Vacuuming And Charging; Purging The Piping And The Indoor Unit; Additional Charge; Charge Operation - McQuay M5WM Series Installation And Maintenance Manual

Vacuuming and Charging

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. (See Figure 18.)
• 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
(-29.9"Hg).
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.
Figure18. 3-way Suction Valve on Outdoor Unit

Additional Charge

The refrigerant is pre-charged in the outdoor unit. If the
tubing length between the indoor and outdoor unit is no
more than 25ft. than an additional charge after
evacuation is not necessary. If the tubing length is more
than 25ft., use additional R410A as indicated in Table 5.
Table 5. Additional R410A ounces (when tubing length is
more than 25 feet
Model 26' -33'
10F 1.2
15F 1.2
20F 1.2
25F 2.8
10FR 1.6
15FR 1.6
20FR 2.0
25FR 4.0
IM-5WMF(SEER13)-0706
34' – 40' 41' – 50'
2.0 -
2.0 -
2.0 3.5
5.3 9.4
2.8 -
2.8 -
3.5 5.8
7.0 11.8

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. See Figure 20.
• 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 form service port. Put
back the service port cap.
Figure 19. Vacuuming Schematic
Figure 20. Charging Schematic
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