Carrier 50AJ/AK/AM020 Installation Instructions Manual

Contents

28.For transformer 1 move the black wires connected to termi-nal H2 and connect it to terminal H3.For transformers 2-4, that are used for the 24 volt controlcircuits, connect as follows:1. Remove cap from red (208 v) wire.2. Remove cap from spliced orange (230 v) wire. Discon-nect orange wire from black unit power wire.3. Cap orange wire.4. Splice red wire and black unit power wire. Cap wires.If the unit is equipped with the optional convenience outletconnect the yellow wire to H2 on transformer 5.FIELD CONTROL WIRING — The 50A series units sup-port a large number of different modes of operation as well asfactory-installed options and field-installed accessories thatwill impact the field control wiring. Refer to Fig. 16-25.The control options that the unit can provide are based onthe following parameters:• CV (constant volume), VAV (Variable Air Volume), VVT®(Variable Volume Variable Temperature) or Carrier TEMPsystem.• Standalone with a thermostat (CV) or with a space sensor(CV and VAV)• Network Application with Carrier CCN or other networks• Demand Ventilation with CO2 sensor• Economizer and Economizer with Changeover control• Building and Duct Pressure Control• Fire Shutdown and Smoke Control• Diagnostics and MonitoringFor constant volume applications a thermostat (T-Stat) orspace temperature sensor (SPT) will be required.T-STAT (Conventional Thermostat) — Unit can be con-trolled with a Carrier-approved accessory electro-mechanicalor electronic thermostat that has two stages of cooling, twostages of heating control and an output for indoor fan control. Itmay also include time of day scheduling or use the schedulingroutines built into the ComfortLink™ controls.Install thermostat according to the installation instructionsincluded with accessory thermostat. Locate thermostat assem-bly on a solid interior wall in the conditioned space to sense av-erage temperature.Route thermostat cable or equivalent single leads of coloredwire from subbase terminals through conduit into unit to lowvoltage connection in the main control box, as shown in Fig. 19and 20. For thermostat TB4 connections see Fig. 16.NOTE: For wire runs up to 50 ft, use no. 18 AWG (AmericanWire Gage) insulated wire (35 C minimum). For 50 to 75 ft,use no. 16 AWG insulated wire (35 C minimum). For over75 ft, use no. 14 AWG insulated wire (35 C Minimum). Allwire larger than no. 18 AWG cannot be directly connected atthe thermostat and will require a junction box and splice at thethermostat. Set heat anticipator settings as follows:Settings may be changed slightly to provide a greater degree ofcomfort for a particular installation.SPT (Space Temperature Sensor) — For constant volume ap-plications the ComfortLink controls can also be used with T55and T56 space temperature sensors that use a 10K thermistor.The T56 sensor also has the capability for a ± 5 F temperatureset point offset at the thermostat. For variable air volume appli-cations only the T55 sensor can be used.Install sensor according to the installation instructions in-cluded with accessory sensor. Locate sensor assembly on a sol-id interior wall in the conditioned space to sense average tem-perature.Run wiring to the space sensor as shown in Fig. 17.Note that when the remote sensor is used, the red jumperwires must be connected from TB4 terminal 4 to 5 and TB4terminal 5 to 1.Both the T55 and T56 have a CCN communications port andthis should be wired to the CCN Communications TB3 board. Ifmore than 1 sensor is being used and averaged, sensors must bewired in multiples of 4 or 9 as shown in Fig. 18.T58 Communicating Thermostat — Carrier also has a fullycommunicating thermostat which, if used, will be wired to theCCN communication connections on TB3 as described in theCarrier Comfort Network Interface section below.Carrier Comfort Network Interface — The rooftop units canbe connected to the CCN. The communication bus wiring issupplied and installed in the field. Wiring consists of shielded,3-conductor cable with drain wire. The system elements areconnected to the communication bus in a daisy chain arrange-ment. The positive pin of each system element communicationconnector must be wired to the positive pins of the system ele-ment on either side of it, the negative pins must be wired to thenegative pins, and the signal pins must be wired to signalground pins. Wiring connections for CCN should be made atthe TB3 terminal block using the screw terminals. The TB3board also contains an RJ14 CCN plug that can be used toconnect a Navigator™ display or field service computer. Thereis also another RJ14 LEN connection that is used to downloadsoftware.IMPORTANT: On 208/230-v units, transformers 1-5are wired for 230-v. If 208/230-v unit is to be run with208-v power supply, the transformers must be rewiredas follows:IMPORTANT: BE CERTAIN UNUSED WIRES ARECAPPED. Failure to do so may damage the transformers.SIZE STAGE 1(W1) ONSTAGE 2(W1 & W2) ON020-050 0.24 0.13060 0.36 0.13R Y1 Y2 W1 W2 G C XR Y1 Y2 W1 W2 G C XFIELD SUPPLIED THERMOSTATLIGHTRCT1 T212 43 5678910111213141516TH C SNT56 SPTT55 SPTUNITTB5TB4Fig 16 — Field Control Thermostat WiringFig. 17 — T55 or T56 Wiring