Specifications

SMOKE DETECTOR
A smoke detector can be used to initiate fire shutdown.
This can be accomplished by a set of normally closed pilot
relay contacts which will interrupt power from the 24-v trans-
former, secondary ‘‘B’’ terminal to the control circuit breaker
(CB4). The wire that connects these two points is white and
labeled ‘‘W78.’’
NOTE: On standard gas models, the indoor fan will con-
tinue to run 45 seconds after the call for heat has been
terminated. If fire shutdown is initiated the fan will stop
immediately. No 45-second delay will occur.
The smoke detector may be mounted in the return-air
duct or the supply duct. Carrier does not make recommen-
dations as to specific smoke detector location due to liability
considerations.
IAQ CONTROL
The accessory expansion board and accessory IAQ (in-
door air quality) sensor are required for IAQ control. The
Carrier sensors operate witha4to20mAsignal. The 4 to
20 mA signal is connected to T11 (+) and T12 (−) on the
expansion board for the IAQ sensor, and T13 (+) and T14
(−) on the expansion board for the OAQ (outdoor air qual-
ity) sensor. The sensor is field-mounted and wired to the
expansion board installed in the unit main control box. The
IAQ sensor must be powered by a field-supplied 24-v power
supply (ungrounded). Do not use the unit 24-v power supply
to power the sensor.
Once installed, the sensor must be enabled via unit soft-
ware access. The sensor is configured with default values
which may be changed through network access software. To
work properly, the IAQ sensor high and low reference points
for the sensor that is used must match the configured values.
The expansion board reacts toa4to20mAsignal from the
IAQ sensor. The low reference (4 mA output) must be con-
figured to the minimum IAQ sensor reading. The high ref-
erence (20 mA output) must be configured to the maximum
IAQ sensor reading.
The IAQ sensor can be configured to either low or high
priority. The priority value can be changed by the user. The
default is low.
Low Priority — When the priority is set to low, the ini-
tial control is to the IAQ set point, but the outside air damper
position will change to its minimum position when the fol-
lowing conditions occur:
• CV units with sensor — when the space temperature is
greater than the occupied cooling set point plus 2° F or
when the space temperature is less than the occupied heat-
ing set point minus 2° F.
• VAV units and CV units with thermostat — when the
supply-air temperature is less than the supply-air tempera-
ture set point minus 8° F or when the supply-air tempera-
ture is greater than the supply air temperature set point
plus 5° F for 4 minutes.
• When the outdoor air quality is greater than the outdoor
air quality set point (ppm)
High Priority — When the priority is set to high, the IAQ
set point controls the outside air damper exclusively, with
no regard to comfort conditioning.
Table 3 — Smoke Control Modes
DEVICE PRESSURIZATION SMOKE PURGE EVACUATION FIRE SHUTDOWN
Economizer 100% 100% 100% 0%
Indoor Fan/VFD ON ON OFF OFF
Power Exhaust (all outputs) OFF ON ON OFF
Heat Stages OFF OFF OFF OFF
HIR ON ON OFF OFF
LEGEND
HIR — Heat Interlock Relay
VFD — Variable Frequency Drive
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