Specifications

FEATURES/BENEFITS (cont)
LOW SOUND LEVELS — When noise is a concern, the duct-
free split systems are the answer because you do not have
to worry about duct design. There are no compressors indoors,
either in the conditioned space or directly over it, and there is
none of the noise usually generated by air being forced through
ductwork. These indoor units are whisper quiet. The outdoor
units operate at sound levels as low as 65 decibels, and are the
perfect answer to sound level ordinances.
When sound ordinances and proximity to neighbors demand
ultra-quiet operation, the 538B and 538D are the right choice:
The advanced, horizontal airflow design distributes air more
evenly over the coil. On the 538B unit and 538D018 and 024
units, the coil acts as an extra sound-muffling device before the
air is discharged at a very low velocity.
HIGH EFFICIENCY — With SEERs (seasonal energy efficiency
ratios) up to 11.5 and HSPFs (heating seasonal performance
factors) up to 7.6, these 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 538B units can be installed 6 in. away from outside walls,
coils are protected from vandals and severe weather.
FAST INSTALLATION — These compact duct-free split sys-
tems take just a few hours to install, since only wire and piping
need to be run. The fast and easy installation permits minimal
disruption to customers in the home or workplace. This is an
added advantage of these duct-free split systems, especially in
retrofit situations.
Features like mounting brackets and templates make the unit
very easy to install. In fact, the ceiling-suspended units are even
furnished with indoor-to-outdoor connecting cables.
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, on 538B units, the blow-thru de-
sign of the outdoor 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.
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.
Both refrigerant service valves are brass, back-seating type with
sweat (538B and 538D018,024) or flare (538D009,012) connec-
tions. The valves are externally located so refrigerant tube con-
nections can be made quickly and easily. Each valve has a
service port for ease of checking operating refrigerant pressures
(538B and 538D018,024 units).
Internal service ports (538B and 538D018,024) are also pro-
vided to make servicing even easier, and the heating refrigerant
metering device is conveniently located in the liquid-line service
valve (538B and 538D018,024 only).
BUILT-IN RELIABILITY — These duct-free 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 24v thermostats.
The 538B and 538D018,024 outdoor units are the only dedi-
cated commercial units with all safety features standard to en-
sure high performance and lasting reliability under the most
demanding situations. For example, an accumulator safeguards
the compressor against loss of lubrication, while start capacitors
and relays (non-scroll units) assure dependable start-ups, espe-
cially during low voltage conditions down to 187 v. High- and
low-pressure safety switches, crankcase heater (non-scroll
units), bi-flow liquid line filter drier, and lockout protection are
standard on most sizes and Time GuardT compressor protec-
tion can be included.
NOTE: Time delay compressor protection is provided by the
microprocessor or 24v thermostat when outdoor unit is matched
with 619C or 619F fan coil units.
The totally-enclosed outdoor-fan motor means greater reliability
under rain conditions, ensuring dependable performance for
many years.
INDIVIDUAL ROOM COMFORT — Maximum comfort is pro-
vided because each space can have individual set points and
may be controlled based on actual usage. The air sweep feature
provided on high wall and ceiling-suspended systems permits
optimal room air mixing to eliminate hot and cold spots and en-
hance occupant comfort.
Heat pumps with booster heat mode (cassette and ceiling sus-
pended units) provide even greater comfort in heat pump opera-
tion. With the high wall unit, warm-start features mean
occupants are never subjected to cold drafts on start-up or
defrost.
ECONOMICAL OPERATION — The duct-free split system de-
sign allows individual room cooling and heating only where re-
quired. 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, because 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 coil provides maximum heat transfer.
When demand defrost is used with high wall units, only the mini-
mum amount of energy is used to defrost the coil. In addition,
the blow-thru design of the 538B units results in even lower en-
ergy usage in defrost mode.
TABLE OF CONTENTS
Page
Features/Benefits ............................... 1-4
Model Number Nomenclature ..................... 5,6
ARI Capacities ................................. 6
Accessories ................................... 7-10
Physical Data ..................................11-17
Base Unit Dimensions ...........................18-24
Selection Procedure ............................. 25
Performance Data ..............................26-58
Electrical Data ................................. 59
Typical Piping and Wiring ........................60-63
Application Data ................................64-71
Typical Wiring Schematics ........................72-76
Controls ......................................77-81
Guide Specifications ............................82-87
2