McQuay RCM20D

1-12
VACUUMING AND CHARGING
Purging the piping and the indoor unit
Except for the outdoor unit which is pre-charged with
refrigerant R22, 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 -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
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 (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 5m, then additional charge after
vacuuming is not necessary. If the piping length is more
than 5m, then use the additional charge valve as indicated
in the table below.
Additional charge in gram
SERVICE PORT
OUTDOOR UNIT
3 WAYS VALVE
FLARE
NUT
REFRIGERANT
PIPING
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 cylin-
der valve.
• Disconnect the service hose from service port. Put back
the service port cap.
ALLEN
KEY
MODEL R22 CHARGE(g/m)
7m 10m 15m 20m
20D/20DR 30/50 75/125 150/250 225/375
25D/25DR 76/100 190/250 380/500 570/750
30D/30DR 100/100 250/250 500/500 750/750
40D/40DR 100/100 250/250 500/500 750/750
50D/50DR 100/100 250/250 500/500 750/750
CED1099 (10~14/E) 2/1/01, 3:48 PM12