Fujitsu AirStage AB12, Service Manual

Page: 133 / 199

9-5 Precautions for installation 9-6 Precautions for Servicing
COPPER PIPES
(1) It is necessary to choose adequate materials.
If new synthetic oil is mixed with residual oil(ex : min-
eral type) ,they may deteriorate, and block the capil-
lary tubes, or cause the compressor to fail.
So it is desirable that the amount of residual oil in
connection pipes is less than 40 mg/10 m.
Thickness of copper pipes is shown below.
(2) Control contaminants
Since new synthetic oil is easily influenced by conta-
minants (water, residual oil, etc.), it must be handled
with care more than the conventional lubricating oil.
(3) Refrigerant charge
When charging refrigerant, take into account the
slight change in the composition of the gas and liquid
phases, and always charge from the liquid phase
side whose composition is stable.
(4) Correct refrigerant charge
As there are air conditioner models using different
refrigerant such as R22, R407C, make sure to check
and not to use wrong refrigerant when installing and
servicing.
(5) Air purge
Always use a vacuum pump to purge the air.
In the case of Fujitsu General's new refrigerant
model, refrigerant for purging the air is not charged in
the outdoor unit at the factory.
Nominal Outer diameter Thickness
diameter (inch) (mm) (mm)
1/4 ø 6.35 0.8
3/8 ø 9.52 0.8
1/2 ø 12.70 0.8
5/8 ø 15.88 1.0
3/4 ø 19.05 1.0
1. Countermeasure when the refrigerant leaks
As R407C is geotropic refrigerant, the composition of
the remaining refrigerant changes when the refrigerant
leaks.
Therefore, recharging refrigerant cannot be done.
Recover the remaining refrigerant and charge the spec-
ified amount of new refrigerant.
2. Never use the existing refrigerant piping
The existing piping used for R22 cannot be used for the
cycle of HFC series refrigerant as the conventional min-
eral oils are adhering to the piping.
Due to the deteriorated mineral oils, compressor may
be damaged.
Therefore, basically use a brand new piping.
However,in case of the existing piping buried in the wall
and replacement with new piping is difficult, wash the
piping fully with detergent.
3. Replacement of refrigeration cycle parts
As refrigeration cycle parts are basically different from
conventional parts, be sure to use the parts suitable for
the refrigerant when replacing.
For R407C, the materials are being reviewed.
4. Charging wrong refrigerant
As there are air conditioner models using different
refrigerant such as R22, R407C, make sure to check
and not to use wrong refrigerant when installing and
servicing.
5. Storage of parts
When storing parts, make such treatment as packing
the parts in bags so as to avoid dusts, water, etc.
6. Replacing parts
When replacing parts, be sure to check if the parts are
suitable for the refrigerant(model).
For most refrigeration cycle parts which have same
appearance, the inside material is changed.
When changing compressor, complete brazing within
15 minutes after opening the cap. After opening the
cap, the moist air enters the compressor, and oil
absorbs the moisture causing sludge. When changing
dryer, complete brazing within one hour after the pack-
age of dryer is opened.
The desiccant starts to absorb the water content as
soon as the package of dryer is opened.
If it absorbs too much water content when replacing, it
cannot absorb fully the water content in the refrigerat-
ing cycle.
1/8 ø 28.58 1.2 1
– 133 –