Carrier Infinity 24VNA6 Series Service Manual

Also see for Infinity 24VNA6: Installation instructions Owner's manual

24VNA6 / 25VNA4: Service ManualManufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.3ELECTRICALAluminum WireWhenever aluminum wire is used in branch circuit wiring with this unit,adhere to the following recommendations.Connections must be made in accordance with the National ElectricalCode (NEC), using connectors approved for aluminum wire. Theconnectors must be UL approved (marked Al/Cu with the UL symbol)for the application and wire size. The wire size selected must have acurrent capacity not less than that of the copper wire specified, and mustnot create a voltage drop between service panel and unit in excess of 2 ofunit rated voltage. To prepare wire before installing connector, allaluminum wire must be “brush-scratched” and coated with a corrosioninhibitor such as Pentrox A. When it is suspected that connection will beexposed to moisture, it is very important to cover entire connectioncompletely to prevent an electrochemical action that will causeconnection to fail very quickly. Do not reduce effective size of wire,such as cutting off strands so that wire will fit a connector. Proper sizeconnectors should be used. Check all factory and field electricalconnections for tightness. This should also be done after unit has reachedoperating temperatures, especially if aluminum conductors are used.ELECTRICAL SYSTEM OVERVIEWThe electrical system consists of four main primary components andsub-systems as listed below and shown in Fig. 1• Terminal Block• Transformer• Compressor and Fan Sub-System• Control Sub-SystemA200232Fig. 1 – ELECTRICAL SYSTEM OVERVIEWTerminal BlockThe terminal block provides the connection point for high voltage fieldpower wiringTransformerIMPORTANT: The 24VAC power (Rc) in the PCM comes from thetransformer in the equipment. The phase of this transformer connectionis not controlled relative to the phase of the power provided by thetransformer in the indoor equipment (Rh). Wiring requirements in thismanual do not connect Rc and Rh together. For any non-standardwiring, care should be taken to make sure that Rc and Rh are notconnected together. Doing so may result in destroying one or both of thetransformers in this and the indoor equipment.The transformer converts line voltage power to low voltage powerrequired by the control system. The transformer also provides isolationbetween the line voltage and low voltage systems.Compressor / Fan Sub-SystemThe compressor / fan subsystem consists of the following components:• Variable speed compressor• Variable speed fan• Variable Frequency Drive (VFD) sub-system for driving thecompressor and fanThe VFD sub-system consists of several components that are shownconceptually in Fig. 2 with detailed wiring shown in Fig. 3. Thefunction of each component is described in further detail in the followingsection.WARNING!ELECTRICAL SHOCK HAZARDFailure to follow this warning could result in personal injury or death.Exercise extreme caution when working on any electrical components.Shut off all power to system prior to troubleshooting. Sometroubleshooting techniques require power to remain on. In theseinstances, exercise extreme caution to avoid danger of electrical shock.ONLY TRAINED SERVICE PERSONNEL SHOULD PERFORMELECTRICAL TROUBLESHOOTING.CAUTION!UNIT OPERATION AND SAFETY HAZARDFailure to follow this caution may result in equipment damage orimproper operation.Aluminum wire may be used in the branch circuit (such as the circuitbetween the main and unit disconnect), but only copper wire may beused between the unit disconnect and the unit.CAUTION!Equipment Damage HazardFailure to follow this caution may result in equipment damage orimproper operation.Do not connect the equipment 24VAC supply (Rc) to the indoorequipment 24VAC supply (Rh).TERMINALBLOCKTRANSFORMERCOMPRESSOR &FAN SUB-SYSTEMCONTROLSUB-SYSTEMLine VoltageField Wiring(Power)Low VoltageField Wiring(Communication/ Control)