Trane CLCP Euro 25 Installation Operation & Maintenance page 29

Refrigerant Coil Piping
TYPE FD COILS HAVE BEEN DEHYDRATED AND
CHARGED WITH A
NITROGEN. 20 PSIG TO PREVENT LEAKS AND SYSTEM
CONTAMINATION. DO NOT BREAK THE SEALS UNTIL
THE COIL IS INSTALLED.
1. Follow accepted refrigeration piping practices and safety
precautions for typical refrigerant coil piping and
components. Specific recommendations are provided with
the condensing units,
pressure-testing, evacuation, and system charging.
General recommendations for component selection and
line sizing follow.
Leak-test the entire refrigeration system after all piping is
2.
complete.
3. Charge the unit according to approximate weight
requirements, operating pressure and superheat/sub
cooling measurements.
4. Adjust the thermal expansion valve setting if necessary.
General refrigerant Piping Recommendations
General refrigerant Piping
Recommendations
IMPORTANT: REFER TO THE NOTE ON THE INSIDE
FRONT COVER OF
HANDLING OF REFRIGERANT.
Liquid Line Component
Trane recommends the use of a properly sized liquid line
filter-drier installed upstream from the expansion valve and as
close to the evaporator coil as possible. Base filter drier
selection on a minimum pressure drop of 2 psi at the design
condition.
1. Install moisture indicator/sight
expansion valve
indicator/sight glass must be sized to match the size of the
liquid line at the thermal expansion valve.
2. Size liquid line shutoff valve with an access port using the
selected liquid line OD, and install it close to the
condenser.
3.
Minimize use of the other valves, tube bends and reducers
since these items tend to increase pressure drop and to
reduce subcooling at the expansion valve.
4. The Thermal Expansion Valve (TEV) must be selected for
proper size and capacity. The size of the TEV should cover
HOLDING CHARGE
including instructions
THIS MANUAL REGARDING
glass between
and filter-drier. The
the full range of loadings. Check that the valve will
successfully operate at the lightest load conditions. Select
expansion valve with external equalizer connections, and
those designed to operate against a back pressure of 20
OF DRY
psi, higher than actual evaporator pressure.
5. Install the TEV directly in the coil liquid connection
(distributor) provided. The liquid distributor must be in a
true vertical position.
Suction Line Components
for
Install suction line pressure tap on the leaving side of the
evaporator coil near the TEV sensing bulb location. Accurate
superheat measurement and thermal expansion valve
adjustment demands that suction pressure be measured near
the evaporator coil.
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 5ºF(3ºC) of subcooling at
the expansion valve.
Suction Line Sizing
Suction line tubes must be sized to maintain refrigerant
vapour 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 are used with Trane
condensing units that are designed with a gas trap in the
suction line just prior to the compressor.
the
moisture
29
Piping and Connection