Smoke Control Modes; Fire-Smoke Inputs; Indoor Air Quality Control - Carrier 48AJ Operating And Service Manual

Smoke Control Modes —
trol modes that can be used to control smoke within areas ser-
viced by the unit: Pressurization mode, Evacuation mode,
Smoke Purge mode, and Fire Shutdown. Evacuation, Pressur-
ization and Smoke Purge modes require the Controls Expan-
sion Board (CEM). The Fire Shutdown input is located on the
main board (MBB) on terminals TB5-10 and 11. The unit may
also be equipped with a factory-installed return air smoke de-
tector that is wired to TB5-10 and 11 and will shut the unit
down if a smoke condition is determined. Field-monitoring
wiring can be connected to terminal TB5-8 and 9 to monitor
the smoke detector. Inputs on the CEM board can be used to
put the unit in the Pressurization, Evacuation, and Smoke
Purge modes. These switches or inputs are connected to TB6 as
shown below. Refer to Major System Components section on
page 94 for wiring diagrams.
Pressurization — TB6-12 and 13
Evacuation — TB6-13 and 14
Smoke Purge — TB6-13 and 15
Each mode must be energized individually on discrete in-
puts and the corresponding alarm is initiated when a mode is
activated. The fire system provides a normally closed dry con-
tact closure. Multiple smoke control inputs, sensed by the con-
trol will force the unit into a Fire Shutdown mode.
FIRE-SMOKE INPUTS — These discrete inputs can be
found on the local display under Inputs
ITEM EXPANSION
FIRE

FIRE-SMOKE INPUTS

FSD Fire Shutdown Input
PRES Pressurization Input
EVAC Evacuation Input
PURG Smoke Purge Input
Fire Shutdown Mode — This mode will cause an immediate
and complete shutdown of the unit.
Pressurization Mode — This mode attempts to raise the pres-
sure of a space to prevent smoke infiltration from an adjacent
space. Opening the economizer (thereby closing the return air
damper), shutting down power exhaust and turning the indoor
fan on will increase pressure in the space.
Evacuation Mode — This mode attempts to lower the pres-
sure of the space to prevent infiltrating an adjacent space with
its smoke. Closing the economizer (thereby opening the return-
air damper), turning on the power exhaust and shutting down
the indoor fan decrease pressure in the space.
Smoke Purge Mode — This mode attempts to draw out
smoke from the space after the emergency condition. Opening
the economizer (thereby closing the return-air damper), turning
on both the power exhaust and indoor fan will evacuate smoke
and bring in fresh air.
AIRFLOW CONTROL DURING THE FIRE-SMOKE
MODES — All non-smoke related control outputs will get
shut down in the fire-smoke modes. Those related to airflow
will be controlled as explained below. The following matrix
specifies all actions the control shall undertake when each
mode occurs (outputs are forced internally with CCN priority
number 1 - "Fire"):
DEVICE PRESSURIZATION PURGE EVACUATION
Economizer 100%
Indoor Fan —
ON/FSO*
VFD
Power Exhaust OFF
Heat Interlock
ON
Relay
*"FSO" refers to the supply VFD fire speed override configurable
speed.
There are four smoke con-
→
FIRE.
CCN WRITE
RANGE
POINT STATUS
ALRM/NORM FSD forcible
ALRM/NORM PRES forcible
ALRM/NORM EVAC forcible
ALRM/NORM PURG forcible
FIRE
SHUTDOWN
100% 0% 0%
ON/FSO* OFF OFF
ON ON OFF
ON OFF OFF
RELEVANT ITEMS:
The economizer's commanded output can be found in
→ →
Outputs ECON ECN.C.
The configurable fire speed override for supply fan VFD is in
→ →
Configuration SP
The supply fan relay's commanded output can be found in
→ →
Outputs FANS S.FAN.
The supply fan VFD's commanded speed can be found in
→ →
Outputs FANS S.VFD.
Indoor Air Quality Control —
(IAQ) function will admit fresh air into the space whenever
space air quality sensors detect high levels of CO
When a space or return air CO
unit control, the unit's IAQ routine allows a demand-based
control for ventilation air quantity, by providing a modulating
outside air damper position that is proportional to CO
The ventilation damper position is varied between a minimum
ventilation level (based on internal sources of contaminants
and CO levels other than from the effect of people) and the
2
maximum design ventilation level (determined at maximum
populated status in the building). Demand Control Ventilation
(DCV) is also available when the ComfortLink™ unit is con-
nected to a CCN system using ComfortID™ terminal controls.
This function also provides alternative control methods for
controlling the amount of ventilation air being admitted,
including fixed outdoor air ventilation rates (measured as cfm),
external discrete sensor switch input and externally generated
proportional signal controls.
The IAQ function requires the installation of the factory-
option economizer system. The DCV sequences also require
the connection of accessory (or field-supplied) space or return
air CO sensors. Fixed cfm rate control requires the factory-
2
installed outdoor air cfm option. External control of the
ventilation position requires supplemental devices, including a
4 to 20 mA signal, a 10-k ohm potentiometer, or a discrete
switch input, depending on the method selected. Outside air
CO levels may also be monitored directly and high CO
2
economizer restriction applied when an outdoor air CO
is connected. (The outdoor CO
installation of the Controls Expansion Module [CEM].)
The ComfortLink control has the capability of DCV using
an IAQ sensor. The indoor air quality (IAQ) is measured using
a CO sensor whose measurements are displayed in parts per
2
million (ppm). The IAQ sensor can be field-installed in the
return duct. There is also an accessory space IAQ sensor that
can be installed directly in the occupied space. The sensor must
provide a 4 to 20 mA output signal and must include its own
24-v supply. The sensor connects to terminal TB5-6 and 7. Be
sure to leave the 182-ohm resistor in place on terminals 6 and 7.
OPERATION — The unit's indoor air quality algorithm mod-
ulates the position of the economizer damper between two user
configurations depending upon the relationship between the
IAQ and the outdoor air quality (OAQ). Both of these values
can be read at the Inputs
two configurable positions is referred to as the IAQ Demand
Vent Min Position (IAQ.M), while the higher is referred to as
Economizer Minimum Position (EC.MN). The IAQ.M should
be set to an economizer position that brings in enough fresh air
to remove contaminants and CO
than people. The EC.MN value should be set to an economizer
position that brings in enough fresh air to remove contaminants
and CO generated by all sources including people. The
2
EC.MN value is the design value for maximum occupancy.
63
SP.FS.
The indoor air quality
.
2
sensor is connected to the
2
sensor connection requires
2
→
AIR.Q submenu. The lower of these
generated by sources other
2
level.
2
2
sensor
2