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4.4.4.
Refrigerant load
After the drain operation, the system must be loaded with carbon dioxide –CO2 – R744 Purity
≥
99.99%) H2O
≤
10 ppm, O2
≤
10 ppm, N2
≤
50 ppm or higher.
-
R744 refrigerant (CO2) is classified as safety class A1 according to EN 378-1 (non-flammable, non-toxic). ODP
= 0 and GWP = 1. High CO2 concentrations are dangerous. This refrigerant is odourless and colourless.
ATTENTION: The CO2 refrigerant is heavier than air. The use of CO2 detectors and a ventilation
system is recommended if the machine is installed in a machines room or in areas where pockets of
CO2 might form (e.g. underground floors).
ATTENTION: The first phase of refrigerant load, or pre-load, must ONLY take place in the gaseous
phase
For the refrigerant pre-load phase the following are necessary:
x
that the partly-completed machine is electrically powered so that the YVEq.P YVEq.LT compressor
bypass solenoid valves (if present) are energised);
x
that the condensing unit and therefore the compressor and/or the compressors are in the OFF position
from the electronic control keyboard;
x
that the valves HPV and VFL are manually opened by electronic control to guarantee opening of the
entire refrigeration circuit
During refrigerant pre-load it is necessary to insert CO2 in the gaseous state at a pressure value well above
the triple point (5.185 bar(a)) to avoid the formation of dry ice inside the system. A gaseous pre-filling of 10
bars is recommended throughout the circuit
The load points are RS1, RS2, RS3 and RS1.LT and RS2.P (if present).
The reading of the pressure on each section is possible from the main screen of the electronic control.
ATTENTION: Do not power the solenoid valve coils if they are not installed on the valve itself.
The next phase of loading consists of restoring the partly-completed machine, putting the condensing unit
and/or the compressors in ON from electronic control and following the steps provided in the chapter on
starting up.
Loading can then continue in liquid phase on RS3 tap, in vapour phase on RS1, RS1.LT (if present).
The utilities must be activated.
ATTENTION: The utilities must already be configured and programmed correctly for use with CO2.
ATTENTION: Activate the utilities gradually during loading.
ATTENTION: During the loading phase the compressors will be activated and any alarms in the initial
phase may be present.
