Daikin FH15CBV1L Technical Manual page 65

Special Precautions When Dealing With Refrigerant R410A Unit
(1) What is New Refrigerant R-410A?
R-410A is a new HFC refrigerant which does not damage the ozone layer. The working pressure of
this new refrigerant is 1.6 times higher than conventional refrigerant (R22), thus proper
installation / servicing is essential.
(2) Components
Mixture weight composition R32(50%) and R125(50%)
(3) Characteristic
• R-410A liquid and vapour components have different compositions when the fluid
evaporates of condenses. Hence, when leak occurs and only vapor leaks out, the composition
of the refrigerang mixture left in the system will change and subsequently affect the system
performance. DO NOT add new refrigerant to leaked system. It is recommended that the system
should be evacuated thoroughly before recharging with R-410A.
• When refrigerant R-410A is used, the composition will differ depending on whether it is in
gaseous or liquid phase. Hence when charging R-410A, ensure that only liquid is being withdrawn
from the cylinder or can. This is to make certain that only original composition of R-410A is being
charged into the system.
• POE oil is used as lubricant for R-410A compressor, which is different from the mineral oil used for
R22 compressor. Extra precaution must be taken not to expose the R-410A system too long to
moist air.
(4) Check List Before Installation / Servicing
• Tubing
Refrigerant R-410A is more easily affected by dust of moisture compared with R22, make
sure to temporarily cover the ends of the tubing prior to installation.
• Compressor oil
No additional charge of compressor oil is permitted.
• Refrigerant
No other refrigerant other that R410A
• Tools (size of service port is different from R22 system)
Tools specifically for R-410A only (must not be used for R22 or other refrigerant)
i) Gauge manifold and charging hose
ii) Gas leak detector
iii) Refrigerant cylinder/charging cylinder
iv) Vacuum pump c/w adapter
v) Flare tools
vi) Refrigerant recovery machine
(5) Handling and Installation Guildelines
Like R22 system, the handling and installation of R-410A system are closely similar. All
precautionary measures; such as ensuring no moisture, no dirt or chips in the system, clean brazing
using nitrogen, and thorough leak check and vacuuming are equally important requirements.
However, due to it hydroscopic POE oil, additional precautions must be taken to ensure optimum
and trouble free system operation.
(a) During installation or servicing, avoid prolong exposure of the internal part of the refrigerant
system to moist air. Residual POE oil in the piping and components can absorb moisture from
the air.
(b) Ensure that the compressor is not exposed to open air for more than the recommended time
specified by its manufacturer (typically less than 10 minutes). Removed the seal plugs only when
the compressor is about to be brazed.
(c) The system should be thoroughly vacuumed to 1.0 Pa (700mmHg) or lower. This vacuuming
level is more stringent than R22 system so as to ensure no incompressible gas and moisture
in the system.
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