Unit installation

Use and Maintenance Manual Air-cooled water chillers and Heat Pumps R-PAE/R-PAH/EAH Rev. 1 del 03/09

B) VACUUM AND DEHYDRATATION

To obtain a good level of vacuum, an appropriate pump must be used (1,4 mbar of absolute pressure, 30 l/min.

of water capacity). If the circuit has been open only for short time, by using this pump, only one vacuum

operation is usually enough to reach the absolute pressure

1,4 mbar. If such a vacuum pump is not available or if

the circuit has been open for long time, it is highly recommended to perform the vacuum three times by breaking the

vacuum by means of the refrigerant. This method is also suitable when there is a high quantity of moisture in the

circuit. The vacuum pump must be connected to the charge connections on high and low pressure side of the circuit

Follow this procedure:

Ø Discharge the circuit up to an absolute pressure of 35 mbar, then charge the cooling circuit with

refrigerant gas up to reach a pressure of about 1 bar;

Ø Repeat again the operation as described above reaching an absolute pressure of 35 mbar;

Ø Repeat the above operation for the third time reaching the minimum absolute pressure as possible.

This operation allows to remove up to 99% of the polluting substances.

C) REFRIGERANT CHARGE

Follow this procedure:

Connect the refrigerant gas cylinder to the male charge connection 1/4” SAE placed on the liquid line,

letting some gas go out to remove the air in the connection pipe;

Turn the cylinder upside down and charge the liquid up to reach 75% of the total charge;

Now connect to the charge connection on the suction line and, keeping the cylinder upright, complete

the charge till the temperature of the liquid pipe before the filter is lower than 7-8°C for the chiller (4°C

for the heat pump) compared to the temperature shown on the refrigerant manometer for the discharge

pipe.