86
When the outdoor air cfm sensor is enabled, the Economizer
Min.Position (Configuration
IAQ
DCV.C
EC.MN) and
the IAQ Demand Vent Min.Pos (Configuration
IAQ
DCV.C
IAQ.M) will no longer be used. During vent periods,
the control will modulate the damper to maintain the outdoor
air intake quantity between O.C.MX and O.C.MN. The indoor
air quality algorithm will vary the cfm between these two
values depending on Configuration
IAQ
AQ.SP
DAQ.L
and the Configuration
IAQ
AQ.SP
DAQ.H set points
and upon the relationship between the IAQ and the outdoor air
quality (OAQ).
The economizer’s OA CFM Minimum Position Deadband
(O.C.DB) is the deadband range around the outdoor cfm
control point at where the damper control will stop, indicating
the control point has been reached. See the Economizer section
for more information.
Humidification — The N Series ComfortLink controls
can control a field-supplied and installed humidifier device.
The ComfortLink controls provide two types of humidification
control: A discrete stage control (via a relay contact) and a pro-
portional control type (communicating to a LEN actuator). The
discrete stage control is used to control a single-stage humidifi-
er, (typically a spray pump). The proportional control type is
typically used to control a proportional steam valve serving a
steam grid humidifier.
The ComfortLink controls must be equipped with a controls
expansion module and an accessory space or return air relative
humidity sensor.
If a humidifier using a proportional steam valve is selected,
the Carrier actuator (Carrier Part No. HF23BJ050) must be
adapted to the humidifier manufacturer’s steam valve. Contact
Belimo Aircontrols for information on actuator linkage adapter
packages required to mount the actuator on the specific brand
and type of steam valve mounted by the humidifier
manufacturer.
The actuator address must be programmed into the Com-
fortLink unit’s humidifier actuator serial number variables.
SETTING UP THE SYSTEM — These humidity configura-
tion are located in the local displays under Configuration
HUMD. See Table 58. Related points are shown in Table 59.
Humidifier Control Configuration (
HM.CF) — The humidi-
fier control can be set to the following configurations:
• HM.CF = 0 — No humidity control.
• HM.CF = 1 — Discrete control based on space relative
humidity.
• HM.CF = 2 — Discrete control based on return air rela-
tive humidity.
• HM.CF = 3 — Analog control based on space relative
humidity.
• HM.CF = 4 — Analog control based on return air rela-
tive humidity.
Humidity Control Set Point (
HM.SP) — The humidity con-
trol set point has a range of 0 to 100%.
Humidifier PID Run Rate (
HM.TM) — This is the PID run
time rate.
Humidifier Proportional Gain (
HM.P) — This configuration
is the PID Proportional Gain.
Humidifier Integral Gain (
HM.I) — This configuration is the
PID Integral Gain.
Humidifier Derivative Gain (
HM.D) — This configuration is
the PID Derivative Gain.
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 rel-
ative humidity. If the supply fan has been ON for 30 seconds
and the space is occupied, 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 N Series control system has its own
unique serial number. The rooftop control uses this serial
number to communicate with the actuator. The actuator serial
number is located on a two-part sticker affixed to the side of the
actuator housing. Remove one of the actuator’s serial number
labels 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 additional 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 through a calibration at the factory. Field-installed actuators
may be calibrated 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 operation 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.
To Next Page
Loading...
