Trane Rtaaiom3 Manual

							41RTAA-IOM-3
Evaporator Piping
Figure 22 illustrates typical evaporator
piping components. Components and
layout will vary slightly, depending on
the location of connections and the
water source.
Caution: The chilled water
connections to the evaporator are
to be “victaulic” type connections.
Do not attempt to weld these
connections, as the heat generated
from welding can cause internal
damage to the evaporator.
The chilled water connections are on
the left side of the unit. If it is necessary
for the chilled water piping to enter the
unit from the right side, elbows can be
used to route the piping 1800 over the
top of the evaporator, as shown in
Figure 22, for RTAA 130-200 units only.
A vent is provided on the top of the
evaporator at the return end. Be sure to
provide additional vents at high points
in the piping to bleed air from the
chilled water system. Install necessary
pressure gauges to monitor the
entering and leaving chilled water
pressures.
Caution: To prevent damage to
chilled water components, do not
allow evaporator pressure
(maximum working pressure) to
exceed 215 psig.
Provide shutoff valves in lines to the
gauges to isolate them from the
system when they are not in use. Use
rubber vibration eliminators to prevent
vibration transmission through the
water lines.
If desired, install thermometers in the
lines to monitor entering and leaving
water temperatures. Install a balancing
valve in the leaving water line to
control water flow balance. Install
shutoff valves on both the entering and
leaving water lines so that the
evaporator can be isolated for service.
A pipe strainer should be installed in
the entering water line to prevent
waterborne debris from entering the
evaporator.
Figure 22
Suggested Piping for
Typical RTAA Evaporator
VentsValved
Pressure
Gauge
DrainUnion
Vibration
EliminatorFlow
Switch
(Optional)
Balancing ValveGate Valve Union
Water
Strainer Vibration
Eliminator
Gate Valve
RTAA 130-200
with Opposite-Side Connections
(View from end opposite control panel) 
						

							42RTAA-IOM-3
Evaporator Piping
Components
“Piping components” include all
devices and controls used to provide
proper water system operation and
unit operating safety. These
components and their general
locations are given below.
Entering Chilled Water Piping
[  ] Air vents (to bleed air from system).
[  ] Water pressure gauges with shutoff
valves.
[  ] Vibration eliminators.
[  ] Shutoff (isolation) valves.
Thermometers (if desired).
[  ] Clean-out tees.
[  ] Pipe strainer.
Caution: To prevent tube damage
install strainer in evaporator water
inlet piping.
Leaving Chilled Water Piping
[  ] Air vents (to bleed air from system).
[  ] Water pressure gauges with shutoff
valves. Vibration eliminators.
[  ] Shutoff (isolation) valves.
[  ] Thermometers.
[  ] Clean-out tees.
[  ] Balancing valve.
[  ] Flow Switch (If desired)
Caution: To prevent evaporator
damage, do not exceed 215 psig
(14.6 bar) evaporator water
pressure.
Evaporator Drain
A 3/4 drain connection is located
under the outlet end of the evaporator.
This may be connected to a suitable
drain to permit evaporator drainage
during unit servicing. A shutoff valve
must be installed on the drain line.
Evaporator Flow Switch
Chilled water flow protection is
provided by the UCM without the need
for a chilled water flow switch. A flow
switch for chilled water is strictly
discretionary but if not installed, a
signal still must be sent to the chiller to
indicate that water flow has been
established, e.g. chilled water pump
motor starter auxiliary contacts.
If additional chilled water flow
protection is desired, use a field-
installed flow switch or differential
pressure switch with the pump
interlock to sense system water flow.
Install and wire the flow switch in series
with the chilled water pump motor
starter auxiliaries (refer to “Electrical
Wiring”).
Specific connection and schematic
wiring diagrams are shipped with the
unit. Some piping and control
schemes, particularly those using a
single water pump for both chilled and
hot water, must be analyzed to
determine how and or if a flow sensing
device will provide desired operation.
Follow the manufacturer’s
recommendations for selection and
installation procedures. General
guidelines for flow switch installation
are outlined below
1. Mount the switch upright, with a
minimum of 5 pipe diameters of
straight horizontal run on each side.
Do not install close to elbows,
orifices or valves.
Note: The arrow on the switch must
point in the direction of flow.
2. To prevent switch fluttering, remove
all air from the water system.
Note: The UCM provides a 6-second
time delay after a “loss-of-flow”
diagnostic before shutting the unit
down. Contact a qualified service
representative if nuisance machine
shutdowns persist. 
						

							43RTAA-IOM-3
3. Adjust the switch to open when
water flow falls below nominal.
Evaporator data is shown in Figure
23. Refer to Table 1 for minimum
flow recommendations. Flow switch
contacts are closed on proof of water
flow.4. Install a pipe strainer in the entering
evaporator water line to protect
components from waterborne
debris.
Figure 23
RTAA 130 thru 400
Evaporator Water Pressure Drop 
						

							44RTAA-IOM-3
Water Treatment
Using untreated or improperly treated
water in these units may result in
inefficient operation and possible tube
damage. Consult a qualified water
treatment specialist to determine
whether treatment is needed. The
following disclamatory label is
provided on each RTAA unit:
Customer Note
The use of improperly treated or
untreated water in this equipment may
result in scaling, erosion, corrosion,
algae or slime. The services of a
qualified water treatment specialist
should be engaged to determine what
treatment, if any, is advisable. The
Trane Company warranty specifically
excludes liability for corrosion, erosion
or deterioration of Trane equipment.
Trane assumes no responsibilities for
the results of the use of untreated or
improperly treated water, or saline or
brackish water.
Caution: Do not use untreated or
improperly treated water.
Equipment damage may occur.
Water Pressure Gauges
Install field-supplied pressure gauges
(with manifolds, whenever practical) as
shown in Figure 22. Locate pressure
gauges or taps in a straight run of pipe;
avoid placement near elbows, etc. Be
sure to install the gauges at the same
elevation on each shell if the shells
have opposite-end water connections.
To read manifolded pressure gauges,
open one valve and close the other
(depending upon the reading desired).
This eliminates errors resulting from
differently calibrated gauges installed
at unmatched elevations.
Water Pressure Relief Valves
Install a water pressure relief valve in
the evaporator inlet piping between the
evaporator and the inlet shutoff valve,
as shown in Figure 22. Water vessels
with close-coupled shutoff valves have
a high potential for hydrostatic
pressure buildup on a water
temperature increase. Refer to
applicable codes for relief valve
installation guidelines.
Caution: To prevent shell damage,
install pressure relief valves in the
evaporator water system.
Freeze Protection
If the unit will remain operational at
subfreezing ambient temperatures, the
chilled water system must be protected
from freezing, following the steps listed
below
1. Heat tape is factory-installed on the
packaged unit evaporator and will
protect it from freezing in ambient
temperatures down to -20 F.
2. Install heat tape on all water piping,
pumps, and other components that
may be damaged if exposed to
freezing temperatures. Heat tape
must be designed for low ambient
temperature applications. Heat tape
selection should be based on the
lowest expected ambient
temperature.
3. Add a non-freezing, low temperature,
corrosion inhibiting, heat transfer
fluid to the chilled water system. The
solution must be strong enough to
provide protection against ice
formation at the lowest anticipated
ambient temperature. Refer to Table
1 for evaporator water storage
capacities.
Note: Use of glycol type antifreeze
reduces the cooling capacity of the unit
and must be considered in the design
of the system specifications. 
						

							45RTAA-IOM-3
Domestic Water Heater
Piping
Figure 24 illustrates typical domestic
water heater piping components.
Components and layout will vary
slightly, depending on the location of
connections and the water source. See
unit submittals to insure identification
of water inlet and outlet connections.
Be sure to provide additional vents at
high points in the piping to bleed air
from the water system.
Caution: To prevent damage to
components, do not allow
domestic water heater pressure
(maximum working pressure) to
exceed 150 psig.
Use rubber vibration eliminators to
prevent vibration transmission through
the water lines.
Install a balancing valve in the leaving
water line to control water flow
balance. Install shutoff valves on both
the entering and leaving water lines so
that the domestic water heater can be
isolated for service.
The vent and drain can be used to
temporarily install gauges and
determine pressure drop at the heater.
Water flow rates, as a function of
pressure drop, are charted in Figure 25,
or pressure drop can be calculated
using the following formula:
Pressure Drop (Ft. H20) = 2.31 (Drain
psig -Vent psig)
A pipe strainer should be installed in
the entering water line to prevent
waterborne debris from entering the
domestic water heater.
Domestic Water Heater
Piping Components
“Piping components” include all
devices and controls used to provide
proper water system operation and
unit operating safety. These
components and their general
locations are given below.
Entering Water Piping
[  ] Drain
[  ] Vibration eliminators.
[  ] Shutoff (isolation) valves.
[  ] Pipe strainer.
Caution: To prevent tube damage
install strainer in the water inlet
piping.
Leaving Chilled Water Piping
[  ] Air vents (to bleed air from system)
[  ] Vibration eliminators.
[  ] Shutoff (isolation) valves.
[  ] Balancing valve.
Caution: To prevent damage, do
not exceed 215 psig (14.6 bar)
domestic water heater water
pressure.
Water Pressure Relief Valves
Install a water pressure relief valve in
the outlet piping between the domestic
water  heater and the outlet shutoff
valve, as shown in Figure 24. Water
vessels with close-coupled shutoff
valves have a high potential for
hydrostatic pressure buildup on a
water temperature increase. Refer to
applicable codes for relief valve
installation guidelines.
Caution: To prevent shell damage,
install pressure relief valves in the
evaporator water system.
Freeze Protection
If water in the domestic water heater
will be subjected to subfreezing
ambient temperatures, the water
system must be protected from
freezing, following the steps listed
below:
1. Heat tape is factory-installed on the
domestic water heater and will
protect it from freezing in ambient
temperatures down to -20 F Insure
that electrical power is provided for
the heat tape.
2. Install heat tape on all water piping,
pumps, and other components that
may be damaged if exposed to
freezing temperatures. Heat tape
must be designed for low ambient
temperature applications. Heat tape
selection should be based on the
lowest expected ambient
temperature. 
						

							46RTAA-IOM-3
Figure 24
Typical Domestic Water
Heater Piping
Figure 25
Typical Domestic Water
Heater Piping 
						

							47RTAA-IOM-3
Installation - Mechanical
Remote Evaporator Interconnecting
Refrigerant Piping.
General
The RTAA outdoor unit with the
Remote Evaporator option is shipped
as two pieces: the outdoor unit
(condensing) and the evaporator. The
outdoor unit includes a suction
accumulator line on each circuit and
has the field connections for the
refrigerant at the end opposite the
control panel.
The evaporator is shipped complete
with factory-mounted refrigeration
specialties (electronic expansion
valves, sight-glasses and removable
core filter-dryers). All evaporator
refrigerant line connections are at one
end of the evaporator. The installing
contractor need only provide and
install the refrigerant piping between
the evaporator and the outdoor unit.
System Configuration
The system may be configured in
either of the two primary arrangements
as shown in Figures 26 and 27. The
configuration and its associated
elevation, 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
restrictions:
Figure 26
Remote Evaporator Installation –
No Elevation Difference 
						

							48RTAA-IOM-3
A. The line sizes established in this
installation manual are to be used only
for 40-50 F leaving water temperature
and full-load ice-making applications.
B. The evaporator can be mounted
only on the SAME PLANE OR LOWER
PLANE than the outdoor unit. Figure 28
illustrates what not to do. The elevation
difference is to not exceed 100 feet.C. Piping between evaporator and
outdoor unit is to not exceed 200
(linear) feet or an equivalent length
(includes equivalent length pressure
drop of fittings) of 300 feet.
D. The suction line must never cross or
be above a plane that is 1’8 above the
bottom of the outdoor unit. Figure 29
illustrates what not to do.
Figure 27
Remote Evaporator Installation –
Condenser and Compressor
above Evaporator 
						

							49RTAA-IOM-3
E. Horizontal portions of the suction
lines must be downward sloping to the
compressors. Suction lines must be
insulated.
F. Install an inverted trap in the liquid
line when the evaporator is on a lower
plane than the outdoor unit. The apex
of the trap should be at a height above
the top of the condenser coils. See
Figure 27.
G. Install a suction line trap at the
evaporator when the evaporator is on a
lower plane than the outdoor unit. See
Figure 27.H. The evaporator MUST be matched
with its respective outdoor unit. The
nameplate on the evaporator will have
a serial number that is matched to the
outdoor unit’s serial number. See
Figure 7.
Also the circuits on the outdoor unit
must match the circuits on the
evaporator (I.E. circuit #1 on the
outdoor units must be connected with
circuit #1 on the evaporator).
Caution: If the circuits are crossed,
serious equipment damage may
occur.
See Figure 30 for circuit number
identification.
Figure 28
Restricted Installation –
Evaporator is on a Higher Plane
than the Outdoor Unit
Figure 29 – Restricted Installation -
Suction Line is More Than 1’8
Above Base of Outdoor Unit 
						

							50
RTAA-IOM-3
Figure 30 
Refrigerant Circuit Identification