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SPECIAL PRECAUTIONS WHEN DEALING WITH R410A UNIT
•
R410A is a near azeotrope refrigerant blend of hydro fluorocarbon (HFC) which is environmental friendly. It has Zero
Ozone Depletion Potential (ODP=0) and this conforms to Montreal Protocol regulations. It has no flame propagation and
a low toxic refrigerant (rated as A1 by ARI). R410A is a mixture of R32 (50%) and R125 (50%).
•
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.
•
Refrigerant R410A 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 only is permitted.
•
No refrigerant other than R410A is permitted.
•
Tools designed specifically for R410A only.
i) Manifold gauge and charging hose
ii) Gas leak detector
iii) Refrigerant cylinder/charging cylinder
iv) Vacuum pump c/w adaptor
v) Flare tools
vi) Refrigerant recovery machine
•
R410A must be charged as liquid. Usually R410A 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 R410A 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 R410A according to the amount recommended in the specification.
•
Do not touch the compressor or refrigerant piping when the chiller is running. If necessary wear protective gloves.
Purging the piping and the indoor unit
Except for the outdoor unit which is pre-charged with
refrigerant, the indoor unit and the refrigerant
connection pipes must be air-purged because the air
containing moisture that remains in the refrigerant cycle may
cause malfunction of the compressor.
•
Remove the caps from the valve and the service port.
•
Connect the centre of the charging gauge to the vacuum
pump.
•
Connect the charging gauge to the service port of the
3-way valve.
•
Start the vacuum pump. Evacuate for approximately 30
minutes. The evacuation time varies with different
vacuum pump capacity. Confirm that the charging gauge
needle has moved towards -76mmHg (0~76mmHg).
Caution
If the gauge needle does not move to 0~76mmHg, be
sure to check for gas leaks (using the refrigerant
detector) at flare type connection of the indoor and out-
door unit and repair the leak before proceeding to the
next step.
•
Close the valve of the changing gauge and stop the
vacuum pump.
•
On the outdoor unit, open the suction valve (3 way) and
liquid valve (2 way) (in anti-clockwise direction) with
4mm key for hexagon sacked screw.
! ! ! ! ! CAUTION
VACUUMING AND CHARGING
Additional charge
The refrigerant is pre-charged in the outdoor unit. If the
piping length is less than 7.62m (25 ft), then additional
charge after vacuuming is not necessary. If the piping length
is more than 7.62m (25 ft), then use the additional charge
valve as indicated in the table below.
Vacuum
Pump
1-10
Flare Unit
Allen Key
Service Port
Outdoor Unit
3 Ways Valve
Liquid Side
Indoor Unit
Gas Side
Open
Hi
Low
Close
Refrigerant Piping
Outdoor Unit
Discharge
Valve
Close
Suction
Valve
Close
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