Specifications

noise-generating condensing units (one condensing unit per fan
coil unit is required in standard split systems).
AN INEXPENSIVE AND CREATIVE SOLUTION TO DESIGN
PROBLEMS — Multi-split duct-free cooling systems are a
matched combination of a 538S outdoor condensing unit and up
to 4 customer-selected indoor fan coil units connected only by re-
frigerant tubing and wires. When combined with the 538S con-
densing unit, the 3 fan coil choices will fit almost any application.
The fan coils can be mounted on the wall, at the ceiling, or in the
ceiling. This selection of fan coils permits inexpensive and cre-
ative solutions to design problems such as:
• add-ons to current space (an office or family room addition)
• special space requirements (a computer room)
• when changes in the cooling load cannot be handled by the
existing system (when adding heat-generating equipment to a
currently conditioned space)
• when adding air conditioning to spaces that are heated by hy-
dronic or electric heat no with ductwork
• historical renovations or any application where preserving the
appearance of the original structure is essential
The compact indoor fan coil units take up very little space in the
room and will not obstruct windows. The fan coils are attrac-
tively styled to blend with most room decors. Advanced system
components incorporate innovative technology to provide reli-
able cooling performance at high efficiencies and low sound
levels.
Duct-free split systems offer the solution of choice. The com-
pressor is located outdoors and is linked by refrigerant lines to
an indoor fan coil located directly in the room it will cool. These
systems have minimal impact on the existing structure, and the
design and interior of the conditioned space is not compromised
by bulky ductwork. Because of these features, duct-free split
systems can be installed in places where conventional ducted
cooling simply cannot go.
LOW SOUND LEVELS — Minimal sound levels are synony-
mous with the multi-split system. When noise is a concern, the
multi-split duct-free cooling system is the answer because you
don’t have to worry about duct design or the inherent noise as-
sociated with ducted systems. There are no compressors in-
doors, either in the conditioned space or directly over it. The
indoor units are whisper quiet. The outdoor units operate at
sound levels as low as 6.8 bels, and are the perfect answer to
sound level ordinances.
When sound ordinances and proximity to neighbors demand
ultraquiet operation, the 538S is the right choice: The advanced,
horizontal airflow design distributes air more evenly over the
coil. This design reduces local air velocity and a potential source
of noise.
HIGH EFFICIENCY — With SEERs (seasonal energy efficiency
ratios) of 12.0, the duct-free split systems save energy and may
qualify for utility company rebates in some areas.
SECURE OPERATION — If security is an issue, outdoor and in-
door units are connected only by refrigerant piping and wiring to
prevent intruders from crawling through ductwork. In addition,
since 538S units can be installed 6 in. away from outside walls,
coils are protected from vandals and severe weather.
FAST INSTALLATION — These compact multi-split systems
take only a few hours to install, since only wire and piping need
to be connected. The fast and easy installation ensures minimal
disruption to customers in the home or workplace. This is an
added advantage of Carrier’s multi-split systems, especially in
retrofit situations.
SIMPLE SERVICING AND MAINTENANCE — Removing a
single panel on outdoor units provides immediate access to the
isolated compressor and control compartment, allowing a serv-
ice technician access to check unit operation without a loss of
condenser airflow. In addition, the blow-thru design of the out-
door section means that dirt accumulates on the inside surface
of the coil. Coils can be cleaned quickly from the outside using
a pressure hose and detergent without removing grilles or using
fin combs.
The outdoor units also include a microprocessor-based control
board that features expanded diagnostics through multiple LED
(light-emitting diode) displays.
On indoor units, service and maintenance expense is reduced
due to easy-to-change cleanable filters on all units. In addition,
the high wall systems have extensive self-diagnostics to assist
in troubleshooting. All units have easy-access coils and clean-
able condensate pans to assist in meeting indoor air quality
standards.
All refrigerant service valves are brass, front-seating type with
sweat connections. The valves are externally located so refrig-
erant tube connections can be made quickly and easily. Each
suction valve has a service port for ease of checking operating
refrigerant pressures. Internal service ports are also provided to
make servicing even easier.
BUILT-IN RELIABILITY — These multi-split system indoor and
outdoor units are designed to provide years of trouble-free
operation.
The high wall indoor units include freeze-up protection, high
temperature protection, and self diagnostics. Other indoor units
are protected by outdoor unit controls and have limited diagnos-
tics available through standard or accessory 24-v thermostats.
The 538S condensing units are the only dedicated commercial
units with all safety features standard to ensure high perfor-
mance and lasting reliability under the most demanding condi-
tions. For example, an accumulator safeguards the compressor
against loss of lubrication, while capacitors assure dependable
start-ups, especially during low voltage conditions (down to
187 v). High- and low-pressure safety switches, liquid line filter
drier, and lock-out protection are standard.
NOTE: Compressor start-up delay through the controller is
standard for 619C,E,F units.
The 538S unit also has a fan-cycling head pressure control sys-
tem as a standard feature, which permits cooling operation
down to −20 F (wind baffles and a winter start kit are also
recommended).
The totally-enclosed condenser-fan motor means greater reli-
ability under rainy conditions, ensuring dependable perfor-
mance for many years.
INDIVIDUAL ROOM ZONING FOR OPTIMAL COMFORT —
Maximum comfort is provided because each space can have in-
dividual set points and can be controlled based on actual usage.
The air sweep feature provided on high wall and ceiling-
suspended systems permits optimal room air mixing to elimi-
nate hot and cold spots to enhance occupant comfort.
In addition, year-round comfort may be provided by combining
standard cooling outdoor units with heat pump versions of some
fan coil units. This combination can provide electric resistance
heating capability.
ECONOMICAL OPERATION — The duct-free split system de-
sign allows individual room cooling only where required. There
is no need to run large supply-air fans or chilled water pumps to
handle a few spaces with unique load patterns. In addition, be-
cause air is moved only in the space required, no energy is
wasted moving air through ducts.
Features like the permanent split-capacitor type motors provide
more economical operation, and the rifled copper tube with lou-
vered aluminum plate fin coils provide maximum heat transfer.
LIGHTWEIGHT, COMPACT SIZE —The small footprint of the
538S units provides additional benefits. Exclusive aeroacous-
tics make these units the most compact in the industry. Because
they require minimal service and airflow clearances, condens-
ing units can be located virtually anywhere — on the ground,
roof, balcony, or under a deck.
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