Carrier 50TCQA04 Installation Instructions Manual

Also see for WeatherMaker 50TCQA07: Installation instructions Installation instructions Service and maintenance instructions

21Locate the thermostat accessory on a solid wall in theconditioned space to sense average temperature inaccordance with the thermostat installation instructions.If the thermostat contains a logic circuit requiring 24--vpower, use a thermostat cable or equivalent single leads ofdifferent colors with minimum of seven leads. If thethermostat does not require a 24--v source (no “C”connection required), use a thermostat cable or equivalentwith minimum of six leads. Check the thermostatinstallation instructions for additional features whichmight require additional conductors in the cable.For wire runs up to 50 ft. (15 m), use no. 18 AWG(American Wire Gage) insulated wire [35_C (95_F)minimum]. For 50 to 75 ft. (15 to 23 m), use no. 16 AWGinsulated wire [35_C (95_F) minimum]. For over 75 ft.(23 m), use no. 14 AWG insulated wire [35_C (95_F)minimum]. All wire sizes larger than no. 18 AWG cannotbe directly connected to the thermostat and will require ajunction box and splice at the thermostat.Unit Without Thru--Base Connection Kit —Pass the thermostat control wires through the holeprovided in the corner post; then feed the wires throughthe raceway built into the corner post to the control box.Pull the wires over to the terminal strip on the upper--leftcorner of the Central Terminal Board. See Fig. 30.NOTE: If thru--the--bottom connections accessory isused, refer to the accessory installation instructions forinformation on routing power and control wiring.RACEWAYHOLE IN END PANEL (HIDDEN)C08027Fig. 30 -- Field Control Wiring RacewayHeat Anticipator Settings —Set heat anticipator settings at 0.14 amp for the first stageand 0.14 amp for second--stage heating, when available.Central Terminal BoardThe Central Terminal Board (CTB) is a pass throughconnection point. The CTB provides the capability to addfactory--installed options and field--installed accessories tothe units by cutting jumper wires without having to changeor reroute wires through the structure of the unit. The CTBdoes not provide any microprocessor control; it is simply abasic multifunction wiring terminal configuration.Commercial Defrost ControlThe Commercial Defrost Control Board (DFB)coordinates thermostat demands for supply fan control, 1or 2 stage cooling, 2 stage heating, emergency heating anddefrost control with unit operating sequences. The DFBalso provides an indoor fan off delay feature (userselectable). See Fig. 31 for board arrangement.DIPSwitchesSpeed-UpJumpersC09275Fig. 31 -- Defrost Control Board ArrangementThe DFB is located in the 50TCQ unit’s main control box(see Fig. 32 on page 22). All connections are factory--madethrough harnesses to the unit’s CTB, to IFC (belt--drivemotor) or to ECM (direct--drive motor), reversing valvesolenoids and to defrost thermostats. Refer to Table 5 (onpage 22) for details of DFB Inputs and Outputs.Reversing valve control — The DFB has two outputs forunit reversing valve control. Operation of the reversingvalves is based on internal logic; this application does notuse an “O” or “B” signal to determine reversing valveposition. Reversing valves are energized during thecooling stages and the defrost cycle and de--energizedduring heating cycles. Once energized at the start of acooling stage, the reversing valve will remain energizeduntil the next heating cycle demand is received. Oncede--energized at the start of a Heating cycle, the reversingvalves will remain de--energized until the next coolingstage is initiated.Compressor control — The DFB receives inputsindicating Stage 1 Cooling, Stage 2 Cooling and Stage 1Heating from the space thermostat or unit control system(PremierLinkt controller or RTU Open controller); itgenerates commands to start compressors with or withoutreversing valve operation to produce Stage 1 Cooling (onecompressor runs), Stage 2 Cooling (both compressors run)or Stage 1 Heating (both compressors run).