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5.8.3 Protective measures for 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
refrigerant pipe to deform or rupture.
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.
NOTE
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
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
has not failed the gas tightness tests and
vacuum drying.
Volume of refrigerant charged must not
exceed the designed amount.
Calculating
the
additional
calculation for liquid piping (R1 kg)
The additional refrigerant charge required depends on
the lengths and diameters of the outdoor and indoor
liquid pipes. The 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.
so
that
the
refrigerant
charge
37
Additional refrigerant charge R1 (kg) = (T1@Φ6.35) ×
0.022 + (T2@Φ9.52) × 0.057 + (T3@Φ12.7) × 0.110 +
(T4@Φ15.9) × 0.170 + (T5@Φ19.1) × 0.260 + (T6@Φ
22.2) × 0.360 + (T7@Φ 25.4) × 0.520 + (T8@Φ28.6) ×
0.680.
Calculating the additional refrigerant charge quantity
for outdoor unit (R2 kg)
The additional refrigerant charge is required depending
on the capacity of connected outdoor units, In case of a
multi-outdoor-unit system, add the sum of the individual
outdoor unit charge amount. Select the refrigerant
quantity for each outdoor unit from the following table.
Table 5.5
HP
8 10 12 14 16 18 20 22 24 26 28 30 32
Additional
refrigerant
0 0 0 0 0 0 0 0 0 7 9 9 9
Charge (kg)
The additional refrigerant charge (R2 kg) = W1+W2+W3
W1: master unit additional refrigerant charge amount;
W2: Slave unit 1 additional refrigerant charge amount;
W3: Slave unit 2 additional refrigerant charge amount;
The example below illustrates the piping selection
procedure for a system consisting of three outdoor units
(900+670). Based on the capacity of each outdoor
unit, Select the refrigerant quantity from the table
5.4,
W1=9kg;
W2=9kg;
W3=0kg.
refrigerant charge quantity for outdoor unit R2 =W1 +W2
+W3 =18kg.
Calculating the total additional refrigerant charge
quantity (R kg).
Total additional refrigerant charge amount (R) is equal
to the sum of R1 and R2, calculate the amount of
refrigerant to be charged according to the formula
below:
R (kg) = R1+ R2.
Maximum additional refrigerant charge quantity
Ensure that the total additional charge quantity should not
exceed the max. additional refrigerant charge quantity.
NOTE
Strictly follow the conditions shown in the
above calculation method for refrigerant
charging amount, and determine that the
additional amount shall not exceed the
maximum
refrigerant
shown in the table 5.6. If the calculated value
of additional refrigerant exceeds the limits
shown in the table 5.6, the total length of the
pipeline
construction
shortened and the refrigerant charging
amount shall be recalculated to meet the
requirements shown in the table 5.6.
The maximum refrigerant addition shown in
the table 5.6 is based on the recommended
combination.
Table 5.6
Maximum additional
HP
HP
refrigerant charge
quantity kg
8
30.9
18
10
32.6
20
12
35.5
22
14
37.0
24
16
38.8
26
The
additional
additional
amount
scheme
shall
be
Maximum additional
refrigerant charge
quantity kg
41.9
41.9
41.9
41.9
69.0
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