McQuay 5CKWS 10CR Installation Manual page 13

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 fan coil unit
Except for the water source heat pump unit which is pre-
charged with refrigerant, the fan coil 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 fan coil unit and
water source heat pump 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 water source heat pump 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 pre-charged of R410A in water source heat pump
unit is suitable for standard pipe of length up to 2 meter
for 5WSS 07/10/15/16/20 AR.
• When the piping is more than the stated standard pipe
length, add additional charge of 18.5 gram/meter for
5WSS 07/10/15/16/20 AR.
• 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 cyl-
inder.
• 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
Fan Coil Unit
Vacuum
pump
1-9
Allen key
Flare nut
Service Port
Water source heat pump
unit 3 ways valve
Liquid side
Discharge
Valve
Gas side
Suction
valve
Open
Close
Hi
Low
Close
Refrigerant Piping
Water Source
Heat Pump Unit
Close