5.7.2 Liebert MC Condenser Charging with Liebert DSE
™
Receivers
Consult the Liebert DSE manual (SL-18925) for charging Liebert DSE systems. All Liebert DSE require
installation of a Liebert DSE receiver on each condenser circuit, with or without a Liebert EconoPhase
pump module installed. Consult Table 5.6 on page76 for condenser and receiver refrigerant
requirements.
5.7.3 Liebert MC Charging, Premium Efficiency Control, Units without Receivers
Source: DPN002411, Rev. 7
Liebert MC condensers are charge-sensitive and require accurate calculation of the system charge to
avoid overcharging. To avoid overcharge, 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 5.10 on the next page when the ambient temperature is above 60°F (15.6°C)
• The indoor space should be maintained at 70-80°F (21-26.7°C) return air before final charge
adjustments are made.
• Charging a unit at temperatures above 80°F (26.7°C) return air may result in the unit being
overcharged.
• Charge by subcooling measurement at the indoor unit. See Table 5.10 on the next page for
target subcooling temperatures.
• Pressure and temperature measuring instruments should be capable of measuring to ±10 psig
(68.9kPa) and ± 2°F (1.1°C) for best subcooling measurement.
1. Check the nameplate on the indoor unit for refrigerant type to be used. Unit control
configurations differ depending on refrigerant type.
2. Refrigerant charging requires the unit to be in operation. Refer to the indoor unit’s user
manual for the Checklist for Completed Installation.
3. Calculate the amount of charge for the system. Refer to the indoor unit user manual, and
condenser and refrigerant line charge data in the appropriate tables.
4. Weigh in as much of the system charge as possible before starting the unit.
Do not exceed the calculated charge by more than 0.5 lb. (0.23kg).
NOTICE
Risk of improper refrigerant charging. Can cause equipment damage.
Refrigerant R-407C and R-410A are blended refrigerants 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.
Vertiv™ recommends connecting a sight glass between the charging hose and the compressor suction
service valve. This will permit adjusting 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.
Vertiv | Liebert® MC™ Installer/User Guide | 79
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