Full Product Manual

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 refrigerantcharge 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 fluid infusion apparatus to weigh refrigerant to be recharged. Be sure to
avoid extra refrigerant being charged, as it may cause damage to the compressor, cause a leak, or
could result in personal injury.
• Use supplementing flexible pipe to connect refrigerant cylinder, pressure gauge and outdoor unit.
The refrigerant should be charged in liquid state.
• After the refrigerant recharge process, check for refrigerant leakage at the connection joint. (Using
a gas leakage detector or soapy water to detect).
12. Additional Refrigerant Charge
OUTDOOR UNIT
mrcool.com | Page 16
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 included for reference only. Multiply the length of the liquid pipe and the empirical coecient (the
coecient is determined by the pipe diameter) to verify the correct charge. This method is rarely used.