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It is also necessary to configure how the fan operates when
using the IAQ discrete input.
IAQ Discrete Fan Config (Configuration
IQ.I.F) — This is used to configure the operation of the
fan during an IAQ demand condition. It has the following
configurations:
• IQ.I.F = 0 (No Fan Start) — IAQ demand will never
override normal indoor fan operation during occupied or
unoccupied period and turn it on.
• IQ.I.F = 1 (Fan On If Occupied) — IAQ demand will
override normal indoor fan operation and turn it on (if
off) only during the occupied period (CV operation with
automatic fan).
• IQ.I.F = 2 (Fan On Occupied/Unoccupied) — IAQ
demand will always override normal indoor fan
operation and turn it on (if off) during both the occupied
and unoccupied period.
OAQ 4-20 mA Sensor Config (Configuration
AQ.CF
OQ.A.C) — This is used to configure the type of
outdoor sensor that will be used for OAQ levels. It has the fol-
lowing configuration options:
• OQ.A.C = 0 (No Sensor) — No sensor will be used and
the internal software reference setting will be used.
• OQ.A.C = 1 (OAQ Sensor with DAQ) — An outdoor
CO
sensor will be used.
2
• OQ.A.C = 2 (4 to 20 mA Sensor without DAQ).
IAQ Econo Override Pos (Configuration
IQ.O.P) — This configuration is the position that the econo-
mizer goes to when override is in effect.
Diff. Air Quality Lo Limit (Configuration
DAQ.L) — This is the differential CO
control of the dampers will be initiated.
Diff. Air Quality Hi Limit (Configuration
DAQ.H) — This is the differential CO
control of the dampers will be at maximum and the dampers
will be at the Configuration
DAQ ppm Fan Off Setpoint (Configuration
AQ.SP
D.F.OF) — This is the CO
indoor fan will be turned off.
DAQ
ppm
Fan
On
IAQ
AQ.SP
D.F.ON) — This is the CO
the indoor fan will be turned on.
Diff. IAQ Responsiveness (Configuration
IAQ.R) — This is the configuration that is used to select the
IAQ response curves as shown in Fig. 14.
OAQ Lockout Value (Configuration
OAQ.L) — This is the maximum OAQ level above which de-
mand ventilation will be disabled.
User Determined OAQ (Configuration
OAQ.U) — If an OAQ sensor is unavailable, the user can
manually set the OAQ reading.
IAQ Low Reference (Configuration
IQ.R.L) — This is the reference that will be used with a
non-Carrier IAQ sensor that may have a different characteristic
curve. It represents the CO
level at 4 mA.
2
IAQ High Reference (Configuration
IQ.R.H) — This is the reference that will be used with a
non-Carrier IAQ sensor that may have a different characteristic
curve. It represents the CO
level at 20 mA.
2
OAQ Low Reference (Configuration
OQ.R.L) — This is the reference that will be used with a
non-Carrier OAQ sensor that may have a different characteris-
tic curve. It represents the CO
OAQ High Reference (Configuration
OQ.R.H) — This is the reference that will be used with a non-
Carrier OAQ sensor that may have a different characteristic
curve. It represents the CO
level at 20 mA.
2
IAQ
AQ.CF
IAQ
IAQ
AQ.SP
IAQ
AQ.SP
level at which IAQ
2
IAQ
AQ.SP
level at which IAQ
2
IAQ
DCV.C
EC.MN.
level at which the
2
Setpoint
(Configuration
level at which
2
IAQ
AQ.SP
IAQ
AQ.SP
IAQ
AQ.SP
IAQ
AQ.S.R
IAQ
AQ.S.R
IAQ
AQ.S.R
level at 4 mA.
2
IAQ
AQ.S.R
PRE-OCCUPANCY PURGE — The control has the option
for a pre-occupancy purge to refresh the air in the space prior to
occupancy.
This feature is enabled by setting Configuration
IAQ.P
IQ.PG to Yes.
The IAQ purge will operate under the following conditions:
• IQ.PG is enabled
• the unit is in the unoccupied state
• Current Time is valid
• Next Occupied Time is valid
• time is within two hours of the next occupied period
• time is within the purge duration (Configuration
IAQ
IAQ.P
If all of the above conditions are met, the following logic is
used:
If OAT IQ.L.O and OAT OCSP and economizer is
available then purge will be enabled and the economizer will
be commanded to 100%.
If OAT < IQ.L.O then the economizer will be positioned to
the IAQ Purge LO Temp Min Pos (Configuration
IAQ
IAQ.P
If neither of the above are true then the dampers will be
positioned to the IAQ Purge HI Temp Min Pos (Configuration
IAQ
IAQ.P
If this mode is enabled the indoor fan and heat interlock
relay (VAV) will be energized.
IAQ Purge (Configuration
This is used to enable IAQ pre-occupancy purge.
IAQ
Purge
IQ.P.T) — This is the maximum amount of time that a purge
can occur.
IAQ Purge Lo Temp Min Pos (Configuration
IAQ.P
IQ.P.L) — This is used to configure a low limit for
damper position to be used during the purge mode.
IAQ Purge Hi Temp Min Pos (Configuration
IAQ
IAQ.P
IQ.P.H) — This is used to configure a maximum po-
sition for the dampers to be used during the purge cycle.
IAQ Purge OAT Lockout Temp (Configuration
IAQ.P
IQ.L.O) — Nighttime lockout temperature below
which the purge cycle will be disabled.
Dehumidification and Reheat —
cation function will override comfort condition setpoints
based on dry bulb temperature and deliver cooler air to the
space in order to satisfy a humidity setpoint at the space or
return air humidity sensor. The Reheat function will energize a
suitable heating system concurrent with dehumidification
sequence should the dehumidification operation result in
excessive cooling of the space condition.
The dehumidification sequence requires the installation of a
space or return air humidity sensor or a discrete switch input.
An ECB option is required to accommodate an RH (relative
humidity) sensor connection. A CEM (option or accessory) is
required to accomodate an RH switch. Reheat is possible when
multiple-step staged gas control option or hydronic heat field-
installed coil is installed. Reheat is also possible using a heat
reclaim coil (field-supplied and installed) or a DX (direct ex-
pansion) reheat coil.
Dehumidification and reheat control are allowed during
Cooling and Vent modes in the Occupied period.
On constant volume units using thermostat inputs (C.TYP =
3 or 4), the discrete switch input must be used as the dehumidi-
fication control input. The commercial Thermidistat™ device
is the recommended accessory device.
SETTING UP THE SYSTEM — The settings for dehumidi-
fication can be found at the local display at Configuration
DEHU. See Table 70.
69
IQ.P.T)
IQ.P.L)
IQ.P.H)
IAQ
IAQ.P
Duration
(Configuration
IAQ
IQ.PG) —
IAQ
IAQ.P
IAQ
IAQ
IAQ
The Dehumidifi-
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