Daikin FHC50JEV1K [18/24] Additional charge

ADDITIONAL CHARGE

SPECIAL PRECAUTIONS WHEN CHARGING UNIT WITH SCROLL COMPRESSORS

The refrigerant is pre-charge in the outdoor unit. If the piping length is less than 7.5m, then additional charge after vacuuming

is not necessary. When the piping length is more than 7.5m, use the table below.

Cooling only

Example:

FDM30JEV1K & RD30JEV1K with 13m piping length, additional piping length is 5.5m. Thus,

Additional charge = 5.5[m] x 55[g/m]

= 302.5[g]

These precautions are intended for use with Scroll compressors only with R22 and R410A refrigerants but are not applied to

others competitive Scroll compressors.

Scroll compressors have a very high volumetric efÞ ciency and quickly pump a deep vacuum if there is insufÞ cient refrigerant

in the system or if refrigerant is added too slowly. Operation with low suction pressure will quickly lead to very high discharge

temperatures. While this process is happening, the scrolls are not being well lubricated – scrolls depend on the oil mist in the

refrigerant for lubrication. A lack of lubrication leads to high friction between the scroll ß anks and tips and generates additional

heat. The combination of heat of compression and heat from increased friction is concentrated in a small localized discharge

area where temperatures can quickly rise to more than 300°C. These extreme temperatures damage the Scroll spirals and the

orbiting Scroll bearing. This damage can occur in less than one minute especially on larger compressors. Failure may occur

in the Þ rst few hours or the damage done during Þ eld charging may show up some time later. Other typical Þ eld charging

The proper refrigerant charge should follow the volume as recommended by manufacturer and recommendation should be

followed by the installer.

1. Charging procedures – Single phase compressors

Evacuate the system to -760mmHg. To reduce evacuation time, use short, large diameter hoses and connect to unrestricted

service ports on the system. Quality of vacuum cannot be determined by time – a reliable vacuum gauge must be used. (etc.

electronic vacuum gauge)

Turn the refrigerant cylinder upside down, purge the charging hose and charge liquid through the liquid line charging port

until refrigerant no longer ß ows or until the correct charge has been weighed in. If additional charge is required start the

system and slowly bleed liquid into the suction side until the system is full.

It recommends charging liquid in a CONTROLLED manner into the suction side until the system is full.