Carrier 48PG03-16 Controls, Start-Up, Operation, Service And Troubleshooting Instructions page 69

COMP
CLOSED VALVE
OPEN VALVE
Units with multiple circuits can operate with additional staging of
the cooling and dehumidification capacity. When there is only
cooling demand, based on a space temperature sensor or
thermostat, one or more circuits will operate in normal cooling
mode. When there is only dehumidification demand, based on a
space humidity sensor or switch, all circuits will operate in
reheat2 mode. When there is both cooling demand and
dehumidification demand, all circuits will operate in either
reheat1 or reheat2 mode, with the portion of reheat1 circuits
determined from the cooling demand.
Outdoor fan control for
includes a Motormaster® variable-speed control of some or all
outdoor fans, depending on unit model size. The Motormaster
control automatically adjusts the outdoor fan speed to maintain
approximately 80_ to 100_F condenser temperature for circuit A
at all outdoor ambient temperatures. Some model sizes have
additional on/off staging of some outdoor fans. This staging is
controlled by both outdoor temperature and condenser coil
temperature.
Compressor staging control for Humid-MiZer units requires that
circuit A always operate when either circuits B or C are on. This
applies to normal operation, service test, and for control alarm
responses. This operation difference is required due to the fact
that the Motormaster outdoor fan control senses circuit A only.
Setting Up the System
The system requires installation and configuration of either a
space relative humidity sensor or a relative humidity switch input.
See the Third Party Control section for wiring diagram figure and
additional information.
Space Humidity Switch (Configuration→UNIT→RH.SW)
Set to 1 for use of a normally open switch, or 2 for normally
closed switch. The switch is wired to field connection terminal
board terminals labeled HUMDISTAT.
RH2.x
COND COIL
OUTDOOR AIR
Fig. 11 --- Hot Gas Reheat Mode (Reheat2) — Humidi- -MiZert System
Humidi-MiZer system units
RH1.x
HUMIDI-MIZER COIL
CV.x
EVAP COIL
INDOOR ENTERING
AIR
RH Sensor on OAQ Input (Configuration→UNIT→RH.S)
Set to Yes for use of a 4 to 20 mA output RH sensor wired to
field connection terminal board terminals 3 and 4. If using an RH
sensor, the following configurations also apply:
Space RH Setpoint (Setpoints→RH.SP)
This sets the target % relative humidity.
Space RH Deadband (Setpoints→RH.DB)
This sets the control ± deadband for % relative humidity.
RH Sensor Value at 4ma (Configuration→AIR.Q→H.4M)
This sets the % display for a 4mA input from the relative
humidity sensor.
RH Sensor Value at 20ma (Configuration→AIR.Q→H.20M)
This sets the % display for a 20mA input from the relative
humidity sensor.
Reheat Heat SP Deadband (Setpoints→RH.HB)
If the unit is configured for use of a space temperature sensor
instead of a thermostat (Configuration→UNIT→U.CTL = Yes),
then this configuration applies. This configuration sets the offset
above the heating set point at which a unit in Reheat2 mode will
turn off. This is a protection against over cooling the space and
causing a heat demand.
Other configurations affecting the Humidi-MiZer operation are
located at Configuration→HMZR. See Appendix A.
NOTE: These configurations are dependent on the specific unit
and should not be changed. The configurations are provided in
case a field replacement of a control board occurs and the settings
need to be checked or manually configured.
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METERING
DEVICE
a48-8174
C07005