Carrier 42C Installation And Start-up Instructions Manual

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Carrier 42C Installation And Start-up Instructions Manual Manual pdf 10 page image

10SUPPLY AIR TEMPERATURE (SAT) SENSOR INSTAL-LATION — On fan coil units with heating or cooling, the SATsensor is factory-installed. The SAT is factory-installed in thefan coil air outlet. No installation is required. The part numberis HH79NZ005.INDOOR AIR QUALITY SENSOR INSTALLATION(Monitor Only) — The indoor air quality (IAQ) sensor acces-sory monitors carbon dioxide levels. This information is usedto monitor IAQ levels. Three types of sensors are provided.The wall sensor can be used to monitor the conditioned airspace. Sensors use infrared technology to measure the levels ofCO2 present in the air. The wall sensor is available with orwithout an LCD readout to display the CO2 level in ppm. SeeFig. 12.Sensor accessory descriptions and part numbers are shownin Table 2. To mount the sensor, refer to the installation instruc-tions shipped with the accessory kit.Table 2 — CO2 Sensor AccessoriesThe CO2 sensors listed in Table 2 are all factory set for arange of 0 to 2000 ppm and a linear voltage output of 0 to10 vdc. Refer to the instructions supplied with the CO2 sensorfor electrical requirements and terminal locations.To accurately monitor the quality of the air in the condi-tioned air space, locate the sensor near a return air grille (ifpresent) so it senses the concentration of CO2 leaving thespace. The sensor should be mounted in a location to avoiddirect breath contact.Do not mount the IAQ sensor in drafty areas such as nearsupply ducts, open windows, fans, or over heat sources. Allowat least 3 ft between the sensor and any corner. Avoid mountingthe sensor where it is influenced by the supply air; the sensorgives inaccurate readings if the supply air is blown directlyonto the sensor or if the supply air does not have a chanceto mix with the room air before it is drawn into the returnair-stream.Indoor Air Quality Sensor Wiring — To wire the sensorsafter they are mounted in the conditioned air space or outdoorlocation, see Fig. 13 and the instructions shipped with the sen-sors. For each sensor, use two 2-conductor 18 AWG twisted-pair cables (unshielded) to connect the separate isolated 24 vacpower source to the sensor and to connect the sensor to the con-trol board terminals. To connect the sensor to the control board,identify the positive (0-10 VDC) and ground (SIG COM) ter-minals on the sensor. Connect the 1-10 VDC terminal to termi-nal IAQ and connect the SIG COM terminal to terminal GND.HUMIDITY SENSOR (Wall-Mounted) INSTALLA-TION — The accessory space humidity sensor is installed onan interior wall to measure the relative humidity of the air with-in the occupied space. See Fig. 14.The use of a standard 2- x 4-in. electrical box to accommo-date the wiring is recommended for installation. The sensor canbe mounted directly on the wall, if acceptable by local codes.If the sensor is installed directly on a wall surface, install thehumidity sensor using 2 screws and 2 hollow wall anchors(field-supplied); do not overtighten screws. See Fig. 8.The sensor must be mounted vertically on the wall. TheCarrier logo should be oriented correctly when the sensor isproperly mounted.DO NOT mount the sensor in drafty areas such as near heat-ing or air-conditioning ducts, open windows, fans, or over heatsources such as baseboard heaters, radiators, or wall-mountedlight dimmers. Sensors mounted in those areas will produceinaccurate readings.Avoid corner locations. Allow at least 4 ft between the sen-sor and any corner. Airflow near corners tends to be reduced,resulting in erratic sensor readings.Sensor should be vertically mounted approximately 5 ft upfrom the floor, beside the space temperature sensor.For distances up to 500 feet, use a 3-conductor, 18 or20 AWG cable. A CCN communication cable can be used,although the shield is not required. The shield must be removedfrom the sensor end of the cable if this cable is used. SeeFig. 15 for wiring details.The power for the sensor is provided by the control board.The board provides 24 vdc for the sensor. No additional powersource is required.To wire the sensor, perform the following:1. At the sensor, remove 4-in. of jacket from the cable. Strip1/4-in. of insulation from each conductor. Route the cablethrough the wire clearance opening in the center of thesensor.2. Connect the RED wire to the sensor screw terminalmarked (+).3. Install one lead from the resistor (supplied with the sen-sor) and the WHITE wire, into the sensor screw terminalmarked (–). After tightening the screw terminal, test theconnection by pulling gently on the resistor lead.4. Connect the remaining lead from the resistor to theBLACK wire and secure using a closed end type crimpconnector or wire nut.5. Using electrical tape, insulate any exposed resistor lead toprevent shorting.6. At the control box, remove the jacket from the cable androute the RED conductor over to the left side of the con-trol board. Route the remaining conductors to the rightside of the control board.7. Strip 1/4-in. of insulation from each conductor and equipeach with a 1/4-in. female quick connect terminal.8. Connect the RED wire to terminal 24VDC on the controlboard.NOTE: The 24VDC terminal is used for RH sensorwiring only.9. Connect the BLACK wire to terminal GND on the con-trol board.10. Connect the WHITE/CLEAR wire to terminal RH on thecontrol board.11. Connect shield to ground (if shielded wire is used).Connect the Outputs — Wire the fan coil controller’soutputs (fan, staged heat, valves) as shown in the applicabletypical wiring diagrams in Fig. 2 and 3. Please refer to fan coilunit schematic for full wiring details.CO 2 SENSORACCESSORYPART NUMBERSDESCRIPTION33ZCSENCO2 Wall Mount Sensor (with display)33ZCT55CO2Wall Mount Sensor with33ZCT55SPT space temperaturesensor (no display)33ZCT56CO2Wall Mount Sensor with33ZCT56SPT space temperaturesensor and set point adjustment (nodisplay)Do NOT clean or touch the sensing element with chemicalsolvents; they can permanently damage the sensor.