Bryant Legacy Line Series Manual page 52

GUIDE SPECIFICATIONS (CONT)
g. Economizer controller on EconoMi$er IV mod-
els shall be Honeywell W7212 that provides:
1) Combined minimum and DCV maximum
damper position potentiometers with com-
pressor staging relay.
2) Functions with solid state analog enthalpy
or dry bulb changeover control sensing.
3) Contain LED indicates for:
when free cooling is available, when mod-
ule is in DCV mode, when exhaust fan con-
tact is closed.
h. Economizer controller on EconoMi$er X models
shall be the Honeywell W7220 that provides:
1) 2-line LCD interface screen for setup, con-
figuration and troubleshooting.
2) On-board Fault Detection and Diagnostics
(FDD) that senses and alerts when the
economizer is not operating properly, per
California Title 24.
3) Sensor failure loss of communication iden-
tification.
4) Automatic sensor detection
5) Capabilities for use with multiple-speed
indoor fan systems.
6) Utilize digital sensors: Dry bulb and
Enthalpy.
i. Economizer controller on EconoMi$er 2 models
with RTU Open models shall be a 4-20mA
design controlled directly by the RTU Open con-
troller. RTU Open meets California Title 24 Fault
Detection and Diagnostic (FDD) requirements.
j. Shall be capable of introducing up to 100% out-
door air.
k. Shall be equipped with a barometric relief
damper capable of relieving up to 100% return
air and contain seals that meet ASHRAE 90.1
requirements.
l. Shall be designed to close damper(s) during
loss-of-power situations with spring return built
into motor.
m. Dry bulb outdoor air temperature sensor shall be
provided as standard. Enthalpy sensor is also
available on factory installed only. Outdoor air
sensor setpoint shall be adjustable and shall range
from 40°F to 100°F /4°C to 38°C. Additional sen-
sor options shall be available as accessories.
n. The economizer controller shall also provide
control of an accessory power exhaust unit
function. Factory set at 100%, with a range of
0% to 100%.
o. The economizer shall maintain minimum air-
flow into the building during occupied period
and provide design ventilation rate for full
occupancy.
p. Dampers shall be completely closed when the
unit is in the unoccupied mode.
q. Economizer controller shall accept a 2 to 10 vdc
CO sensor input for IAQ/DCV control. In this
2
mode, dampers shall modulate the outdoor air
52
damper to provide ventilation based on the sen-
sor input.
r. Compressor lockout temperature on W7220 is
adjustable from –45°F to 80°F, set at a factory
default of 32°F. Others shall open at 35°F (2°C)
and closes at 50°F (10°C).
s. Actuator shall be direct coupled to economizer
gear. No linkage arms or control rods shall be
acceptable.
t. Economizer controller shall provide indications
when in free cooling mode, in the DCV mode,
or the exhaust fan contact is closed.
2. Integrated EconoMi$er2, and EconoMi$er X Ultra
Low Leak rate models. (Factory installed on
3 phase models only. Field installed on all 3 and
1 phase models)
a. Integrated, gear driven opposing modulating
blade design type capable of simultaneous
economizer and compressor operation.
b. Independent modules for vertical or horizontal
return configuration shall be available. Vertical
return modules shall be available as a factory-
installed option.
c. Damper blades shall be galvanized steel with
composite gears. Plastic or composite blades on
intake or return shall not be acceptable.
d. Shall include all hardware and controls to pro-
vide free cooling with outdoor air when tem-
perature and/or humidity are below set points.
e. Shall be equipped with gear driven dampers for
both the outdoor ventilation air and the return
air for positive air stream control.
f. Ultra Low Leak design meets California Title
24 section 140.4 and ASHRAE 90.1 require-
ments for 4 cfm per sq.ft. on the outside air
dampers and 10 cfm per sq. ft. on the return
dampers.
g. Economizer controller on EconoMi$er X models
shall be the Honeywell W7220 that provides:
1) 2-line LCD interface screen for setup, con-
figuration and troubleshooting.
2) On-board Fault Detection and Diagnostics
(FDD) that senses and alerts when the
economizer is not operating properly, per
California Title 24.
3) Sensor failure loss of communication iden-
tification.
4) Automatic sensor detection.
5) Capabilities for use with multiple-speed
indoor fan systems.
6) Utilize digital sensors: Dry bulb and
Enthalpy.
h. Economizer controller on EconoMi$er 2 mod-
els with RTU Open models shall be a 4 to
20mA design controlled directly by the RTU
Open controller. RTU Open meets California
Title 24 Fault Detection and Diagnostic (FDD)
requirements.