Additional Refrigerant Charge - Fisher FSAIF-CP-91AE3 Technical Manual

water might penetrated into pipeline.
3. Construction period is long, and rain water might
penetrated into pipeline.
4. Rain water might penetrate into pipeline during
construction.
Procedures of special vacuum drying are as follows:
1. Vacuum drying for 1 hour.
2. Vacuum damage, filling nitrogen to reach 0.5Kgf/cm2 .
Because nitrogen is dry gas, vacuum damage could
achieve the effect of vacuum drying, but this method
could not achieve drying thoroughly when there is too
much moisture. Therefore, special attention shall be drawn
to prevent the entering of water and the formation of
condensate water.
3. Vacuum drying again for half an hour.
If the pressure reached -755mmHg, start to pressure
leakage test. If it cannot reached the value, repeat vacuum
damage and vacuum drying again for 1 hour.
4. Leakage test: After the vacuum degree reaches
-755mmHg, stop vacuum drying and keep the pressure for
1 hour. If the indicator of vacuum gauge does not go up,
it is qualified. If going up, it indicates that there is moisture
or leak source.

7. 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 be-
tween indoor and outdoor unit. Refer the following
formula to calculate the charge volume.
Diameter of liquid pipe (mm)
6.35
9.52
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 ham-
mer of the compressor or protections.
•
Use supplementing flexible pipe to connect refriger-
ant 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 connec-
tion joint part.(Using gas leakage detector or soap
water to detect).
Formula
V=12g/m×(L-5)
V=24g/m×(L-5)
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