IOM / TELECOOL THN - 0104 - E Page 11
STARTING UP
STARTING UP
PRELIMINARY CHECKS
-
Check that the electrical connections have been made
properly and that all the terminals
are securely tightened
.
This check should also be included in a periodic six-month
inspection.
-
Check that the voltage at the RST terminals is 400 V ±
5% and
make sure
the yellow indicator light of the phase
sequence relay is on. The phase sequence relay is
positioned on the electric control board; if the sequence
is not duly observed, it will not enable the machine to start.
-
Make sure there are no refrigerant leaks that may have
been caused by accidental impacts during transport and/
or installation.
-
Check the power supply to the crankcase heating
elements, where present.
The heating elements must be turned
on at least 12 hours before the unit is
started. They are automatically
activated when the main switch is put
on. Their function is to raise the T of
the oil in the sump and limit the
quantity of refrigerant dissolved in it.
To verify whether the heating elements are working properly,
check the lower part of the compressors: it should be warm or
in any case at a temperature 10 - 15 °C higher than the ambient
temperature.
The diagram above illustrates a specific property of gases
[Charles’ Law], which are more soluble in liquids as the
pressure increases but less soluble as the temperature
increases: if the oil in the sump is held at a constant pressure,
an increase in temperature will significantly reduce the amount
of refrigerant dissolved in it, thus ensuring that the desired
lubricating function is maintained.
Pressure
Oil T
% R407C in oil
