506859-01Issue 1236Page 6 of 32
Install unit away
from windows
Two 90° elbows installed in lineset
will reduce lineset vibration
Figure 7
Brazing Connection Procedure
1. Cut ends of refrigerant lines square (free from nicks or
dents). Debur the ends. The pipe must remain round;
do not pinch end of line.
Refrigerant Piping
If the 4SCU16/18LS unit is being installed with a new indoor
coilandlineset,the refrigerant connections shouldbemade
as outlined in this section. If an existing line set and/or
indoor coil will be used to complete the system, refer to this
section as well as the section that follows entitled- Flushing
Existing Line Set and Indoor Coil.
2. Before making line set connections, use dry nitrogen to
purge the refrigerant piping. This will help to prevent
oxidation and the introduction of moisture into the
system.
3. Use silver alloy brazing rods (5% or 6% silver alloy for
copper-to-copperbrazingor 45% silver alloyforcopper-
to-brass or copper-to-steel brazing) which are rated for
use with R410A refrigerant.
4. Remove the Schrader core assemblies before brazing
to protect them from damage due to extreme heat.
Replace the cores when brazing is complete.
5. Remove light maroon washers from service valves
and shield light maroon stickers to protect them during
brazing. Wrap a wet cloth around the valve body and
copper tube stub to protect it from heat damage.
6. Braze the line set to the service valve. Quench the
joints with water or a wet cloth to prevent heat damage
tothevalve core andopening port. The tube end must
stay bottomed in the tting during nal assembly
to ensure proper seating, sealing, and rigidity.
7. Install the thermal expansion valve which is sold
separately and which is approved for use with R410A
refrigerant in the liquid line at the indoor coil (see
Refrigerant Metering Device on page 10).
Following are some points to consider when placing and
installing a high-efciency outdoor unit:
Placement
Be aware that some localities are adopting sound ordinances
based on how noisy the unit is at the neighbor’s home, not
at the original installation. Install the unit as far as possible
fromthe property line. When possible, do not installthe unit
directly outside a bedroom window. Glass has a very high
level of sound transmission. Figure 7 shows how to place
the outdoor unit and line set to reduce line set vibration.
Line Set Isolation
Illustrations on pages 7 and 8 demonstrate procedures which
ensure proper refrigerant line set isolation. Figure 8 shows
how to install line sets on horizontal runs. Figure 9 shows
how to make a transition from horizontal to vertical. Figure
10 shows how to install line sets on vertical runs.
Outside Unit Placement
and Installation
Table 2
Refrigerant Line Set Diameters (in.)
For installations exceeding 50’, contact
Technical Services
Liquid Line
Btuh Line Set Length and Size
12 . 25 . 50 . 75 . 100 .
24,000 3/8 3/8 3/8 3/8 3/8
36,000 3/8 3/8 3/8 3/8 1/2
48,000 3/8 3/8 3/8 1/2 1/2
60,000 3/8 3/8 3/8 1/2 1/2
Suction Line
Btuh Line Set Length and Size
12 . 25 . 50 . 75 . 100 .
24,000 3/4 7/8 3/4 7/8 7/8
36,000 7/8 7/8 7/8 7/8 1-1/8
48,000 7/8 7/8 7/8 1-1/8 1-1/8
60,000 1/8 1/8 1-1/8 1-1/8 1-1/8
