icetro ISI-271THS, User Manual

Page: 69 / 85

69
Service for Refrigerant Lines
3. Vacuuming and recharging (R-404A)
1) Install the vacuum pump on the system. Connect the charging hoses on the charging
nipples of both high-pressure and low-pressure ends.
The vaccum level and vacuum pump may be the same as those for current refrigerants.
However, the rubber hose and gauge manifold to be used for evacuation and refrigerant
charge should be exclusively for POE oils.
2) Turn the vacuum pump on and open the manifold valve.
The oil of the vacuum pump shall not be allowed to leak into the system.
3) Wait until the desired vacuum level is obtained. Vacuuming time may vary depending on
the capacity of the vacuum pump.
4) Open the manifold valves on the high- and low-pressure ends.
5) Remove the manifold hose from the vacuum pump and connect the hose to the
refrigerant service cylinder. Purge air from the hose with the hose kept slightly open.
Use pure refrigerant with no foreign materials.
6) The use of liquid refrigerant is recommended.
Turn the service cylinder upside down on a scale and open the manifold valve on the
high-pressure end.
7) Wait until an adequate amount of refrigerant is injected.
8) If necessary, inject the remaining refrigerant into the low pressure-end. Inject refrigerant
into the low-pressure end while the system operates.
9) Close the manifold valves on the high- and low-pressure ends. Remove the manifold hoses.
10) Reattach the caps on the nipples.
IMPORTANT