Carrier GEMINI SELECT 38APS025-065 Product Data page 93

Some of the diagnostics that are included are:
• Monitoring of all sensors
• Suction and discharge pressure transducers to provide
compressor protection and coil freeze protection
• Monitoring of compressor status using compressor pro-
tection boards
• Compressor lockout at low ambient conditions
• Low refrigerant charge protection
• Compressor reverse rotation protection
• Low superheat protection
Control interface
The ComfortLink controller can interface with the Carrier
Comfort Network devices through the 485 communica-
tions port. This will allow for the use of all system control
programs. These include:
• Network Service Tool
• Touch Pilot™ device
• ComfortVIEW™ software
• CCN Web software
The control can also provide interface with non-Carrier
energy management systems with the addition of either
the BACnet/MODBUS Carrier translator or the Lon-
Works Carrier translator. Several contact connection
points have been provided in the main control box for in-
terface to external controls and systems.
Constant volume applications — The units can be
configured to operate in CV applications. The unit operate
with either a standard (mechanical or electronic) 2-stage
cool thermostat, or with an electronic room temperature
sensor and a timeclock to establish unit start and stop
times. With a standard thermostat (programmable is op-
tional), cooling operation is set by space temperature. With
a space sensor and field-supplied timeclock, the machine
will operate at default values unless they are changed using
appropriate input devices.
Features with thermostat control of unit include:
• Two-stage cooling or adaptive multiple stage cooling
which can provide 2 to 6 stages of capacity when sup-
ply air sensors installed. Refer to Loading Sequences
tables in the Application Data section on page 99 for
specific capacity control.
• Control of unit using Y1, Y2 thermostat or T55, T56,
or T58 space sensors.
• Control of a condenser fan based on outdoor-air and
condensing pressures.
• Compressor time guard override (power up and mini-
mum on and off timers) to assure air return in low load
conditions.
Features with sensor control (three options available) of
unit include:
• T55 sensor will monitor room temperature and provide
unoccupied override capability (1 to 4 hours).
• T56 sensor will monitor room temperature, provide
unoccupied override capability (1 to 4 hours), and pro-
vide a temperature offset of 5° F (2.7° C) maximum.
• T58 is a CCN communicating sensor that will provide
the set point and space temperature values.
Standard features include:
• Two-stage cooling or adaptive multiple stage cooling
which can provide 2 to 6 stages of capacity when sup-
ply air sensors installed. Refer to Loading Sequences
tables in the Application Data section on page 99 for
specific capacity control.
• Adjustment of space temperature set points of ± 5° F
(2.7° C) when using a T56 sensor.
• 365-day timeclock with backup (supports minute, hour,
and day of week, date, month, and year access). The
timeclock includes the following features:
- Daylight savings time function
- Occupancy control with 8 periods for unit operation
- Holiday table containing up to 18 holiday schedules
• Ability to initiate timed override from T55 or T56 sen-
sors (for a timed period of 1 to 4 hours).
• For units connected into a CCN network the timeclock
can be integrated into the overall building energy man-
agement system and be updated remotely.
Variable air volume (VAV) applications — Units
are configured to operate in VAV applications are designed
to control the leaving-air temperature in cooling to a con-
figurable set point. Some of the features for VAV units in a
stand-alone application include:
• The units are shipped as operable, stand-alone units
with the addition of a field-supplied timeclock to
establish unit start and stop times or they can use
ComfortLink™ time of day scheduling routine.
• Provide cooling control.
• Supports an optional space temperature sensor for
mode control and supply air temperature reset.
• If space sensor is equipped with an override feature, the
sensor will allow operation during the unoccupied
period for a fixed length of time.
• Control board diagnostics.
• Control of an outdoor-air fan based upon outdoor-air
temperature and saturated condensing temperature.
• Support of remote occupied/unoccupied input to start.
• Support a field test for field check out.
• Cooling capacity control of 2 to 6 stages plus econo-
mizer. Refer to Loading Sequences tables in the Appli-
cation Data section on page 99 for specific capacity
control.
• Compressor time delays to prevent rapid cycling of
compressors.
• Automatic lead-lag control of compressors to reduce the
number of compressor cycles.
• With the addition of the energy management board, the
ComfortLink™ controls will also support demand limit-
ing and remote set point control.
When the unit is connected to a CCN (Carrier Comfort
®
Network ) system, the following additional features can be
used:
• Interface of the unit clock with the CCN network clock
and allow for remote configuration of the schedules.
• CCN demand limit participation.
that
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