Carrier 50TCQA Installation Instructions Manual

Also see for 48TC*D: Service and maintenance instructions Installation instructions

Contents

22If the 50TCQ unit has an economizer system andfree--cooling operation is required, a sensor representingReturn Air Temperature must also be connected(field--supplied and installed). This sensor may be a T--55Space Sensor (see Fig. 31) installed in the space or in thereturn duct, or it may be sensor PNO 33ZCSENSAT,installed in the return duct. Connect this sensor to TB1--1and TB1--3 per Fig. 32.Configure the unit for Thermostat Mode — Connect to theCCN bus using a CCN service tool and navigate toPremierLink Configuration screen for Operating Mode.Default setting is Sensor Mode (value 1). Change thevalue to 0 to reconfigure the controller for ThermostatMode.When the PremierLink is configured for ThermostatMode, these functions are not available: Fire Shutdown(FSD), Remote Occupied (RMTOCC), Compressor Safety(CMPSAFE), Supply Fan Status (SFS), and Filter PressureSwitch (FILTER).Economizer controls —Outdoor Air Enthalpy Control (PNO 33CSENTHSW) --The enthalpy control (33CSENTHSW) is available as afield--installed accessory to be used with the EconoMi$er2damper system. The outdoor air enthalpy sensor is part ofthe enthalpy control. (The separate field--installedaccessory return air enthalpy sensor (33CSENTSEN) isrequired for differential enthalpy control. See Fig. 36.)Locate the enthalpy control in the economizer next to theActuator Motor. Locate two GRA leads in the factoryharness and connect the gray lead labeled “ESL” to theterminal labeled “LOW”. See Fig. 36. Connect theenthalpy control power input terminals to economizeractuator power leads RED (connect to 24V) and BLK(connect to GND).7ESLCTBECONLOWGND24VEnthalpySwitchGRABLKREDFactory Wiring HarnessECONOMOTORC09026Fig. 36 -- Enthalpy Switch (33CSENTHSW) ConnectionsThe outdoor enthalpy changeover setpoint is set at theenthalpy controller.Differential Enthalpy Control — Differential enthalpycontrol is provided by sensing and comparing the outsideair and return air enthalpy conditions. Install the outdoorair enthalpy control as described above. Add and install areturn air enthalpy sensor.Return Air Enthalpy Sensor — Mount the return--airenthalpy sensor (33CSENTSEN) in the return--air sectionof the economizer. The return air sensor is wired to theenthalpy controller (33CSENTHSW). See Fig. 37.ESLLOWGND24VGRABLKRED ECONOMOTOR– 4-20Main+ VDCOut– 4-20 MainOut+ 24-36VDC InC09027Fig. 37 -- Outside and Return Air Enthalpy SensorWiringTo wire the return air enthalpy sensor, perform thefollowing:1. Use a 2--conductor, 18 or 20 AWG, twisted pair cableto connect the return air enthalpy sensor to the enthal-py controller.2. Connect the field--supplied RED wire to (+) spadeconnector on the return air enthalpy sensor and the(+) terminal on the enthalpy controller. Connect theBLK wire to (--) spade connector on the return air en-thalpy sensor and the (--) terminal on the enthalpycontroller.Indoor Air Quality (CO2 sensor) — The indoor air qualitysensor accessory monitors space carbon dioxide (CO2 )levels. This information is used to monitor IAQ levels.Several types of sensors are available, for wall mountingin the space or in return duct, with and without LCDdisplay, and in combination with space temperaturesensors. Sensors use infrared technology to measure thelevels of CO2 present in the space air.The CO2 sensors are all factory set for a range of 0 to2000 ppm and a linear mA output of 4 to 20. Refer to theinstructions supplied with the CO2 sensor for electricalrequirements and terminal locations. See Fig. 38 fortypical CO2 sensor wiring schematic.50TCQA