5167798-YTG-J-0218
12
Johnson Controls Unitary Products
shall be CSA certified to ANSI Z21.47 and UL 1995/CAN/CSA No.
236-M90 standards.
UNIT CABINET
Unit cabinet shall be constructed of galvanized steel with
exterior surfaces coated with a non-chalking, powder paint
finish, certified at 1000 hour salt spray test per ASTM-B117
standards. Indoor blower sections shall be insulated with up to
1” thick insulation coated on the airside. Either aluminum foil
faced or elastometric rubber insulation shall be used in the
unit’s compartments and be fastened to prevent insulation from
entering the air stream. Cabinet doors shall be hinged with
toolless access for easy servicing and maintenance. Full
perimeter base rails shall be provided to assure reliable transit
of equipment, overhead rigging, fork truck access and proper
sealing on roof curb applications. Disposable 2” filters shall be
furnished as standard and be accessible through hinged access
door. Fan performance measuring ports shall be provided on
the outside of the cabinet to allow accurate air measurements
of evaporator fan performance without removing panels or
creating bypass of the coils. Condensate pan shall be slide out
design, constructed of a non corrosive material, internally
sloped and conforming to ASHRAE 62-B9 standards.
Condensate connection shall be a minimum of ¾” I.D. female
and be rigid mount connection.
INDOOR (EVAPORATOR) FAN ASSEMBLY
Fan shall be a belt drive assembly and include an adjustable
pitch motor pulley. Job site selected brake horsepower shall not
exceed the motors nameplate horsepower rating plus the ser-
vice factor. Units shall be designed to operate within the service
factor. Fan wheel shall be double inlet type with forward curve
blades, dynamically balanced to operate smoothly throughout
the entire range of operation. Airflow design shall be constant
volume. Bearings shall be sealed and permanently lubricated
for longer life and no maintenance. Entire blower assembly and
motor shall be slide out design.
OUTDOOR (CONDENSER) FAN ASSEMBLY
The outdoor fans shall be of the direct drive type, discharge air
vertically, have aluminum blades riveted to corrosion resistant
steel spider brackets and shall be dynamically balanced for
smooth operation. The outdoor fan motors shall have permanently
lubricated bearings internally protected against overload
conditions and staged independently. A cleaning window shall be
provided on two sides of the units for coil cleaning.
REFRIGERANT COMPONENTS
Compressors:
a. Shall be fully hermetic type, direct drive, internally
protected with internal high-pressure relief and over
temperature protection. The hermetic motor shall be
suction gas cooled and have a voltage range of + or –
10% of the unit nameplate voltage.
b. Shall have internal spring isolation and sound muffling to
minimize vibration and noise, and be externally isolated
on a dedicated, independent mounting.
Coils:
a. Evaporator coils shall have aluminum plate fins
mechanically bonded to seamless internally enhanced
copper tubes with all joints brazed. Special Phenolic
coating shall be available as a factory option.
b. Evaporator coils shall be of the direct expansion, draw-
thru design.
c. Condenser coils shall have Mirco-Channel aluminum
tube, aluminum fins.
d. Condenser coils shall be of the direct expansion, draw-
thru design.
Refrigerant Circuit and Refrigerant Safety Components shall
include:
a. Independent fixed-orifice or thermally operated
expansion devices.
b. Solid core filter drier/strainer to eliminate any moisture or
foreign matter.
c. Accessible service gage connections on both suction
and discharge lines to charge, evacuate, and measure
refrigerant pressure during any necessary servicing or
troubleshooting, without losing charge.
d. The unit shall have two independent refrigerant circuits,
equally split in 50% capacity increments.
Unit Controls:
a. Unit shall be complete with self-contained low-voltage
control circuit protected by a resettable circuit breaker on
the 24-volt transformer side.
b. Unit shall incorporate a lockout circuit which provides
reset capability at the space thermostat or base unit,
should any of the following standard safety devices trip
and shut off compressor.
1. Loss-of-charge/Low-pressure switch.
2. High-pressure switch.
3. Freeze condition sensor on evaporator coil. If any of
these safety devices trip, the LCD screen will display
the alarm message.
c. Unit shall incorporate "AUTO RESET" compressor over
temperature, over current protection.
d. Unit shall operate with conventional thermostat designs
and have a low voltage terminal strip for easy hook-up.
e. Unit control board shall have on-board diagnostics and
fault message display.
f. Standard controls shall include anti-short cycle and low
voltage protection, and permit cooling operation down to
a selectable value as low as 0 °F.
g. Control board shall monitor each refrigerant safety switch
independently.
GAS HEATING SECTION (IF EQUIPPED)
Heat exchanger and exhaust system shall be constructed of
aluminized steel and shall be designed with induced draft com-