Carrier 39L Series Installation, Operation, And Start-up Instructions

Also see for 39L Series: Installation, Start-Up and Service Instructions

Carrier 39L Series Installation, Operation, And Start-up Instructions Manual pdf 3 page image

Mount the remote control box as follows:1. Loosen and remove the 4 nuts securing the control panelin the control box.2. Remove the control panel from the box; set the panel andnuts aside for reassembly later.3. Mount the control box to the Unistrutt support using field-supplied fasteners.4. Locate, mark, and drill pilot holes on the top of the boxfor each of the following:• Motor starter wiring• Actuator and sensor wires to fan section junction box• Supply power wires (ac)• Valve wiring or tubing (water valves, field-suppliedsensors, or other devices)5. Expand the pilot holes as required. Recommended sizesare as follows:• Motor starter wiring — 3 ⁄4 in. (5 wires)• Actuator and sensor wires to fan section junctionbox — 3⁄4 in. to 1 in. (number of wires and hole di-ameter determined by application)• Supply power wires (ac) — 1⁄2 in. or 3 ⁄4 in.• Valve wiring or tubing — size as requiredFan section panels are provided with pilot holes that canbe drilled or punched to accomodate an electrical conduitfor the remote control box wiring. Where possible, installthe conduit in a panel that will not be removed, such as thedischarge panel. See Fig. 4.REMOTE CONTROL BOX CONDENSATE PREVEN-TION — When the remote control box is installed, precau-tions must be taken to prevent condensation from forminginside the junction box mounted in the unit’s supply fan sec-tion. Standard installation practice is to mount the remotecontrol box adjacent to the air handling unit and then to en-close the Class II wiring in flexible conduit between the con-trol box and the junction box in the fan section.The sheet metal housing of the control box is not airtight,therefore warm, moist air can migrate through the flexibleconduit to the junction box in the fan section. Condensatecan form inside the junction box and possibly on the termi-nal lugs.To prevent moist air from migrating through the conduit,seal the control wires inside the conduit at the remote con-trol box enclosure. See Fig. 4. Use a nonconductive, non-hardening sealant. Permagum (manufactured by SchneeMorehead) or sealing compound, thumb grade (manufac-tured by Calgon), are acceptable materials.Make Electrical Connections — 39L and 39NX unitshave internal control wiring for the operation of the PIC sec-tion and its control devices. The control system requires adedicated 120 vac or 230 vac (50 or 60 Hz) power circuitcapable of providing a minimum of 10 amps (but not greaterthan 20 amps) to the control box. The actual number of con-trols on one power source depends on the installation andpower circuit requirements. Do not run PIC power wiring inthe same conduit as sensor wiring or control wiring of field-installed devices.IMPORTANT: To ease installation, control wiring islocated on the service side of the unit with electricalconnectors provided at all unit separation points. If aunit is separated into pieces for installation, rejoin allconnectors in their original alpha-numeric sequence uponreassembly. Connectors for vertical fan sections thatare shipped out of the normal operating position mustalso be joined at final assembly.For units with an integral PIC section, all unit factory con-trol wiring is internal. Only a small number of wires must befield-installed. All internal wiring consists of plenum wireswhich enter the rear of the control box through sealed fit-tings. Control wiring is 18 to 20 gage, 2-conductor twistedpair.The electrical power disconnect and fan motor starter arefield-supplied and installed. Connections are provided in thecontrol box to wire a field-supplied HOA (HANDS/OFF/AUTOMATIC) switch. If an HOA switch is used, it must befield-installed in the supply and return fan motor starter cir-cuit. The factory-wired high-pressure switch (variable air vol-ume only) and low-temperature thermostat options are en-ergized when the supply fan circuit is powered.See Fig. 5-7 for control box component arrangements andFig. 8 for fan motor wiring. PIC input and output points arelisted in Table 1. Consult the wiring diagram located in thecontrol box or Fig. 9-12 for further details.Power is present in the PIC control box in the motorstarter circuit even when the dedicated power to the PICcontrol box is off.The supply and return fan starter circuits are independentfrom each other. Either circuit and its related control boxinterface can have 24 vac, 120 vac, or 240 vac power.All options that require a factory-installed transformerare fused with 3.2 amp fuses on the secondary of eachtransformer.When the control box is shipped separately for remote mount-ing, all unit wiring terminates in a junction box located inthe fan section. Refer to Fig. 12 for the applicable wiringdiagram and Table 2 for junction box connections.If the unit is provided with a factory-installed smoke con-trol option, refer to the section titled Field-Wiring Connec-tions, Smoke Control Option, page 54.All PIC electrical components are UL (Underwriters’ Labo-ratories) listed. The electronic modules are approved underUL HVAC Equipment Standard 873. PIC units are listed andlabeled by ETL (Engineering Testing Laboratory) to complywith UL Standard 1995 for heating and cooling units, andcomply with NFPA (National Fire Protection Association)Standard 90A.3