Vertiv Liebert CRV - Page 44

4. After completion of leak testing, release the test pressure, (observe local code) and pull an
initial deep vacuum of 500 microns on the system with a suitable pump.
5. After 4hours, check the pressure readings and, if they have not changed, break vacuum with
dry nitrogen. Pull a second and third vacuum to 500 microns or less. Re-check the pressure
after 2hours.
When the 3 checks are complete, proceed to ChargingAir-cooled Systems without
LiebertLee-Temp below.
ChargingAir-cooled Systems without LiebertLee-Temp
Source: DPN002411, Rev. 8
NOTICE
Risk of improper refrigerant charging. Can cause equipment damage.
R-410A is a blended refrigerant and must be introduced and charged from the cylinder only as
a liquid.
When adding liquid refrigerant to an operating system, it may be necessary to add the
refrigerant through the compressor suction service valve. Care must be exercised to avoid
damage to the compressor. We recommend connecting a sight glass between the charging
hose and the compressor suction service valve. This will permit adjustment of the cylinder
hand valve so that liquid can leave the cylinder while allowing vapor to enter the compressor.
NOTICE
Risk of refrigerant overcharge. Can cause equipment damage.
Do not use the sight glass as an indicator when charging Liebert MC condenser systems.
The system must be fully piped and evacuated before it can be charged. See Evacuation and Leak-
testing Air-cooled SystemswithoutLiebertLee-Temp™ on the previous page.
Liebert MC condensers are charge-sensitive and require accurate calculation of the system charge to
avoid overcharging. To avoid overcharge, the following additional guidelines are recommended to ensure
trouble-free operation.
• When charging system in an outdoor ambient below 50°F (10°C), recheck the subcooling
against Table 6.11 on page46 when the ambient is above 60°F (15.6°C)
• The indoor space should be maintained at 70 to 80°F (21 to 26.7°C) return air before final
charge adjustments are made.
• Charging unit at greater than 80°F (26.7°C) return air and low outdoor ambient temperature
may result in the unit being overcharged.
• Charge by subcooling measurement at the indoor unit. See Table 6.11 on page46 for target
subcooling temperatures.
• Pressure and temperature measuring instruments should be capable of measuring to ±10 psig
(68.9kPa) and ± 2°F (1.1°C) for best subcooling measurement.
Vertiv | Liebert CRV Installer/User Guide | 44