Charging The Liebert Mc ™ With Refrigerant-Basic And Premium Efficiency Control - Emerson Liebert Challenger iCOM 3000 Operation & Maintenance Manual

3.4.7 Charging the Liebert MC
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 a system when the outdoor temperature is below 50°F (10°C), recheck the
subcooling against Table 6 when the ambient is above 60°F (15.6°C).
• The indoor space should be maintained between 70°F and 80°F (21-26.7°C) return air before final
charge adjustments are made.
• Charging a unit when return air temperatures are above 80°F (26.7°C) may result in the unit
being overcharged.
• Charge by subcooling measurement at the indoor unit. See Table 6 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 indoor nameplate for refrigerant type to be used. Unit control configurations differ
depending on refrigerant type.
2. Completing the refrigerant charging requires operating the system for the latter steps. Refer to
the Checklist for Completed Installation in the Liebert Challenger 3000 installation manual,
SL-11962.
3. Calculate the amount of charge for the system. Refer to the Liebert Challenger 3000 installation
manual, SL-11962, and to the condenser and refrigerant line charge data in Tables 4 and 5 in
this document.
4. Accurately weigh in as much of the required system charge as possible before starting the unit.
Do not exceed the calculated charge by more than 0.5 lb (.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. Emerson recommends 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 systems.
5. Turn On the Liebert MC disconnect switch.
6. Turn On the Liebert Challenger 3000 disconnect switch
7. Operate the system for 30 minutes, using the charging function of the Liebert Challenger 3000
control for each circuit of the system.
The charging function is in the diagnostic section of the Liebert iCOM
iCOM user manual, SL-18835). The charging function operates the compressor(s) at full capacity
and energizes the liquid line solenoid valve(s). The reheat and humidifier are disabled. Manual
operation of the indoor fans from the diagnostic menu of the Liebert iCOM is required. A
minimum 20psig (138kPa) must be established and maintained for the compressor to operate.
The charging function can be reset as many times as required to complete unit charging.
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Liebert ® Challenger 3000
™
with Refrigerant—Basic and Premium Efficiency Control
14
Component Operation and Maintenance
control (see the Liebert
®