Carrier WeatherMaker 48TC 04, Руководство по установке

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52
To accurately monitor the quality of the air in the condi-
tioned air space, locate the sensor near a return-air grille (if
present) so it senses the concentration of CO
2
leaving the
space. The sensor should be mounted in a location to avoid di-
rect breath contact.
Do not mount the IAQ sensor in drafty areas such as near
supply ducts, open windows, fans, or over heat sources. Allow
at least 3 ft (0.9 m) between the sensor and any corner. Avoid
mounting the sensor where it is influenced by the supply air;
the sensor gives inaccurate readings if the supply air is blown
directly onto the sensor or if the supply air does not have a
chance to mix with the room air before it is drawn into the re-
turn airstream.
Wiring the Indoor Air Quality Sensor — For each sensor, use
two 2-conductor 18 AWG (American Wire Gage) twisted-pair
cables (unshielded) to connect the separate isolated 24 vac
power source to the sensor and to connect the sensor to the con-
trol board terminals.
To connect the sensor to the control, identify the positive (4
to 20 mA) and ground (SIG COM) terminals on the sensor. See
Fig. 53. Connect the 4-20 mA terminal to RTU Open J4-2 and
connect the SIG COM terminal to RTU Open J4-3. See Fig. 70.
Fig. 70 — RTU Open/Indoor CO
2
Sensor
(33ZCSENCO2) Connections
Outdoor Air Quality Sensor (P/N 33ZCSENCO2 plus
weatherproof enclosure) — The sensor is designed to monitor
carbon dioxide (CO
2
) levels in the outside ventilation air and
interface with the ventilation damper in an HVAC system. The
OAQ sensor is packaged with an outdoor cover. See Fig. 55.
The outdoor air CO
2
sensor must be located in the economizer
outside air hood.
Wiring the Outdoor Air CO
2
Sensor — A dedicated power
supply is required for this sensor. A two-wire cable is required
to wire the dedicated power supply for the sensor. The two
wires should be connected to the power supply and terminals 1
and 2.
To connect the sensor to the control, identify the positive (4
to 20 mA) and ground (SIG COM) terminals on the OAQ sen-
sor. See Fig. 53. Connect the 4 to 20 mA terminal to RTU Open
J4-5. Connect the SIG COM terminal to RTU Open J4-6. See
Fig. 71.
Fig. 71 — RTU Open / Outdoor CO
2
Sensor
(33ZCSENCO2) Connections
Space Relative Humidity Sensor or Humidistat
NOTE: The accessory space relative humidity sensor and
humidistat are not available for single phase (-3 voltage
code) models.
Humidi-MiZer
®
Control Wiring — In units equipped with
the Humidi-MiZer option there are two pink (PNK) wires loose
in the control box used to control the dehumidification function
of the unit. These pink wires are meant to be tied to a space hu-
midistat or thermidistat on an electromechanical unit. On RTU
Open equipped units these pink wires must be connected to
J11-7 and 8 to allow the Open board to operate the dehumidifi-
cation function for the unit. Disconnect the J11 Phoenix style
connector from the board and use the plug screws to secure the
pink wires in pins 7 and 8, reconnect the plug to the board at
J11.
NOTE: The Humidi-MiZer system is a factory-installed
option which is available for 07 models only.
Relative Humidity Sensors (Space or Duct Mounted) — The
accessory space humidity sensor (33ZCSENSRH-01) or duct
humidity sensor (33ZCSENDRH-01) is used to measure the
relative humidity of air within the space or return air duct. The
RH reading is used to control the Humidi-MiZer option of the
rooftop unit. For wiring distances up to 500 ft (152 m), use a
3-conductor, 18 or 20 AWG shielded cable. The shield must be
removed from the sensor end of the cable and grounded at the
unit end. The current loop power for sensor is provided by the
RTU Open controller as 24vdc. Refer to the instructions sup-
plied with the RH sensor for the electrical requirements and
terminal locations. RTU Open configurations must be changed
after adding an RH sensor. See Fig. 72 and 73 for typical RH
sensor wiring.
• J4-1 or J4-4 = 24vdc loop power
• J4-2 or J4-5 = 4-20mA signal input
NOTE: The factory default for dehumidification control is
normally open humidistat.
Fig. 72 — Space Relative Humidity Sensor Typical
Wiring
Humidistat — The accessory humidistat provides the RTU
Open insight to the relative humidity in the space. The humidi-
stat reads the RH level in the space and compares it to its set-
point to operate a dry contact. The humidistat is a dedicated in-
put on the configurable input 9 and tells the RTU Open when
the RH level is HIGH or LOW. The normal condition for hu-
midity is LOW. A normally open humidistat is the factory de-
fault control for the Humidi-MiZer ® option.
S EN
COM
J4-2
J4- 3
IAQ S en s or
24 VAC
S EN
COM
J4-5
J4-6
OAQ S en s or
24 VAC
SW2
1 2 3 4 5 6
ON
Io Vin Gnd
Vo
MOUNTING
HOLES
WIRING
OPENING
Vin - J4-1 or J4-4 24Vdc
Io - J4-2 or J4-5 -20mA output