Installation and Maintenance Manual

Installation—Piping
24 UV-SVN02C-EN
Install the refrigerant suction and liquid lines as described
in the condensing unit installation instructions. The
thermal expansion valve (TXV) is factory-installed on the
Unit Ventilator.
Note: The R-410A direct expansion (DX) refrigerant coil
includes a factory-mounted adjustable thermal
expansion valve (TXV) set to 90 psig superheat and
an equalizing tube.
Piping should be run straight out through the back of the
unit. Access piping knockouts are located in the rear
panels of the unit, as shown in Figure 5, p. 13 through
Figure 9, p. 17.
Recommended refrigerant line connections for various
unit combinations are given in Table 9, p. 21. Typical
Superheat Charging Charts are shown in the Trane Service
Facts found in the condensing unit section manual.
Refrigerant charge weights can also be determined with
your local Trane account manager using a valid Trane
Selection Program.
Steam Piping
When air, water or another product is heated, the
temperature or heat transfer rate can be regulated by a
modulating steam pressure control valve. Since pressure
and temperature do not vary at the same rate as load, the
steam trap capacity, which is determined by the pressure
differential between the trap inlet and outlet, may be
adequate at full load, but not some lesser load.
There are detailed methods for determining condensate
load under various operating conditions. However, in
most cases this is not necessary if the coils are piped as
shown in Figure 15. Follow the procedure documented in
the ASHRAE Systems Handbook, Steam Systems.
Modulating Water Valves (Option)
The actuator on the valve is a 24 V, three-point floating
valve. The actuator can be easily removed from the valve
body by pressing in on the locking tab and rotating the
actuator 45° counter-clockwise (see Figure 16). The two-
way valves are bi-directional flow. The three-way valves
can be mixing or diverting (see Figure 17).
Note: The actuator must be removed if soldering is being
conducted near the valve. High heat may cause
damage to the actuator’s plastic body/
mechanisms.
On applications without factory-installed piping packages
(option), it is important to remove the cartridge assembly
from the valve body with the provided tool (see Figure 18,
p. 25).
Figure 15. Steam piping
Vacuum Equalizer
H= 12"
minimum
F&T Trap
See text for sizing
Gravity flow to
vented receiver
Coil
To Condensate
return
Temp. Regulating Valve
Figure 16. Remove modulating valve actuator by
pressing in tab (inset) and turning actuator
45° clockwise
UV-SVN02_-EN.book Page 24 Thursday, January 24, 2013 4:48 PM