# 504,465M
Page 5
Plumbing
If the SCU14M unit is being installed with a new indoor
coil and line set, the plumbing connections should be
made as outlined in the section that follows. If an existing
line set and/or indoor coil will be used to complete the
system, refer to the section entitled
Flushing Existing
Line Set and Indoor Coil
on page 6.
If this unit is being
matched with an approved line set or indoor coil
which was previously charged with R22 refrigerant,
the line set and coil must be flushed prior to installa-
tion.
Field refrigerant piping consists of liquid and suction lines
from the condensing unit (sweat connections).
Plumbing Connections Using New Indoor Coil and
Line Set
If refrigerant lines are to be routed through a wall, seal
and isolate the opening so vibration is not transmitted to
the building.
NOTE
– Line length should be no greater than 50'. Use
Table 2 to select line set diameters to ensure oil return to
the compressor.
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4
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3
0
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4
1
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6
3
0
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9
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(
2
4
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4
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2
2
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Refrigerant Line Kits
Table 2
Polyol ester (POE) oils used with R410A
refrigerant absorb moisture very quickly. It is
very important that the refrigerant system be
kept closed as much as possible. DO NOT
remove line set caps or service valve stub
caps until ready to make connections.
WARNING
Brazing Connection Procedure
1. The end of the refrigerant line must be cut square and
its internal shape must remain round. The line must
be free of nicks or dents and must be deburred (I.D.
and O.D.).
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-copper brazing or 45% silver alloy for
copper-to-brass or copper-to-steel brazing) which are
rated for use with R410A refrigerant. Wrap a wet cloth
around the valve body and the copper tube stub.
Remove light maroon washers from service valves
and shield light maroon stickers to protect them
during brazing. Braze the line set to the service valve.
4. Quench the joint with water or a wet cloth to prevent
heat damage to the valve core and opening port.
The
tube end must stay bottomed in the fitting during
final assembly to ensure proper seating, sealing,
and rigidity.
5. Flush line set and evaporator if required (refer to
Flushing Existing Line Set and Indoor Coil
on page
6).
6. Install the provided thermal expansion valve
(approved for use with R410A refrigerant) in the liquid
line at the indoor coil. (See the
Installing Thermo
Expansion Valve
section that follows.)
7. Install the provided filter drier (approved for use with
R410A refrigerant) in the liquid line as close as
possible to the expansion device.
Do not leave the
drier uncapped for more than 10 – 15 minutes
prior to brazing, evacuation, and leak testing.
Installing Thermo Expansion Valve
Before opening any system, make sure the
pressure in the system is brought to and
remains at atmospheric pressure. Failure to
comply can result in system damage and/or
personal injury.
WARNING
1. Insert suction line splice between evaporator and
suction line with the equalizer port pointing upwards.
To prevent plugging the equalizer line with oil, the
equalizer port must be between a 10:00 and 2:00
position.
