Carrier Weathermaster 48P2030-100 - Dehumidification and Reheat

88
Table 68 — Humidity Configuration
Table 69 — Related Humidity Points
OPERATION
For operation, PID control will be utilized. The process will
run at the rate defined by the Configuration
 HUMD 
H.PID  HM.TM. The first part of humidity control tests the
humidity control configuration and will turn on corresponding
configurations to read space or return air relative humidity. If
the supply fan has been ON for 30 seconds and the space is oc-
cupied, then the humidification is started.
Actuator Control
Control is performed with a generic PID loop where:
Error = HM.SP – humidity sensor value (SP.RH or RA.RH,
depending on configuration).
The PID terms are calculated as follows:
P = K * HM.P * error
I = K * HM.I * error + “I” last time through
D = K * HM.D * (error – error last time through)
Where K = HM.TM/60 to normalize the effect of changing the
run time rate
Relay Output Control
If the humidity sensor reading is greater than the humidity set
point then the humidity relay (Outputs
 GEN.O  HUM.R) is
closed. The relay will open when the humidity is 2% less than
the humidity set point.
CONFIGURING THE HUMIDIFIER ACTUATOR
Every actuator used in the P Series control system has its own
unique serial number. The rooftop control uses this serial num-
ber to communicate with the actuator. The actuator serial num-
ber is located on a two-part sticker affixed to the side of the ac-
tuator housing. Remove one of the actuator’s serial number la-
bels and paste it onto the actuator serial number records label
located inside the left-hand access panel at the unit’s control
panel. Four individual numbers make up this serial number.
Program the serial number of the actuator in its Humidifier Ac-
tuator Configurations group, ACT.C (SN.1, SN.2, SN.3, SN.4).
NOTE: The serial numbers for all actuators can be found inside
the control doors of the unit as well as on the actuator itself. If an
actuator is replaced in the field, it is a good idea to remove the ad-
ditional peel-off serial number sticker on the actuator and cover up
the old one inside the control doors.
Control Angle Alarm (Configuration
 HUMD  ACTC 
C.A.LM)
The humidifier actuator learns what its end stops are though a
calibration at the factory. Field-installed actuators may be cali-
brated in the Service Test mode. When an actuator learns its
end stops through calibration, it determines its control angle.
The actuator will resolve this control angle and express its op-
eration in a percent (%) of this learned range.
If the humidifier actuator has not learned a sufficient control
angle during calibration, the actuator will be unable to control
humidity. For this reason, the humidifier actuator has a config-
urable control angle alarm low limit (C.A.LM). If the control
angle learned through calibration is less than C.A.LM, an alert
will occur and the actuator will not function.
NOTE: This configuration does not typically need adjustment. It
is configurable for the small number of jobs which may require a
custom solution or workaround.
Dehumidification and Reheat
The Dehumidification function will override comfort condition
set points based on dry bulb temperature and deliver cooler and
lower moisture content air off of the unit evaporator coil to satis-
fy a humidity set point at the space or return air humidity sensor.
The Reheat function will energize a suitable heating system con-
current with dehumidification sequence in order to raise the unit
leaving air temperature up to the Vent, Cool, or Heat supply air
temperature set point in order to not over-cool the space. The de-
humidification sequence requires the installation of a space or
return air humidity sensor or a discrete switch input. A CEM
(option or accessory) is required to accommodate an RH (rela-
tive humidity) sensor connection. Reheat is possible when multi-
ple-step staged gas or modulating gas control option or hydronic
heat (option or field-installed coil) is installed. Reheat is also
possible using a heat reclaim coil (field-supplied and installed)
or a hot gas reheat coil (special order, factory-installed). Reheat
is not possible with electric heat.
Dehumidification and reheat control are allowed during Cool-
ing, Heating, and Vent modes in the Occupied period.
On constant volume units using thermostat inputs (C.TYP = 3),
the discrete switch input must be used as the dehumidification
control input. The commercial Thermidistat™ device is the
recommended accessory device.
ITEM EXPANSION RANGE UNITS CCN POINT DEFAULT
HUMD HUMIDITY CONFIGURATION
HM.CF Humidifier Control Cfg. 0 to 4 HUMD_CFG 0
HM.SP Humidifier Setpoint 0 to 100 % HUSP 40
H.PID HUMIDIFIER PID CONFIGS
HM.TM Humidifier PID Run Rate 10 to 120 sec HUMDRATE 30
HM.P Humidifier Prop. Gain 0 to 5 HUMID_PG 1
HM.I Humidifier Integral Gain 0 to 5 HUMID_IG 0.3
HM.D Humidifier Deriv. Gain 0 to 5 HUMID_DG 0.3
ACT.C HUMIDIFIER ACTUATOR CFGS
SN.1 Humd Serial Number 1 0 to 9999 HUMD_SN1 0
SN.2 Humd Serial Number 2 0 to 6 HUMD_SN2 0
SN.3 Humd Serial Number 3 0 to 9999 HUMD_SN3 0
SN.4 Humd Serial Number 4 0 to 254 HUMD_SN4 0
C.A.LM Humd Ctrl Angle Lo Limit 0 to 90 HUMDCALM 85
ITEM EXPANSION UNITS CCN POINT WRITE STATUS
ConfigUNITSENSSRH.S Space Air RH Sensor SPRHSENS
ConfigUNITSENSRRH.S Return Air RH Sensor RARHSENS
InputsREL.HRA.RH Return Air Rel. Humidity % RARH forcible
InputsREL.HSP.RH Space Relative Humidity % SPRH forcible
OutputsACTUHMD.P Humidifier Act.Curr.Pos. % HUMDRPOS
OutputsACTUHMD.C Humidifier Command Pos. % HUMDCPOS
OutputsGEN.OHUM.R Humidifier Relay HUMIDRLY