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Liebert HPM --- A/W/F/D/H

2.1.7 --- Constant K/L

Refrigeration circuit

All models are provided with a single refrigeration circuit.

The compressor (1) pumps the hot gas eous refrigerant into

an outdoor air---cooled condenser (2). The liquefied refriger-

ant arrives to a liquid receiver (3) that ensures a constant and

even refrigerant flow to the thermostatic expansion valve (4)

and then arrives to the eva porator (5). H ere the refrigerant,

thanks to the heat --- exchanged with the room air moved by

the fan (6) --- evaporates and returns to the compressor (1);

from this, the refrigerant begins a new refrigeration cycle. To

maintain the correct refrigerant discharge pressure, the

speed of th e m otor f an (8) i s con trolled (on---of f or propor-

tional mode).

When the cooling capacity of the room unit is higher than the

room load and the room temperature tends to decrease, the

hot gas valve (11) o pens and the hot gas coil (10) heats the

treated air, maintaining the room at the requested restricted

temperature conditions.

Shut---off valves are provided as standard to assist wit h

routine maintenance.

The compressor (1) has abuilt---in non---returnvalve toavoid

return of liquid ref rigerant from the conden ser in summer-

time, thus protecting the compressor from undesired refri-

gerant slugging during the start up. A second non---return

valve (7) is recommende d to avoid --- in wintertime --- refri-

gerant migration from the liquid pipes and the receiver (3) to

the cond en ser (2), th at sh ould b e resp on sib le of low pres-

sure intervention at the start---up of compressor.

For safety reason, a relief valve (9) is installed on the liquid

receiver (3); this valve is equipped with flanged connections

so that the refrigerant may be discharged to the outside.

SxxKA

MxxKA

Units

SxxKW

MxxKW

Units

Co o ling Wat er

Vertiv Liebert HPM User Manual

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