Split system using a remote condenser will require a
copper discharge and copper liquid line for each
compressor circuit. The following instructions should be
followed to ensure proper installation. A/C systems,
utilizing R-410A refrigerant, have higher operating
pressures than systems utilizing R-407C.
All refrigeration piping should be installed with high
temperature brazed joints suitable for R-410A
refrigerant. Use standard refrigeration practices for
piping supports, leak testing, dehydration and charging of
the refrigeration circuits. Oil traps must be included every
20 feet in the vertical risers and the refrigerant lines must
be sloped ¼ inch for every 10 feet in the horizontal lines
to ensure proper oil return to the compressor.
Wrap wet rags around the pipes between the areas to be
soldered and any nearby refrigeration components to
keep excessive heat from traveling through the pipe and
causing damage. Clear all pipe connections of debris and
prepare the connections for soldering. Use only “L” or “K”
grade refrigerant copper piping. Be careful not to allow
solder/piping debris to get inside refrigerant lines. Silver
solder containing a minimum of 15% silver is
recommended. Dry nitrogen should be flowing through
the tubing while soldering at a rate of not less than 1-2
CFM (.03 - .06 M
3
/minute).
Refrigerant lines for split systems must be sized
according to the piping distance between the evaporator
and the condenser(s). Each valve, fitting and bend in the
refrigerant line must be considered in this calculation.
Pipe sizes are given for “equivalent feet”, not linear feet. Do
not confuse the terminologies. For example, a 7/8”
standard 90° elbow has an equivalent length of 1.5 feet; a
7/8” branch Tee has an equivalent length of 3.5 feet.
These corrections must be accounted for when sizing your
piping. Refer to the following table for determining the
standard equivalent lengths, in feet, of straight pipe.
Equivalent Length (ft) of Straight Pipe
OD
(In.)Line
Size
Globe
Valve
Angle
Valve
90º
Elbow
45º
Elbow
Tee
Line
Tee
Branch
1/2
9.0
5.0
0.9
0.4
0.6
2.0
5/8
12
6.0
1.0
0.5
0.8
2.5
7/8
15
8.0
1.5
0.7
1.0
3.5
1-1/8
22
12
1.8
0.9
1.5
4.5
1-3/8
28
15
2.4
1.2
1.8
6.0
1-5/8
35
17
2.8
1.4
2.0
7.0
2-1/8
45
22
3.9
1.8
3.0
10
2-5/8
51
26
4.6
2.2
3.5
12
3-1/8
65
34
5.5
2.7
4.5
15
3-5/8
80
40
6.5
3.0
5.0
17
CyberAiR DX Floor Mounted IOM Manual
If the condenser is installed above the evaporator, the
discharge line should include a p-trap at the lowest point
in the piping. The highest point in the discharge line
should be above the condenser coil and should
include an inverted trap to help prevent oil and liquid
from flooding back to the compressor during off cycles.
If the condenser is installed below the evaporator, an
inverted trap the height of the evaporator coil is
required on the liquid line to help prevent oil and liquid
from flooding back to the compressor during off cycles.
CAUTION
Liquid line length should not exceed 150
equivalent feet.
NOTE
Ensure proper condenser selection in order
to maintain reasonable sub-cooling
temperatures.
Refer to the remote condenser IOM manual,
supplied with the equipment, for detailed
installation instructions.
Refer to the following refrigerant line size tables for
recommended line sizing.
NOTE
In the following tables, the line sizes are for
individual refrigeration circuits. STULZ
CyberAir- DX units must have two separate
pairs of refrigeration lines. (One per
compressor circuit.)
Recommended Liquid Line Sizes for R-410A
Refrigerant
CFS Model
No./Total BTU
Capacity
Receiver to Evaporator (Equivalent Ft.)*
50’
or less
100’
or less
150’
or less
021 / 72,000
1/2
1/2
1/2
028 / 96,000
1/2
5/8
5/8
035 / 120,000
1/2
5/8
5/8
053 / 180,000
5/8
7/8
7/8
070 / 240,000
7/8
7/8
7/8
088 / 300,000
7/8
7/8
7/8
105 / 360,000
7/8
7/8
1 1/8
*Equivalent Ft. accounts for the linear pipe length as well as
equivalent length of Valves, Elbows & Tee’s as shown in the
previous table.
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