RTAC-SVX01J-EN 55
Installation - Mechanical — Remote Evaporator Option
The RTAC 140-250 ton outdoor unit with the Remote
Evaporator option is shipped as two pieces: the outdoor
unit (condensing) and the evaporator. Short suction line
connections are provided with the outdoor condensing
unit.The remote evaporator is shipped complete, with
factory-mounted electronic expansion valves, water
temperature sensors, suction pressure transducers, liquid
level control sensors, evaporator flow switch, all factory
wired to a ribbon cable. Solenoid valves and drain valves
are wired to a relay board in the terminal box.The
installing contractor is required to provide and install the
following:
• 2-wire, twisted shielded communication line between
the remote evaporator terminal box and the
Condensing Unit’s control panel
• 4-wire connection from evaporator terminal box to
condensing unit control panel for flow switch wiring
(see Figure 27, p. 63)
• 115 VAC single phase power supply to the remote
evaporator terminal box
• 2 liquid lines
• 2 suction lines
• Suction accumulator as specified
Note: A unit ordered as a remote evaporator must also be
ordered with either the wide or low ambient option.
The fan inverters are necessary for proper control.
System Configuration and
Interconnecting Refrigerant
Piping
The system may be configured in any of the four
arrangements shown in Figure 23, p. 56.The
configurations and their associated elevations, along with
the total distance between the remote evaporator and the
compressor/condenser section, play a critical role in
determining suction and liquid line sizes.This will also
affect field refrigerant and oil charges. Consequently, there
are physical limits which must not be violated if the system
is to operate as designed. Please note the following
requirements for field installation:
1. The remote evaporator MUST be matched with its
respective outdoor condensing unit.
2. The circuit number on the outdoor condensing unit
must match the circuit number on the evaporator, i.e.
circuit #1 on the outdoor condensing unit must be
connected with circuit#1ontheremote evaporator
and likewise for circuit #2. RTAC Circuit Capacities are
shown in General DataTables.
3. Piping between the evaporator and outdoor unit can
not exceed 200 actual feet and/or an equivalent length
of 300 feet.
Note: The latter includes the equivalent length of all
associated field installed fittings, valves,
accessories and straight lengths of interconnecting
piping.
4. Horizontal portions of suction lines must be downward
sloping toward the compressor at least 1/2 inch for
each 10 feet run.This promotes the movement of oil in
the direction of gas flow.
5. Suction lines must be insulated.
6. The line sizes defined are to be used only for 40-60 F
leaving water temperature and/or full load ice-making
applications.
7. Figure 23, p. 56, drawing 1 depicts an installation
where the remote evaporator elevation is the same as
that of the outdoor condensing unit.The suction and
liquid lines are horizontal or down flowing only.
The suction and liquid lines can be put under ground or
in a trench. The temperature of the suction lines must
never exceed the temperature of the compressor. The
line can be below the compressors a maximum of 15 ft.
8. Figure 23, p. 56, drawing 2 shows a variation to
drawing 1.The remote evaporator and outdoor
condensing unit are at the same elevation but
interconnecting piping may be installed up to 15 feet
above the base elevation. Refer to
Table 31, p. 59 to
determine the required length of the suction
accumulator line. A full size suction accumulator is
required at the evaporator and 50% of the value is
required at the condensing unit.
9. A refrigerant drain valve is installed at the bottom of
the evaporator for freeze protection.This drain valve is
a normally open, pilot operated valve which remains
closed unless there is a potential freezing situation
detected via low evap temperatures or low water
temperatures or a power failure. If the drain valve is
opened the installed suction accumulator must be
capable of holding the entire evaporator charge. Refer
to
Table 31, p. 59 for sizing.
10. For installations where the remote evaporator is at a
lower elevation than the outdoor condensing unit as
shown in Figure 23, p. 56, drawing 3, the elevation
difference is not to exceed 100 feet. An inverted liquid
line trap at the condensing unit is required to prevent
unwanted free cooling.The apex of the liquid line trap
NOTICE:
Equipment Damage!
If the circuits are crossed, serious equipment damage
could occur.
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