Special Precautions When Dealing With R410A Unit; Vacuuming And Charging; Charge Operation - McQuay 5CKY10C 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
conditioner which designed to operate with R410A.
• Since R410A is a mixed refrigerant, any additional
refrigerant must be charged in liquid state for better
performance compared to gas state.
• 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.
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 changing gauge and stop the vacuum
pump.
• On the outdoor unit, open the suction valve and liquid
valve (in anti-clockwise direction) with 4mm key for
hexagon sacked screw.

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,
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
correctly. 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
Indoor Unit
1-11
Allen Key
Flare Nut
Service Port
Outdoor Unit
3 Ways Valve
Liquid Side
Discharge Valve
Gas Side
Suction Valve
Open
Hi
Low
Close
Liquid Side
Discharge Valve
Gas Side
Check
Suction Valve
Valve
Hi
Low
Open
Close
Refrigerant Piping
Outdoor Unit
Close
Close
Outdoor Unit
Open
Open