After the vacuum drying process is carried out, the additional refrigerant charge process needs to be
performed. The outdoor unit is factory charged with refrigerant. The additional refrigerant charge volume is
decided by the diameter and length of the liquid pipe between the indoor and outdoor unit. Refer to the
following formula to calculate the charge volume.
V=Additional refrigerant charge volume (oz).
L=The length of the liquid pipe (ft).
• Refrigerant may only be charged after the vacuum drying process is performed.
• Always use gloves and glasses to protect your hands and eyes during the charging process.
• Use an electronic scale, or a fluid infusion apparatus, to properly weigh refrigerant to be recharged. Be
sure to avoid over-charging the system with refrigerant, as it could cause a leak, damage to the compressor,
or result in personal injury.
• Use supplemental flexible pipe to connect the refrigerant cylinder, pressure gauge, and outdoor unit. The
refrigerant should only be charged in a liquid state.
• After the refrigerant recharging process, check for refrigerant leaks at the connection joint. (By using either
a gas leakage detector or soapy water to detect).
12. Additional Refrigerant Charge
OUTDOOR UNIT
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Table - 5
NOTE:
There are two ways to verify the correct refrigerant charge. The most commonly
used method is to adjust the refrigerant charge based on the subcooling range. The second
method is rarely used, but it is being included for reference only. Multiply the length of the
liquid pipe and the empirical coefficient (the coefficient is determined by the pipe diameter)
to verify the correct charge.
