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English
SPECIAL PRECAUTIONS WHEN DEALING WITH R407C UNIT
• R407C is a zeotropic refrigerant mixture which has zero ozone depletion potential and thus conformed to the Montreal
Protocol regulation. It requires Polyol ester oil (POE) oil for its compressor's lubricant. Its refrigerant capacity and perfor-
mance are about the same as the refrigerant R22.
• POE oil is used as lubricant for R407C compressor, which is different from the mineral oil used for R22 compressor.
During installation or servicing, extra precaution must be taken not to expose the R407C system too long to moist air.
Residual POE oil in the piping and components can absorb moisture from the air.
• Refrigerant R407C is more easily affected by dust of moisture compared with R22, make sure to temporarily cover the
ends of the tubing prior to installation.
• No additional charge of compressor oil is permitted.
• No other refrigerant other than R407C.
• Tools specifically for R407C only (must not be used for R22 or other refrigerant)
i) Manifold gauge 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
• Filter-dryer must be installed along the liquid line for all R407C air conditioners. This is to minimise the contamination of
moisture and dirt in the refrigerant system. Filter-dryer must be of molecular sieve type. For a heat-pump system, install a
two-way flow filter dryer along the liquid line.
Vacuuming
Before vacuuming, perform leak check for refrigeration circuit.
After the system piping are properly connected, connect the
flexible hoses to the correct charging nipples. Ensure that
flexible hose from charging nipples are connected to the
vacuum pump via standard servicing valves and pressure
gauges (gauge manifold). Vacuum the air conditioner system
to at least 500 microns Hg. Do not start the unit when the
system is engaged in vacuuming.
Charging
Before charging, the vacuum must be held at 500 microns Hg
for at least 15 minutes, then break vacuum by charging R22
or R407C refrigerant. Operate the unit for 15 minutes and
ensure the refrigerant charges is of correct by monitoring
running current, gas and liquid line pressures. Suction and
discharge pipe pressure should be in the region of 75 psig and
275 psig generally.
After ensuring the system is correctly charged, remove flexible
hose from charging nipples and replace caps.
VACUUMING AND CHARGING
Vacuuming is necessary to eliminate all moisture and air from the system.
SPECIAL PRECAUTIONS WHEN DEALING WITH R410A UNIT
R410A 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.
• Never use refrigerant other than R410A in an air condi-
tioner which designed to operate with R410A.
• POE oil is used as lubricant for R410A compressor, which
is different from the mineral oil used for R22 compressor.
During installation or servicing, extra precaution must be
taken not to expose the R410A system too long to moist
air. Residual POE oil in the piping and components can
absorb moisture from the air.
• To prevent mischarging, the diameter of the service port
on the flare valve is different from that of R22.
• Use tools and materials exclusively for refrigerant R410A.
Tools exclusively for R410A are manifold valve, charging
hose, pressure gauge, gas leak detector, flare tools, torque
wrench, vacuum pump and refrigerant cylinder.
• As an R410A air conditioner incurs higher pressure than
R22 units, it is essential to choose the copper pipes cor-
rectly. Never use copper pipes thinner than 0.8mm even
though they are available in the market.
• If the refrigerant gas leakage occurs during installation /
servicing, be sure to ventilate fully. If the refrigerant gas
comes into contact with fire, a poisonous gas may occur.
• When installing or removing an air conditioner, do not
allow air or moisture to remain in the refrigerant cycle.
• R407C must be charged as liquid. Usually R407C cylinder is equipped with a dip-pipe for liquid withdrawal.
If there is no dip-pipe, the cylinder should be inverted so as to withdraw liquid R407C from the valve.
• Do not top-up when servicing leak, as this will reduce the unit performance. Vacuum the unit thoroughly and
then charge the unit with fresh R407C according to the amount recommended in the specification.
! Caution
