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5.8.2 Pipe wrapping
To avoid condensation and water leakage, the
connecting pipe must be wrapped with tape to ensure
isolation from the air.
Tape
Insulation material
Liquid pipe
Gas pipe
When wrapping insulation tape, each circle should press
half of the previous circle of tape. Do not wrap the tape
too tightly to avoid reducing the thermal insulation effect.
After completing the pipe insulation work, seal the holes
in the wall with sealing material.
5.8.3 Protective measures of the pipeline
The refrigerant pipe will swing, expand or shrink
during operations. If the pipe is not fixed, the load will
be concentrated in a certain part, which may cause
the deformation or rupture of the refrigerant pipe.
The suspended connecting pipes shall be well
supported, and the distance between supports shall
not exceed 1m.
The outdoor pipes shall be protected against
accidental damage. If the length of the pipe exceeds
1m, a gusset plate must be added for protection.
5.9 Refrigerant Charging
WARNING
Use only R410A as the refrigerant. Other
substances may cause explosions and
accidents.
R410A contains fluorinated greenhouse
gases, and the GWP value is 2088. Do not
discharge the gas into the atmosphere.
When charging the refrigerant, make sure
you wear protective gloves and safety
glasses. Be careful when you open the
refrigerant piping.
If the power supply of some units is off, the
charging program cannot be completed
normally.
If this is a multi-unit outdoor system, the
power supply for all outdoor units should be
turned on.
Make sure the power supply is turned on 12
hours before operations so that the
crankcase heater is properly energized. This
is also to protect the compressor.
Make sure all connected indoor units have
been identified.
Charge the refrigerant only after the system
Fig.5.42
has not failed the gas tightness tests and
vacuum drying.
Volume of refrigerant charged must not
exceed the designed amount.
Calculating additional refrigerant charge
The additional refrigerant charge required depends on
the lengths and diameters of the outdoor and indoor
liquid pipes. Table below shows the additional
refrigerant charge required per meter of equivalent pipe
length for different diameters of pipe. The total
additional refrigerant charge is obtained by summing
the additional charge requirements for each of the
outdoor and indoor liquid pipes, as in the following
formula, where T1 to T8 represent the equivalent
lengths of the pipes of different diameters. Assume
0.5m for the equivalent pipe length of each branch
joint.
Table 5.7
Liquid piping
Diameter
(mm OD)
Additional refrigerant charge R (kg) = (T1@Φ6.35) × 0.022
+ (T2@Φ9.52) × 0.057 + (T3@Φ12.7) × 0.110 + (T4@Φ
15.9) × 0.170 + (T5@Φ19.1) × 0.260 + (T6@Φ22.2) ×
0.360 + (T7@Φ 25.4) × 0.520 + (T8@Φ28.6) × 0.680.
33
NOTE
Additional refrigerant charge per
meter of equivalent length of
liquid piping (kg)
Φ6.35
0.022
Φ9.52
0.057
Φ12.7
0.110
Φ15.9
0.170
Φ19.1
0.260
Φ22.2
0.360
Φ25.4
0.520
Φ28.6
0.680
V.1
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