Daikin MAGNITUDE WME-D, Установка, эксплуатация и обслуживание, Страница: 51 / 56

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STARTUP AND MAINTENANCE
Refrigerant Charging
NOTICE
Proper refrigerant charge is essential for optimal unit operation,
unit performance, and environmental protection.
Refrigerant charging is to be performed only by licensed, if
required by local codes and regulations, or qualified personnel
who are familiar with local codes and regulations and are
experienced with this type of equipment.
CAUTION
When moving refrigerant to/from the chiller using an auxiliary
tank, a grounding strap must be used. An electrical charge
builds when halo-carbon refrigerant travels in a rubber hose. A
grounding strap must be used between the auxiliary refrigerant
tank and the end sheet of the chiller (earth ground), which will
safely take the charge to the ground. Damage to sensitive
electronic components could occur if this procedure is not
followed.
If a unit is low on refrigerant, you must first determine the cause
before attempting to recharge the unit. Locate and repair any
refrigerant leaks. Soap works well to show bubbles at medium
size leaks but electronic leak detectors are needed to locate
small leaks.
Charging Procedure
The units are factory-charged with R-515B. The full refrigerant
charge will vary depending on chiller configuration and design
conditions. Obtain the refrigerant charge information from the unit
nameplate.
Use the following procedure if recharging in the field is necessary.
Charging or check valves should always be used on charging
hoses to limit refrigerant loss and prevent frostbite. Ball valve
type recommended. The only accurate way to adjust the charge
is to recover and charge by weight. Charge to 80-85% of normal
charge before starting the compressors. The charge can be
added at any load condition between 25 to 100 percent load per
circuit.
NOTICE
The charge can be added at any load condition between 25 to
100 percent load per circuit.
CAUTION
Evaporator water-flow MUST be established while charging the
unit. Failure to following this procedure may damage equipment.
1 . Start the system and observe operation.
2 . Trim the charge to the recommended liquid line sub-cooling
(refer to technical data sheet to trim charge or adjust
settings).
3 . Use standard charging procedures (liquid only) to top off
the charge.
4 . Check the sight glass to be sure there is no refrigerant
flashing.
— If the unit is at steady full load operation and bubbles
are visible in the sight glass, then check liquid
subcooling.
— If subcooling is low, add charge to clear the sight
glass. Once the subcooler is filled, extra charge will not
lower the liquid temperature and does not help system
capacity or efficiency.
NOTICE
Overcharging of refrigerant will raise the compressor discharge
pressure due to filling of the condenser tubes with excess
refrigerant.
Additional Charging Requirements
In addition to conventional charging procedures, the following
requirements shall be followed.
• Ensure that contamination of different refrigerants does not
occur when using charging equipment.
• Hoses or lines shall be as short as possible to minimize the
amount of refrigerant contained in them.
• Cylinders shall be kept in an appropriate position according
to the instructions.
• Ensure that the REFRIGERATING SYSTEM is earthed prior
to charging the system with refrigerant.
• Label the system when charging is complete (if not already).
• Extreme care shall be taken not to overfill the
REFRIGERATING SYSTEM.
• Prior to recharging the system, it shall be pressure-tested
with the proper purging gas and evacuated appropriately.
The system shall be leak-tested on completion of charging
but prior to commissioning. A follow up leak test shall be
carried out prior to leaving the site.