Special Precautions When Dealing With R410A Unit; Vacuuming And Charging - McQuay G Series Installation Manual

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 compres-
sor. 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.
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 center 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 -760mmHg.
Caution
• If the gauge needle does not move to -760mmHg, be sure
to check for gas leaks (using the refrigerant
detector) at flare type connection of the indoor and outdoor
unit and repair the leak before proceeding to the next step.
• Close the valve of the charging 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.
Additional charge
The refrigerant is pre-charged in the outdoor unit. If the
piping length is less than 7.62m (25ft), then additional charge
after vacuuming is not necessary. If the piping length is more
than 7.62m (25ft), then use the additional charge valve as indi-
cated in the table.
Charge operation
This operation must be done by using a gas cylinder and a
precise weighing machine. The additional charge is topped-up
into the outdoor unit using the suction valve via the service
port.
• Remove the service port cap.
• Connect the low pressure side of the charging gauge to the
suction service port center of the cylinder tank and close
the high pressure side of the gauge. Purge the air from the
service hose.
• Start the air conditioner unit.
• Open the gas cylinder and low pressure charging valve.
• When the required refrigerant quantity is pumped into the
unit, close the low pressure side and the gas cylinder valve.
• Disconnect the service hose from service port. Put back the
service port cap.
• Use tools and materials exclusively for refrigerant R410A.
Tools exclusively for R410A are manifold valve, charg-
ing 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.

VACUUMING AND CHARGING

Indoor Unit
Vacuum
pump
Additional charge in gram (For R22 models)
07 / 09 / 10 / 15G
07 / 09 / 10 / 15GR
Additional charge in gram (For R410A models)
07 / 09 / 10 / 15G
07 / 09 / 10 / 15GR
Indoor Unit
1-7
Allen key
Flare nut
Service Port
Outdoor Unit 3 ways valve
Liquid side
Discharge
Valve
Gas side
Suction
valve
Open
Hi
Low
Close
Model
10m/32.8ft
35
50
20G
35
20GR
60
25G
90
25GR
120
Model
10m/32.8ft
35
45
20G
35
20GR
55
25G
80
25GR
110
Liquid side
Discharge Valve
Gas side
Suction
Check
Valve
Valve
Hi
Low
Close
Refrigerant Piping
Outdoor Unit
Close
Close
12m/39.4ft 15m/49.2ft
65 –
90 –
65 110
110 185
165 280
220 370
12m/39.4ft 15m/49.2ft
60 –
80 –
60 100
100 165
150 255
200 335
Outdoor Unit
Open
Open