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B. Refrigerant Line Design and Sizing
Consider the length of the piping required between the out-
door and indoor units. The maximum allowable line length is
100 ft. Select proper liquid and vapor line sizes from Table 4.
Contact your local representative if assistance is required for
design details and proper piping practices.
Table 4 — Piping Selection and
Refrigerant Charge Data
LENGTH 0F PIPING — FT*
OUTDOOR
0-25
UNIT
Line Size (in. OD)
541A
L
V
5
1
5
120
/
1
/
8
8
5
3
3
180
1
/
/
8
8
Approximate System Charge
120
30
180
37
LEGEND
L — Liquid Line
V — Vapor Line
*Approximately 4 elbows assumed in determining pipe sizes.
†Maximum length of interconnecting piping is 100 ft.
**Approximate system charge is for estimating only. It includes charge
requirements for one outdoor unit, matching indoor coil, and intercon-
necting piping. See Preliminary Charge section on page 10.
NOTE: If there is a vertical separation between indoor and outdoor
units, see Table 3. Double vapor line riser may be required.
Carefully evaluate any vapor risers at minimum load condi-
tions to ensure proper compressor oil return. If the indoor
unit is above the outdoor unit, the riser will function as a hot
gas riser. If the outdoor unit is above the indoor unit, the
riser is a suction riser. Design and construct a double riser if
necessary. Contact your local representative if assistance is
required.
Fig. 4 — Compressor Mounting
MAXIMUM
25-60
60-100†
LIQUID
LINE OD
(in.)
L
V
L
V
3
5
5
/
1
/
1
/
/
8
8
8
8
5
3
5
1
1
/
/
/
/
4
4
8
8
Maximum
Charge —
lb**
38
46
45
59
C. Liquid Line Piping Procedure
Pipe the system liquid line as follows:
WARNING: Unit is pressurized with a holding
charge of refrigerant. Recover R-22 holding charge
before removing runaround liquid piping loop. Failure
to recover holding charge before removing piping loop
could result in equipment damage and severe injury.
1. Open service valves in sequence:
a. Discharge service valve on compressor.
b. Suction service valve on compressor.
c. Liquid line valve.
5
/
8
3
2. Remove
/
4
port.
3. Attach refrigerant recovery device and recover hold-
lb
ing charge.
48
62
4. Remove runaround loop.
5. Connect system liquid line from liquid connection of
outdoor (541A) unit to indoor unit liquid line connec-
tions. See Fig. 5 for typical piping and wiring. Select
proper field-supplied bi-flow filter driers and install
in the liquid line. See Fig. 6. Install a field-supplied
liquid moisture indicator between the filter drier(s)
and the liquid connections on the indoor (524A-H)
unit. Braze or silver alloy solder all connections. Pass
nitrogen or other inert gas through piping while mak-
ing connections to prevent formation of copper oxide.
(Copper oxides are extremely active under high tem-
perature and pressure. Failure to prevent collection
of copper oxides may result in system component
failures.)
D. Vapor Line Piping Procedure
Connect system vapor line to the vapor line stub on the out-
door unit and the vapor stubs on the indoor unit. At the
indoor unit, construct vapor piping branches as shown in
Fig. 7 for good mixing of the refrigerant leaving the indoor
coil during cooling. This will ensure proper TXV (thermo-
static expansion valve) bulb sensing.
Where vapor line is exposed to outdoor air, line must be insu-
lated. See Table 5 for insulation requirements.
—
5
—
1
/
-in. flare cap from liquid valve Schrader
4
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