24
How to Use Predetermined Line Sizing
First, read the previous section,
When to Use
Predetermined Line Sizing
, to decide if this
method is applicable. Next, consult Table 2
below for pipe diameters.
Examine Figure 6 below to determine the
acceptable line dimensions associated with
the pipe diameters determined in Table 2
below. The figure is shown as total available
riser height versus total equivalent line
length for the liquid line. The curve
identifies a region of acceptable piping
configuration when the predetermined line
sizes are selected for any model in the table.
A piping configuration above the curve falls
outside the assumptions used to determine
the line size and will result in a loss of sub-
cooling, and additional pressure losses in the
suction and hot gas lines.
The total equivalent line length definition
includes the height of vertical rise, pressure
drop through elbows and accessories, and
horizontal
line
length,
so
elbows,
accessories, and vertical rise must be
considered when determining horizontal
length available from the total equivalent
line length.
The figure below is presented in terms of the
liquid line, but it assumes that the suction
line length is similar, as these lines are
commonly routed together to minimize the
space and cost required for split system
installation.
Before using this table read the
When to Use Predetermined Line
Sizes
section. Do not assume that
these line sizes are appropriate for
every case. Consult ASHRAE
Handbook
–
Refrigeration
for
generally accepted system piping
practices. The AAON
Refrigerant
Piping Calculator
in Ecat32 can be
used for job specific line sizing.
CAUTION
Summary of Contents for CB-024
Page 40: ...40 Refrigerant Piping Diagrams Figure 12 A C only piping AHU above CU ...
Page 41: ...41 Figure 13 A C only piping AHU below CU ...
Page 42: ...42 Figure 14 Modulating hot gas reheat piping AHU above CU ...
Page 43: ...43 Figure 15 Modulating hot gas reheat piping AHU below CU ...
Page 44: ...44 Figure 16 Hot gas bypass piping AHU above CU ...
Page 45: ...45 Figure 17 Hot gas bypass piping AHU below CU ...
Page 46: ...46 Figure 18 Modulating hot gas reheat with hot gas bypass piping AHU above CU ...
Page 47: ...47 Figure 19 Modulating hot gas reheat with hot gas bypass piping AHU below CU ...
Page 48: ...48 Figure 20 Heat pump piping AHU above CU ...
Page 49: ...49 Figure 21 Heat pump piping AHU below CU ...
Page 50: ...50 Figure 22 Heat pump with modulating hot gas reheat piping AHU above CU ...
Page 51: ...51 Figure 23 Heat pump with modulating hot gas reheat AHU below CU ...