23
NSZ/NDZ INSTALLATION MANUAL
The Envision series comes with a holding charge. The
charge must be adjusted in the field 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.
Connection to Air Coil
Figures 1 and 2 illustrate typical Envision Split installations.
The Line Set Sizes table shows typical line set diameters
and maximum length. As in all R-410A equipment, a
reversible liquid line filter drier is required to insure all
moisture is removed from the system. This drier should be
replaced whenever “breaking into” the system for service.
All line sets should be insulated with a minimum of 1/2 in.
closed cell insulation. All insulation should be painted with
UV resistant paint or covering to insure long insulation life.
Refrigeration
Replace caps after
opening system
Service ports for
attaching refrigerant
gauges
Insulated
Suction Line
Braze
Connection
Liquid
Line
ccw
ccw
Figure 13: Typical Split System Refrigerant Line
Connections
Position
Description
System
Service
Port
CW - Full In
Shipping Position
Closed
Open
CCW - Full Out 1/2 turn CW
Service Position
Open
Open
CCW - Full Out
Operation Position
Open
Closed
TXV ("IN" toward condensing unit)
Equalizer Bulb
Suction
Liquid
TXV has internal check valve
Figure 14: Attaching the Air Coil
Fasten the copper line set to the blower coil unit as
instructed by the coil installation instructions shown in
Figure 14. Nitrogen should be bled through the system at 2
to 3 PSI to prevent oxidation inside the refrigerant tubing.
Use a low silver phos-copper braze alloy on all brazed
connections.
Braze line set to the service valve stubs on the inside
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. Envision 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.
