Carrier 50TCQA Installation Instructions Manual

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

Contents

29The raceway provides the UL required clearance betweenhigh-- and low--voltage wiring. Pass the control wiresthrough the hole provided in the corner post, then feed thewires thorough the raceway to the RTU--MP. Connect tothe wires to the removable Phoenix connectors and thenreconnect the connectors to the board.Space Temperature (SPT) SensorsA field--supplied Carrier space temperature sensor isrequired with the RTU--MP to monitor space temperature.There are 3 sensors available for this application:S 33ZCT55SPT, space temperature sensor with overridebuttonS 33ZCT56SPT, space temperature sensor with overridebutton and setpoint adjustmentS 33ZCT59SPT, space temperature sensor with LCD(liquid crystal display) screen, override button, andsetpoint adjustmentUse 20 gauge wire to connect the sensor to the controller.The wire is suitable for distances of up to 500 ft. Use athree--conductor shielded cable for the sensor and setpointadjustment connections. If the setpoint adjustment(slidebar) is not required, then an unshielded, 18 or 20gauge, two--conductor, twisted pair cable may be used.Connect T--55 -- See Fig. 31 for typical T--55 internalconnections. Connect the T--55 SEN terminals toRTU--MP J20--1 and J20--2. See Fig. 50.SENSENJ20-1J20-2C08460Fig. 50 -- RTU--MP T--55 Sensor ConnectionsConnect T--56 -- See Fig. 33 for T--56 internalconnections. Install a jumper between SEN and SETterminals as illustrated. Connect T--56 terminals toRTU--MP J20--1, J20--2 and J20--3 per Fig. 51.SEN J20-1J20-2SENSETJumperJ20-3SETC08461Fig. 51 -- RTU--MP T--56 Sensor ConnectionsConnect T--59 -- The T--59 space sensor requires aseparate, isolated power supply of 24 VAC. See Fig. 51for internal connections at the T--59. Connect the SENterminal (BLU) to RTU--MP J20--1. Connect the COMterminal (BRN) to J20--2. Connect the SET terminal (STOor BLK) to J20--3.OR SET SENOPB COM- PWR+BLU (SPT)BLK (STO)24 VACSENSORWIRINGPOWERWIRINGBRN (COM)NOTE: Must use a separate isolated transformer.C07132Fig. 52 -- Space Temperature Sensor Typical Wiring(33ZCT59SPT)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 “Return AirEnthalpy Sensor” 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. SeeFig. 36. Connect the enthalpy control power inputterminals to economizer actuator power leads RED(connect to TR) and BLK (connect to TR1).The 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 (HH57AC078) in the return--air duct. Thereturn air sensor is wired to the enthalpy controller(HH57AC077). See Fig. 37.To 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 air50TCQA