SYSTEMP – Installation Operation Manual (IOM SYSTEMP rev.N)

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9.2 COOLING CIRCUIT SIZING
9.2.1 TYPES OF PIPING TO BE USED
The pipes must be made of copper that is suitable for direct expansion cooling circuits as required by standard EN 12735-1.
Annealed copper coils may be used (diameters up to 7/8"), as well as hard-drawn copper bars.
In conformity with the EN14276-1 and EN14276-2 standards, the minimum recommend thickness for gas supply line piping,
in particular where there are curves, for air condensed units using R410a refrigerant, it must be equal to values present in the table
attached here below.
Copper pipe specications
External diameter Ø Minimum pipe thickness Minimum curvature radius
De t r
Inches mm mm mm
3/8'' 10 0.8 20
1/2'' 12 0.8 20
5/8'' 16 1 26
3/4'' 18 1 27
7/8'' 22 1 66
1-1/8'' 28 1.2 100
9.2.2 CALCULATION OF THE EQUIVALENT PIPE LENGTH
For correctly sizing the unit cooling lines it is necessary to calculate the equivalent length of refrigerant piping. When re-
ferring to equivalent length it means the linear length of the pipes coupled to the equivalent lengths of additional elements of the
circuit, such as curves, therefore, the formula for calculation is as follows:
TOTAL EQUIVALENT LENGTH (m) = LINEAR LENGTH OF PIPE SECTIONS (m) + EQUIVALENT
LENGTHS OF CIRCUIT COMPONENTS (m)
The following table includes equivalent length of the most common components of a cooling line:
Equivalent lengths of the cooling circuit components
External diameter Ø
Curve
45°
Curve
90°
Elbow
90°
Curve
180°
T-
Fitting
Inches mm m
3/8'' 10 0.24 0.26 0.39 0.50 0.56
1/2'' 12 0.26 0.28 0.43 0.54 0.61
5/8'' 16 0.27 0.31 0.46 0.62 0.76
3/4'' 18 0.30 0.40 0.58 0.80 0.92
7/8'' 22 0.35 0.46 0.70 0.92 1.10
1-1/8'' 28 0.45 0.55 0.82 1.10 1.38