Charging DA250 Air Cooled Systems (Liebert® MCV440 with Receivers)
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 improper operation. Can cause compressor failure.
Operating the unit with the EEV closed can cause compressor failure. The reheat and humidifier are disabled. A
minimum of 20 psig (138 kPa) must be established and maintained for the compressor to operate. The
charging function can be reset as many times as required to complete
To charge the system:
1.
Check the nameplate on the indoor unit for refrigerant type to be used. Unit control configurations differ
depending on refrigerant type.
2.
The unit must be operating during charging, refer to
Checklist for Completed Installation
3.
Calculate the amount of charge for the system. See
Refrigerant Charge Requirements for Air Cooled Systems
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 (0.37 kg).
5.
Close the MVC heat rejection skid disconnect switch.
•
We recommend charging the unit with the return air setpoint between 75°F and 85°F (24°C and 29°C).
•
The return air temperature to the unit being charged must be stable and must be maintained greater
than 65°F (18°C). If this is not possible due to lack of heat load, then the load banks must be used to offset
the cooling load during startup. See
Target Refrigerant Level in Sight Glasses at Outdoor Temperatures
6. Close the Liebert® DSE disconnect switch.
6 Piping and Refrigerant Requirements
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