246699-YTG-D-1208
44
Johnson Controls Unitary Products
Refrigerant Circuit and Refrigerant Safety Components shall
include:
A. Independent fixed-orifice or thermally operated expan-
sion 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:
C. Loss-of-charge/Low-pressure switch.
(1) High-pressure switch.
(2) Freeze-protection thermostat, evaporator coil. If any
of the above safety devices trip, an LED (light-emitting
diode) indicator shall flash a diagnostic code that indi-
cates which safety switch has tripped.
D. Unit shall incorporate “AUTO RESET” compressor over
temperature, over current protection.
E. Unit shall operate with conventional thermostat designs
and have a low voltage terminal strip for easy hook-up.
F.
Unit control board shall have on-board diagnostics and
fault code display.
G. Standard controls shall include anti-short cycle and low
voltage protection, and permit cooling operation down to
0 ºF.
H. Control board shall monitor each refrigerant safety
switch independently.
I.
Control board shall retain last 5 fault codes in non-vola-
tile memory, which will not be lost in the event of a power
loss.
GAS HEATING SECTION (IF EQUIPPED)
Heat exchanger and exhaust system shall be constructed of
aluminized steel and shall be designed with induced draft
combustion with post purge logic, energy saving direct spark
ignition, and redundant main gas valve. The heat exchanger
shall be of the tubular type, constructed of T1-40 aluminized
steel for corrosion resistance and allowing minimum mixed
air entering temperature of 40 ºF. Burners shall be of the in-
shot type, constructed of aluminum-coated steel. All gas pip-
ing shall enter the unit cabinet at a single location, through
either the side or bottom, without any field modifications. An
integrated control board shall provide timed control of evapo-
rator fan functioning and burner ignition. Heating section shall
be provided with the following minimum protection:
A. Primary and auxiliary high-temperature limit switches.
B. Induced draft pressure sensor.
C. Flame roll out switch (manual reset).
D. Flame proving controls. Unit shall have two independent
stages of capacity (60% 1
st
stage, 100% 2
nd
stage).
ELECTRIC HEATING SECTION (IF EQUIPPED)
An electric heating section, with nickel chromium elements,
shall be provided in a range of 9 thru 54 KW, offering two
states of capacity all sizes. The heating section shall have a
primary limit control(s) (automatic reset) to prevent the heat-
ing element system from operating at an excessive tempera-
ture. The Heating Section assembly shall slide out of the unit
for easy maintenance and service. Units with Electric Heating
Sections shall be wired for a single point power supply with
branch circuit fusing (where required).
UNIT OPERATING CHARACTERISTICS
Unit shall be capable of starting and running at 125 ºF out-
door temperature, exceeding maximum load criteria of ARI
Standard 340/360. The compressor, with standard controls,
shall be capable of operation down to 0 ºF outdoor tempera-
ture. Unit shall be provided with fan time delay to prevent cold
air delivery before heat exchanger warms up. (Gas heat only)
ELECTRICAL REQUIREMENTS -
All unit power wiring shall
enter unit cabinet at a single factory provided location and be
capable of side or bottom entry to minimize roof penetrations
and avoid unit field modifications. Separate side and bottom
openings shall be provided for the control wiring.
STANDARD LIMITED WARRANTIES
-
Compressor - 5
Years, Heat Exchanger - 10 Years, Elect. Heat Elem. - 5
Years, Parts - 1 Year
FACTORY INSTALLED OPTIONAL OUTDOOR AIR
(Shall
be made available by either/or):
1.
ELECTRONIC ENTHALPY AUTOMATIC ECONO-
MIZER
- Outdoor and return air dampers that are inter-
locked and positioned by a fully-modulating, spring-
return damper actuator. The maximum leakage rate for
the outdoor air intake dampers shall not exceed 2%
when dampers are fully closed and operating against a
pressure differential of 0.5 IWG. A unit-mounted potenti-
ometer shall be provided to adjust the outdoor and return
air damper assembly to take in outdoor air to meet the
minimum ventilation requirement of the conditioned
space during normal operation. During economizer oper-
ation, a mixed-air temperature control shall modulate the
