Unit Installation
Unit Installation
Charging Hose
Most field-charging is done using standard service hoses. Hoses are made in different colors with
different working pressures and with different leak rates but the most important point is the presence
or absence of hoses
This slows evacuation and vapor charging dramatically. In most cases the Shredder depressor can
be removed but it is simpler to have one set of hoses with and one set without Shredder depressors
Hose selection is important depending whether the system is being evacuated or charged. Charging
liquid from the cylinder into the liquid line should be carried out using an open hose connected to an
unrestricted fitting. This will reduce charging time.
The proper refrigerant charge should follow the volume as recommended by manufacturer , addtional
charge for extended length installation can follow general guideline below.
If the installer cannot find the correct charge but the system must be started, refrigerant should be
carefully added to the system until reasonable sub-cooling is measured in the liquid line and reasonable
suction superheat is measured at the compressor suction. Suction and discharge pressures must be
monitored carefully during the charging process.
Additional Chage
Based on liquid pipe size per meter length:
Liquid line size kg
1/2” 0.10
5/8” 0.17
3/4” 0.26
7/8” 0.37
Above is the recommendation, actual charge level may be different due to the different application
and ambient condition.
Refrigerant R410A : special precaution
R410A is HFC refrigerant which has Zero Ozone Depletion Potential (ODP = 0). The working
pressure of this refrigerant is 1.6 times higher than refrigerant (R22), thus proper installation /
servicing is essential
i) Characteristic
Mixture of composition by weight : R32(50%) and R125(50%)
R410A liquid and vapor components have different compositions when the fluid evaporates or
condenses. Hence, when leak occurs and only vapor leaks out, the composition of the refrigerant
mixture left in the system will change and subsequently affect the system performance.
It is NOT recommended to add new refrigerant to leaked system.
System shall be evacuated thoroughly and recharging with liquid refrigerant (original mixture
composition of R410A ).
Polyol-ester (POE) oil is used as lubricant for R410A compressor. As the water will react with POE
oil and become acid.
Extra precaution
must be taken to avoid exposing the R410A system to moist air.
How much refrigerant?
