.
The volume expansion of the thermal fluid varies as a function of the working temperature range
in which you wish to work. When working at the “lowest” working temperature, a
“Min” mark
in
the bath vessel (top edge of the back flow + about 1 cm safety margin) must not be undercut, and
when working at the “highest” working temperature, a
“Max” mark
in the bath vessel must not be
exceeded. In the event of overfilling a table-top model and prior to starting, drain thermal fluid
into a suitable container via
>Drain<
[8] by additionally opening the
>Drain valve<
[4] (by turning it
counterclockwise (turn it 90° to the left as far as it will go)) or
by skimming off bath liquid from the
bath. In case of free-standing models drain thermal fluid via
>Drain<
[8] and by opening the
>Drain
valve thermofluid<
[3]
(by turning it counterclockwise (turn 90° to the left as far as it will go)). In
case of too little thermal fluid, the pump draws air instead of thermal fluid. This “Dry run” of the
pump is detected by the sensors and electronics and a safety shutdown occurs. Therefore, ensure
there is sufficient thermal fluid.
Stop venting. To do this, go to the category “Temperature Control”.
Tap on the category “Start/Stop”.
Tap on the dialog entry “Stop air-purge”.
Confirm your choice by tapping on “OK”. Venting is stopped and the pump continues to run for
approx. 30 seconds. Wait until the pump stops.
4.4.2.2
Degassing externally open applications
Hot or cold thermal fluid and surfaces
BURNS TO LIMBS
Avoid direct contact with the thermal fluids or the surfaces.
Wear your personnel protective equipment (e.g. temperature-resistant safety gloves, safety
goggles, safety footwear).
When changing from low-boiling thermal fluid (low-boiling component) to higher boiling thermal
fluid, remains of the low-boiling component may remain in the temperature control unit. Depend-
ing on the working temperature, the low-boiling component begins to boil, gas bubbles form and
cause the pump pressure to momentarily collapse. This may cause a safety shutdown. The gas
bubbles reach the bath opening and can escape.
If ice crystals form on the evaporator coil, water has accumulated in the thermal fluid. If this is the
case, degas to avoid damage to the temperature control unit.
Thermal fluids are hygroscopic (water-attracting) to a greater or lesser degree. This effect increases
as the working temperature decreases. The off-gassing mode below, which must be
permanently
monitored
, also helps you remove any water residues from the temperature control circuit.
PROCEDURE
Follow venting with the degassing operation. Prerequisite: You have filled the temperature con-
trol unit in accordance with the instructions on page 62 in section
»Filling and venting externally
and/or cleaned it as per page 82 in section
»Cleaning the thermal fluid cir-
.
