Refrigeration - Trane 2GN Series Installer's Manual

REFRIGERATION

The 2GN Series comes with a holding charge. The charge must
be adjusted in the fi eld based on performance. Refrigeration
piping on the split consists of installing a brazed copper line
set between the blower coil unit and the unit's split compressor
section. To select the proper tube diameters for the installation,
refer to the Line Set Sizes table. Line sets over 60 feet long
are not recommended because of oil return and pressure drop
problems. The suction line must always be insulated. Handle
and route the line sets carefully to avoid kinking or bending
the tubes. If the line set is kinked or distorted and it cannot
be formed back into its original shape, the bad portion of the
pipe should be replaced. A restricted line set will affect the
performance of the system.
Figure 14: Attaching the Air Coil
TXV ("IN" toward condensing unit)
TXV has internal check valve
POSITION
CW - FULL IN
CCW - FULL OUT 1/2 TURN CW
CCW - FULL OUT
18-GL07D1-4
Equalizer Bulb
Suction
Liquid
DESCRIPTION
SHIPPING POSITION
SERVICE POSITION
OPERATION POSITION
Braze line set to the service valve stubs on the outside front
of the split cabinet as shown in Figure 13. Nitrogen should
be bled through the system at 2 to 3 PSI to prevent oxidation
contamination. Use a low silver phos-copper braze alloy on
all brazed connections. 2GN Series split units are shipped
with a factory charge and service valves are not to be opened
until the line set has been leak tested, purged and evacuated.
Schrader cores should be removed before brazing. A heat
sink should be used on the service valves and TXV to prevent
damage caused by excessive heat.
Figure 13: Typical Split System Refrigerant Line Connections
Service ports for
attaching refrigerant
gauges
Replace caps after
opening system
ccw
SERVICE
SYSTEM
PORT
CLOSED OPEN
OPEN OPEN
OPEN CLOSED
2GN SPLIT INSTALLER'S GUIDE
Insulated
Suction Line
ccw
Braze
Connection
Liquid
Line
23