Trane CLCP Manual page 11

Assembly & Installation
Refrigerant Coil Piping 1. Install moisture indicator/sight
glass between the expansion valve
and filter-drier. The moisture
TYPE FD COILS HAVE BEEN
indicator/ sight glass must be sized
DEHYDRATED AND CHARGED WITH
to match the size of the liquid line
A HOLDING CHARGE OF DRY
at the thermal expansin valve.
NITROGEN. 10-20 PSIG TO
2. Size liquid line shutoff valve with an
PREVENT LEAKS AND SYSTEM
access port using the selected
CONTAMINATION, DO NOT BREAK
liquid line OD, and install it close to
THE SEALS UNTIL THE COIL IS
the condenser.
INSTALLED.
3. Minimize use of other valves, tube
bends and reducers since these
items tend to increase pressure
1. Follow accepted refrigeration piping
drop and to reduce subcooling at
practices and safety precautions for
the expansion valve.
typical refrigerant coil piping and
4. The Thermal Expansion Valve (TEV)
components.Specific recommen-
must be selected for proper size
dations are provided with the
and capacity. The size of the TEV
condensing units, including
should cover the full range of
instructions for pressure-testing,
loadings. Check that the valve will
evacuation, and system charging.
successfully operate at the lightest
General recommendations for
load condition. Select expansion
component selection and line
valves with external equalizer
sizing follow.
connections, and those designed
2. Leak-test the entire refrigeration
to operate against a back pressure
system after all piping is complete.
of 20 pounds per square inch
3. Charge the unit according to
higher than actual evaporator
approximate weight requirements,
pressure.
operating pressures and super-
5. Install the TEV directly in the coil
heat / subcoling measurements.
liquid connection (distributor)
4. Adjust the thermal expansion valve
provided.
Setting if necessary.
The liquid distributor must be in a
true vertical position.
General Refrigerant Piping
Suction Line Components
Recommendations
Install suction line pressure tap on the
IMPORTANT: REFER TO THE NOTE
leaving side of the evaporator coil near
ON THE INSIDE FRONT COVER OF
the TEV sensing bulb location.
THIS MANUAL REGARDING
Accurate superheat measurement and
HANDLING OF REFRIGERANTS.
thermal expansion valve adjustment
demands that suction pressure be
measured near the evaporator coil.
Liquid Line Components
Trane recommends the use of a
properly sized liquid line filter-drier
installed upstream from the expansion
valve and as close to the
evaporatorcoil as possible. Base filter-
drier selection on a minimum
pressure drop of 2 psi at the design
condition.
16
Liquid Line Sizing
All compressors have a Refrigerant
Charge Limit (RCL) that must not be
exceeded. Since the RCL and
pressure drop are in direct conflict with
each other, Trane recommends that the
liquid line be sized as small as
possible, while maintaining a low
enough pressure drop to ensure
5℉(3℃) of subcooling at the expansion
valve.
Suction Line Sizing
Suction line tubes must be sized to
maintain refrigerant vapor velocities
that are high enough to ensure oil
entertainment under all operating
conditions.
It is not necessary to pitch horizontal
suction lines toward the compressor
when refrigerant coils is used with
Trane condensing units that are
designed with a gas trap in the suction
line just prior to the compressor.
Assembly & Installation
Figure 14
CAUTION
Typical Piping for Refrigerant Coil
To avoid equipment malfuntion, SOLENOID
LIQUID VALVE
use care when brazing or solder-
ing so that distributor tubing is not
STRAINER
restricted or blocked. To braze
Thermostatic Expansion Valves
(TXV) avoid direct flame (figure 15)
LIQUID LINE
to the valve body and avoid
FROM RECEIVER
excessive heat on diaphragm. As
EXPANSION
an extra precaution. a wet cloth may
VALVE
be around the body and element
during brazing operation.
NOTE : THE EXPANSION VALVE SHOULD BE INSTALLED
DIRECTLY ON THE DISTRBULTOR.
Figure 15
Solder Technique
OK
TDE
Note: Flame should heat away from TXV element
EXPANSION VALVE
SIGHT
CAPILLARY TUBES
GLASS
EXPANSION VALVE
THERMAL BULBS
EXPANSION VALVE
EQUALIZER LINES
SUCTION LINE
TO COMPRESSOR
Min.5%Ag
Max.700℃
（1300℉）
OK
﹛
1/2-5/8in
OD
12-16mm
﹛
3/4-7/8in
OD
18-22mm
﹛
3
1-1 / in
8
OD
25-35mm
17