Emerson Liebert MC Microchannel Outdoor Condenser 28 - 220kW Manuale Utente
Piping
35
Liebert
®
MC
™
5.9
Liebert MC Condenser Charging, Units without Liebert Lee-Temp
™
Systems
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 13 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 may result in the unit being overcharged.
• Charge by subcooling measurement at the indoor unit. See Table 13 for target subcooling
• Charge by subcooling measurement at the indoor unit. See Table 13 for target subcooling
temperatures.
• Pressure and temperature measuring instruments should be capable of measuring to ±10 psig
(103.4kPa) 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. Refrigerant charging requires unit operation. Refer to the indoor unit’s user manual for details
regarding indoor unit operation and 6.0 - Checklist for Completed Installation for the Liebert
MC condenser operation.
3. Calculate the amount of charge for the system. Refer to the indoor unit user manual, and
condenser and refrigerant line charge data in Tables 10 and 12.
4. Accurately 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 (.37kg).
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
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
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 condenser systems.
Do not use the sight glass as an indicator when charging Liebert MC condenser systems.
5. Turn On the Liebert MC disconnect switch.
6. Turn on the indoor unit disconnect switch. Operate the unit for 30 minutes using the charging
6. Turn on the indoor unit disconnect switch. Operate the unit for 30 minutes using the charging
function of the indoor unit control for each circuit of the system. The charging function is in the
diagnostic section of the Liebert iCOM
®
control (see Liebert 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.
7. Attach pressure and temperature instruments to the liquid line of the indoor unit. Measure the
initial subcooling and continue to add charge until recommended subcooling for the current
outdoor ambient temperature is reached. See Table 13. The outdoor ambient can be read from
the Liebert MC condenser control menu ID F02.