Bryant Legacy Line Series Manual page 53

i. Shall be capable of introducing up to 100% out-
door air.
j. Shall be equipped with a barometric relief
damper capable of relieving up to 100% return
air and contain seals that meet ASHRAE 90.1
requirements.
k. Shall be designed to close damper(s) during
loss-of-power situations with spring return built
into motor.
l. Dry bulb outdoor air temperature sensor shall be
provided as standard. Enthalpy sensor is also
available on factory installed only. Outdoor air
sensor setpoint shall be adjustable and shall range
from 40°F to 100°F / 4°C to 38°C. Additional sen-
sor options shall be available as accessories.
m. The economizer controller shall also provide
control of an accessory power exhaust unit
function. Factory set at 100%, with a range of
0% to 100%.
n. The economizer shall maintain minimum air-
flow into the building during occupied period
and provide design ventilation rate for full
occupancy.
o. Dampers shall be completely closed when the
unit is in the unoccupied mode.
p. Economizer controller shall accept a 2-10 vdc
CO sensor input for IAQ/DCV control. In this
2
mode, dampers shall modulate the outdoor air
damper to provide ventilation based on the sen-
sor input.
q. Compressor lockout temperature on W7220 is
adjustable from –45°F to 80°F, set at a factory
default of 32°F. Others shall open at 35°F (2°C)
and closes at 50°F (10°C).
r. Actuator shall be direct coupled to economizer
gear. No linkage arms or control rods shall be
acceptable.
s. Economizer controller shall provide indications
when in free cooling mode, in the DCV mode,
or the exhaust fan contact is closed.
3. Two-Position Damper
3 Phase Models Only. Field-installed on all 3 and
1 Phase Models)
a. Damper shall be a Two-Position Damper.
Damper travel shall be from the full closed
position to the field-adjustable percent-open set
point.
b. Damper shall include adjustable damper travel
from 25% to 100% (full open).
c. Damper shall include single or dual blade, gear
driven dampers and actuator motor.
d. Actuator shall be direct coupled to damper gear.
No linkage arms or control rods shall be
acceptable.
e. Damper will admit up to 100% outdoor air for
applicable rooftop units.
f. Damper shall close upon indoor (evaporator)
fan shutoff and/or loss of power.
(Factory-installed on
g. The damper actuator shall plug into the rooftop
unit's wiring harness plug. No hard wiring shall
be required.
h. Outside air hood shall include aluminum water
entrainment filter.
4. Manual damper
a. Manual damper package shall consist of
damper, air inlet screen, and rain hood which
can be preset to admit up to 25% or 50% out-
door air for year-round ventilation.
5. Perfect Humidity ™
(3 Phase Models Only):
a. The Perfect Humidity Dehumidification System
shall be factory installed and shall provide
greater dehumidification of the occupied space
by two modes of dehumidification operations in
addition to its normal design cooling mode:
1) Subcooling mode further subcools the hot
liquid refrigerant leaving the condenser coil
when both temperature and humidity in the
space are not satisfied.
2) Hot gas reheat mode shall mix a portion of
the hot gas from the discharge of the com-
pressor with the hot liquid refrigerant leav-
ing the condenser coil to create a two-phase
heat transfer in the system, resulting in a
neutral leaving air temperature when only
humidity in the space is not satisfied.
3) Includes head pressure controller.
6. Head Pressure Control Package
a. Controller shall control coil head pressure by
condenser fan speed modulation or condenser
fan cycling and wind baffles.
b. Shall consist of solid-state control and con-
denser coil temperature sensor to maintain con-
densing temperature between 90°F (32°C) and
110°F (43°C) at outdoor ambient temperatures
down to –20°F (–29°C).
7. Propane Conversion Kit
a. Package shall contain all the necessary hard-
ware and instructions to convert a standard nat-
ural gas unit for use with liquefied propane, up
to 2000 ft (610m) elevation.
b. Additional accessory kits may be required for
applications above 2000 ft (610m) elevation.
8. Flue Shield
a. Flue shield shall provide protection from the hot
sides of the gas flue hood.
9. Condenser Coil Hail Guard Assembly (Factory-
installed on 3 Phase Models Only. Field-installed
on all 3 and 1 Phase Models)
a. Shall protect against damage from hail.
b. Shall be either hood style or louvered.
Dehumidification System
53