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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.
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 performance are about the same as the re-
frigerant 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 mois-
ture compared with R22, make sure to temporarily cover
the ends of the tubing prior to installation.
Vacuuming is necessary to eliminate all moisture and air from the system. The series II Outdoor Unit is provided with flare
valve fittings.
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 as
shown in the diagram. 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.
•
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.
•
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)
ii)
iii) Refrigerant cylinder/charging cylinder
iv) Vacuum pump c/w adapter
v)
vi) Refrigerant recovery machine
•
Filter-dryer must be installed along the liquid line for all
R407C air conditioners. This is to minimise the contamina-
tion of moisture and dirt in the refrigerant system. Filter-
dryer must be of molecular sieve type. For a heat-pump sys-
tem, install a two-way flow filter dryer along the liquid line.
VACUUMING AND CHARGING
Charging
Before charging, the vacuum must be held at 500 microns
Hg for at least 15 minutes, then break vacuum by charging
R-22 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.
1-11
Manifold gauge and charging hose
Gas leak detector
Flare tools
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