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Table 60 —
Dehumidification Configuration
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 when the Humidi-MiZer function is
initiated and the unit enters a Reheat mode. This occurs when
the relative humidity is above set point with no cooling de
-
mand. The air will be reheated to return-air temperature less
this offset.
Vent Reheat Set Point (D.V.HT)
Set point used only when the Humidi-MiZer function is initiat
-
ed and the unit enters a Reheat Mode. This occurs when the
relative humidity is above set point with no cooling demand.
When
D.V.CF
= 0, the supply air will be reheated to
D.V.HT
minus
D.V.RA
. When
D.V.CF
= 1, the supply air will be re
-
heated to
D.V.HT
.
Dehumidify Cool Set Point (D.C.SP)
This is the Humidi-MiZer cooling set point used to determine
the temperature the air will be cooled to prior to it being reheated
to the desired supply-air temperature. This set point is used
during the Humidi-MiZer Dehumidification and Reheat modes
of operation.
Dehumidify RH Set Point (D.RH.S)
This is the Humidi-MiZer relative humidity trip point.
Dehumidify RH Deadband (DH.DB)
This is the dehumidification relative humidity sensor's deadband.
Dehum Discrete Timeguard (DH.TG)
This is the dehumidification discrete switch's timeguard.
Humidi-MiZer Adjust Rate (HZ.RT)
This is the rate (seconds) at which corrections are made in the
position of the modulating valves (
C.EXV
and
B.EXV
) to
maintain supply air set point.
Humidi-MiZer Proportional Gain (HZ.PG)
This is the proportional gain used in calculating the required
valve position change for supply air temperature control. It is
essentially the percentage of total reheat capacity adjustment
that will be made per degree Fahrenheit of supply air tempera
-
ture error.
OPERATION
Mode Qualifications
An HVAC: Off, Vent or Cool mode must be in effect to launch
a Humidi-MiZer mode.
Sensor Failure
If an associated sensor responsible for controlling Humidi-MiZer
fails, dehumidification will not be attempted (
SPRH
,
RARH
).
Initiating a Humidi-MiZer Reheat or Dehumidification Mode
To call out a Reheat mode in the “Vent” or “Off” HVAC mode,
or to call out a Dehumidification mode in a Cool HVAC mode,
one of the following 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.
Ending a Humidi-MiZer Reheat or Dehumidification Mode
When either the humidity sensor falls below relative humidity
sensor's dead band % (
Configuration
DEHU
DH.DB
) or
below the set point (
Configuration
DEHU
D.RH.S
),
or the
discrete input reads “LOW”, and discrete switch time guard ex
-
pires (
Configuration
DEHU
DH.TG
), the Humidi-MiZer
mode will end.
Relevant Outputs
The Humidi-MiZer 3-way valve (reheat valve) commanded
output can be found in
Outputs
COOL
RHV
.
The Humidi-MiZer Condenser Modulating Valve (Condenser
EXV) position output can be found in
Outputs
COOL
C.EXV
. The condenser position will be provided as
percent open.
HUMIDI-MIZER MODES
Dehumidification Mode (Subcooling)
This mode will be engaged to satisfy part-load type conditions
when there is a space call for cooling and dehumidification. Al
-
though the temperature may have dropped and decreased the sen
-
sible load in the space, the outdoor and/or space humidity levels
may have risen. A typical scenario might be when the outside air
is 85°F and 70 to 80% relative humidity (RH). Desired SHR for
equipment in this scenario is typically from 0.4 to 0.7. The Humi
-
di-MiZer unit will initiate Dehumidification mode when the space
temperature and humidity are both above the temperature and hu
-
midity set points, and attempt to meet both set point requirements.
Once the humidity requirement is met, the unit can continue to op
-
erate in normal cooling mode to meet any remaining sensible ca
-
pacity load. Alternatively, if the sensible load is met and humidity
levels remain high, the unit can switch to Hot Gas Reheat mode to
provide neutral, dehumidified air.
Reheat Mode
This mode is used when dehumidification is required without a
need for cooling, such as when the outside air is at a neutral
temperature, but high humidity exists. This situation requires
the equipment to operate at a low SHR of 0.0 to 0.2. With no
cooling requirement and a call for dehumidification, the N Se
-
ries Humidi-MiZer adaptive dehumidification system will cy
-
cle on enough compressors to meet the latent load requirement,
while simultaneously adjusting refrigerant flow to the Humidi-
MiZer coil to reheat the air to the desired neutral air set point.
ITEM
EXPANSION
RANGE
UNITS
CCN POINT
DEFAULT
DEHU
DEHUMIDIFICATION CONFIG.
D.SEL
Dehumidification Config
0-5
DHSELECT
0
D.SEN
Dehumidification Sensor
1-3
DHSENSOR
1
D.EC.D
Econ disable in DH mode?
No/Yes
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
55-75
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
DH.DB
Dehumidify RH Deadband
1-30
%
DHSENSDB
5
DH.TG
Dehum Discrete Timeguard
10-90
sec
DHDISCTG
30
HZ.RT
Humidi-MiZer Adjust Rate
5-120
HMZRRATE
30
HZ.PG
Humidi-MiZer Prop. Gain
0-10
HMZR_PG
0.8
Содержание WeatherExpert 48N2
Страница 135: ...135 Fig 18 48 50N Typical Power Schematic Nominal 075 Ton Unit Shown ...
Страница 136: ...136 Fig 19 48 50N Typical Power Schematic Nominal Ton 90 150 Units Shown ...
Страница 137: ...137 Fig 20 48 50N Main Base Board Input Output Connections ...
Страница 138: ...138 Fig 21 48 50N RXB EXB CEM Input Output Connections a48 9307 ...
Страница 139: ...139 Fig 22 48 50N EXV SCB Input Output Connections a48 9308 ...
Страница 140: ...140 Fig 23 48N Typical Modulating Gas Heat Unit Control Wiring ...
Страница 141: ...141 Fig 24 50N Typical Electric Heat Unit Control Wiring ...
Страница 144: ...144 Fig 27 48N Typical Gas Heat Section Wiring Nominal Ton 120 to 150 Units ...
Страница 145: ...145 Fig 28 48 50N Typical Power Component Control Wiring 460 v ...
Страница 146: ...146 Fig 29 48 50N Component Control Wiring 575 v Nominal Ton 075 to 150 Units ...
Страница 147: ...147 Fig 30 48 50N Component Arrangement Power Box ...
Страница 148: ...148 Fig 31 48 50N Component Arrangement Control Box ...
Страница 168: ...168 Fig 47 Sensor and Ignition Position Fig 48 Combustion Blower Details SENSOR DETAILS IGNITION DETAILS ...
Страница 240: ...240 APPENDIX D VFD INFORMATION CONT Fig G VFD Bypass Wiring Diagram WHEN USED ...