Carrier 48TCA04---A12 Service And Maintenance Instructions

39PremierLink 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 HH57AC077) --The enthalpy control (HH57AC077) 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 (HH57AC078) isrequired for differential enthalpy control. See below.)Locate the enthalpy control in the economizer hood.Locate two GRA leads in the factory harness and connectthese leads to enthalpy control sensors 2 and 3. See Fig.48. Connect the enthalpy control power input terminals toeconomizer actuator power leads RED (connect to TR)and BLK (connect to TR1).67LCTBECON32EnthalpySwitchGRAGRAFactory Wiring HarnessC08218Fig. 48 -- Enthalpy Switch (HH57AC077) ConnectionsThe outdoor enthalpy changeover setpoint is set at theenthalpy controller.The enthalpy control receives the outdoor air enthalpyfrom the outdoor air enthalpy sensor and provides a drycontact switch input to the PremierLink controller. Aclosed contact indicates that outside air is preferred to thereturn air. An open contact indicates that the economizershould remain at minimum position.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 (HH57AC078) in the return--air duct. Thereturn air sensor is wired to the enthalpy controller(HH57AC077). See Fig. 49.LEDA B CDTR TR1SOSR231++BRNREDGRAY/ORNGRAY/REDWIRE HARNESSIN UNITBLKREDS+(RETURN AIRENTHALPYSENSOR)S+(OUTDOORAIRENTHALPYSENSOR)ENTHALPY CONTROLLERNOTES:1. Remove factory-installed jumper across SR and + before connectingwires from return air sensor.2. Switches shown in high outdoor air enthalpy state. Terminals 2 and 3close on low outdoor air enthalpy relative to indoor air enthalpy.3. Remove sensor mounted on back of control and locate in outside air-stream.C06019Fig. 49 -- 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. At the enthalpy control remove the factory--installedresistor from the (SR) and (+) terminals.3. Connect the field--supplied RED wire to (+) spadeconnector on the return air enthalpy sensor and the(SR+) terminal on the enthalpy controller. Connectthe BLK wire to (S) spade connector on the return airenthalpy sensor and the (SR) terminal on the enthalpycontroller.NOTE: The enthalpy control must be set to the “D”setting for differential enthalpy control to work properly.The enthalpy control receives the indoor and returnenthalpy from the outdoor and return air enthalpy sensorsand provides a dry contact switch input to thePremierLink controller. A closed contact indicates thatoutside air is preferred to the return air. An open contactindicates that the economizer should remain at minimumposition.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 electrical48TC