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Table 84 — Indoor Air Quality Configuration
Table 85 — Dehumidification Configuration
Vent Reheat Set Point Select (
D.V.CF) — This configuration
determines how the vent reheat set point is selected.
• D.V.CF = 0 — Reheat follows an offset subtracted from
return air temperature (D.V.RA).
• D.V.CF = 1 — Reheat follows a dehumidification heat
set point (D.V.HT).
Vent Reheat RAT Offset (
D.V.RA) — Set point offset used
only during the vent mode. The air will be reheated to return-
air temperature less this offset.
Vent Reheat Set Point
(D.V.HT) — Set point used only dur-
ing the vent mode. The air will be reheated to this set point.
Dehumidify Cool Set Point (
D.C.SP) — This is the dehu-
midification cooling set point.
Dehumidity RH Set Point (
D.RH.S) — This is the dehumidi-
fication relative humidity trip point.
OPERATION — Dehumidification and reheat can only occur
if the unit is equipped with either staged gas or hydronic heat.
Dehumidification without reheat can be done on any unit but
Configuration
DEHU
D.SEL must be set to 2.
If the machine’s control type is a TSTAT type (Configura-
tion
UNIT
C.TYP=3 or 4) and the discrete input selection
for the sensor is not configured (D.SEN not equal to 2),
dehumidification will be disabled.
If the machine’s control type is a TSTAT type (Configura-
tion
UNIT
C.TYP=3 or 4) and the economizer is able to
provide cooling, a dehumidification mode may be called out,
but the control will not request mechanical cooling.
If a 2-stage control type is selected (Configuration
UNIT
C.TYP = 4 or 6), then the economizer, if active, locks out
mechanical cooling during the Dehumidification mode.
NOTE: Configuring Configuration
DEHU
D.SEN to 2
will enable the CEM board along with the sensor selected for
control.
NOTE: If Configuration
DEHU
D.SEL = 1 or 2, then
staged gas control will be automatically enabled (Configura-
tion
HEAT
HT.CF will be set to 3).
If a tempering, unoccupied or “mechanical cooling locked
out” HVAC mode is present, dehumidification will be disabled.
An HVAC Off, Vent or Cool mode must be in effect to launch
either a Reheat or Dehumidification mode.
If an associated sensor responsible for dehumidification
fails, dehumidification will not be attempted (SPRH, RARH).
Initiating a Reheat or Dehumidification Mode
— To call out
a Reheat mode in the Vent or the Off HVAC mode, or to call
out a Dehumidification mode in a Cool HVAC mode, one of
the following conditions must be true:
• The space is occupied and the humidity is greater than
the relative humidity trip point (D.RH.S).
• The space is occupied and the discrete humidity input is
closed.
Dehumidification and Reheat Control
— If a dehumidifica-
tion mode is initiated, the rooftop will attempt to lower
humidity as follows:
• Economizer Cooling — The economizer, if allowed to
perform free cooling, will have its control point (Run
Status
VIEW
EC.C.P) set to Configuration
DEHU
D.C.SP. If Configuration
DEHU
D.EC.D is dis-
abled, the economizer will always be disabled during
dehumidification.
• Cooling — For all cooling control types: A High Cool
HVAC mode will be requested internally to the control to
ITEM EXPANSION RANGE UNITS CCN POINT DEFAULT
DCV.C DCV ECONOMIZER SETPOINTS
EC.MN Economizer Min.Position 0 - 100 % ECONOMIN 5
IAQ.M IAQ Demand Vent Min.Pos. 0 - 100 % IAQMINP 0
AQ.CF AIR QUALITY CONFIGS
IQ.A.C IAQ Analog Sensor Config 0 - 4 IAQANCFG 0
IQ.A.F IAQ 4-20 ma Fan Config 0 - 2 IAQANFAN 0
IQ.I.C IAQ Discrete Input Config 0 - 2 IAQINCFG 0
IQ.I.F IAQ Disc.In. Fan Config 0 - 2 IAQINFAN 0
OQ.A.C OAQ 4-20ma Sensor Config 0 - 2 OAQANCFG 0
AQ.SP AIR QUALITY SETPOINTS
IQ.O.P IAQ Econo Override Pos. 0 - 100 % IAQOVPOS 100
DAQ.L Diff.Air Quality LoLimit 0 - 1000 DAQ_LOW 100
DAQ.H Diff. Air Quality HiLimit 100 - 2000 DAQ_HIGH 700
D.F.OF DAQ PPM Fan Off Setpoint 0 - 2000 DAQFNOFF 200
D.F.ON DAQ PPM Fan On Setpoint 0 - 2000 DAQFNON 400
IAQ.R Diff. AQ Responsiveness -5 - 5 IAQREACT 0
OAQ.L OAQ Lockout Value 0 - 2000 OAQLOCK 0
OAQ.U User Determined OAQ 0 - 5000 OAQ_USER 400
AQ.S.R AIR QUALITY SENSOR RANGE
IQ.R.L IAQ Low Reference 0 - 5000 IAQREFL 0
IQ.R.H IAQ High Reference 0 - 5000 IAQREFH 2000
OQ.R.L OAQ Low Reference 0 - 5000 OAQREFL 0
OQ.R.H OAQ High Reference 0 - 5000 OAQREFH 2000
IAQ.P IAQ PRE-OCCUPIED PURGE
IQ.PG IAQ Purge Yes/No IAQPURGE No
IQ.P.T IAQ Purge Duration 5 - 60 min IAQPTIME 15
IQ.P.L IAQ Purge LoTemp Min Pos 0 - 100 % IAQPLTMP 10
IQ.P.H IAQ Purge HiTemp Min Pos 0 - 100 % IAQPHTMP 35
IQ.L.O IAQ Purge OAT Lockout 35 - 70 dF IAQPNTLO 50
ITEM EXPANSION RANGE UNITS CCN POINT DEFAULT
DEHU DEHUMIDIFICATION CONFIG.
D.SEL Dehumidification Config 0-2 DHSELECT 0
D.SEN Dehumidification Sensor 1-2 DHSENSOR 1
D.EC.D Econ disable in DH mode? Yes/No DHECDISA Yes
D.V.CF Vent Reheat Setpt Select 0-1 DHVHTCFG 0
D.V.RA Vent Reheat RAT offset 0-8 ^F DHVRAOFF 0
D.V.HT Vent Reheat Setpoint 55-95 dF DHVHT_SP 70
D.C.SP Dehumidify Cool Setpoint 40-55 dF DHCOOLSP 45
D.RH.S Dehumidify RH Setpoint 10-90 % DHRELHSP 55