EN
i-ACCURATE i-AX - i-AW - i-AD - i-AT - i-AF
47
VACUUM AND CHARGE
The refrigerant circuits of the water-cooled chillers and air-condi-
tioners are already charged with refrigerant, either R410A or
R410A (check the rating plate on the unit and the compressors
to see which type of refrigerant is used).
The air-cooled air-conditioners (i-AX - i-AD) and the BRE units
that require refrigerant connections to other units are pre-
charged with nitrogen (or dry air) to prevent moisture from
entering the circuit; in this case, the refrigerant charge must be
completed by the installer, following the instructions shown in this
paragraph.
Refrigerant
Type of oil
R410A (POE)
mod. 12-18-20-29
FV50S
mod. 50-70-90-130-150
160SZ
COMMISSIONING PROCEDURE
Arm
the cutout in the auxiliary circuits;
Arm
all the cutouts on the electrical panel;
Power up the air-conditioner electrical panel and close the main
disconnecting switch on the unit (position 'I');
Check
that the control board is powered;
Check
that both the
LEDs relating to the phase sequence relay (RSF) are on; the yel-
low LED indicates power, the green LED indicates that the
sequence of phases is correct.
If the green LED is off, disconnect power supply from the units,
reverse two phases of the power cable and restart the commis-
sioning procedure. (In the units with sump heaters)
After having powered up the air-conditioner, wait at least 12
hours before starting so as to suitably heat the oil in the com-
pressors. During extended shutdown there may be spontaneous
migration of refrigerant to the compressor sump, which at the
start may cause the oil to foam and consequent damage due to
insufficient lubrication.
As a result, do not disconnect power during weekly pauses;
Open the on-off valves in the refrigerant circuits and check that
the air-cooled remote condensers are connected (air-cooled
models); Check that the external radiators are connected and
make sure there is water flow for cooling (water-cooled models);
Check that the sections of corrugated pipe with the function of
drain trap (both inside and outside of the air-conditioner) have
been filled with water during installation.
AT LEAST 12 HOURS AFTER POWER UP:
Start
the air-conditioner using the buttons on the user terminal;
If an alarm is activated
refer to the controller instruction
manual.
Open any valves in the unit or in the system to ensure that all the components are involved in the emptying operation;
Connect a high efficiency vacuum pump to the Schrader fittings or to the 1/4" SAE fittings on the compressor suction and discharge side;
Connect a cylinder of refrigerant to the charge fittings.
Empty the lines, ensuring an absolute pressure of less than 10 Pa (0.07 mm Hg) so as to remove the air and any traces of moisture
Praticare il vuoto nelle linee mantenendo a lungo una pressione inferiore a 10 Pa assoluti (0,07 mm Hg) per evacuare l’aria e le eventuali
tracce di umidità.
The circuit should be emptied slowly and maintained for an extended period, rather than performed too quickly.
Wait a "go up time" of 100 seconds and verify that the pressure does not exceed over 200 Pa absolute.
In general, if there is the chance of significant moisture content in the circuit or for very large systems, the vacuum must be “broken” with
nitrogen dioxide and then repeat the emptying operations as described.
Break the vacuum by pre-charging from the cylinder of refrigerant.
After having started the compressor, complete the charge slowly, until the pressure stabilises in the lines and the gas bubbles disappear
from the flow indicator;
The charge must be checked at the environmental design conditions and with a discharge pressure of around 28 bar (R410A (equal to a
dew point of 48°C and boiling point of 43°C); for units with on-off condenser control, partially close the intake to stop the condenser
fan from repeatedly starting-stopping.
Make sure that the subcooling of the liquid at the thermostatic valve intake is between 3 and 5°C less than the condensing temperature
read on the pressure gauge and that the superheating of the vapour at the evaporator outlet is around 5 °C.
R410A
If a circuit already charged with refrigerant needs to be emptied, the first operation required is the removal of the refrigerant from the cir-
cuit using a special appliance with dry compressor for recovering the refrigerant. If available, also switch on the sump heaters during the
emptying operation.
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