MCAC-UTSM-2010-10
Test Operation
Installation
31
8. Additional refrigerant charge
After the vacuum drying process is carried out, the additional refrigerant charge process need 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 indoor and outdoor unit. Refer the following
formula to calculate the charge volume.
For 12
k
Btu/h (throttle part in outdoor unit)
Diameter of liquid pipe (mm)
6.4
Formula
V=15g/m×(L-5)
For 18, 24, 36, 48, 60k
Btu/h (throttle part in indoor unit)
Diameter of liquid pipe (mm)
6.4
9.5
12.7
Formula
V=30g×(L-5)
V=65g×(L-5)
V=115g×(L-5)
V: Additional refrigerant charge volume (g).
L : The length of the liquid pipe (m).
Note:
Refrigerant may only be charged after performed the vacuum drying process.
Always use gloves and glasses to protect your hands and eyes during the charge work.
Use electronic scale or fluid infusion apparatus to weight refrigerant to be recharged.
Be sure to avoid
extra refrigerant charged, it may cause liquid hammer of the compressor or protections.
Use supplementing flexible pipe to connect refrigerant cylinder, pressure gauge and outdoor unit. And
The refrigerant should be charged in liquid state. Before recharging, The air in the flexible pipe and
manifold gauge should be exhausted.
After finished refrigerant recharge process, check whether there is refrigerant leakage at the connection
joint part.(Using gas leakage detector or soap water to detect).
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