Carrier 48EJ, EW, EK, EY024-048 installation instructions Ð Make Electrical Connections

When a VAV unit with a space temperature sensor is ac- cessed via a computer, the following additional features are available:

·ability to initiate timed override from T-55 sensors

·temperature compensated start to calculate early start time before occupancy

·provide space temperature reset to reset the supply air set point upward when the temperature falls below the occu- pied cooling set point

An electronic expansion board may be ®eld-installed to provide the following features:

·fan status

·®lter status

·®eld-applied status

·demand limiting

·IAQ Sensor

·OAQ Sensor

·alarm light

·®re unit shutdown

·®re pressurization

·®re evacuation

·®re smoke purge

When the unit is connected to the CCN (Carrier Comfort Network), the following expansion board features can be utilized:

·CCN IAQ (indoor air quality) participation

·CCN OAQ (outdoor air quality) participation

·CCN demand limit participation

·modulated power exhaust override

·ability to use multiple space temperature sensors (mul- tiples of 4 and 9 only) to average space temperature (DAV only)

A ®eld-supplied T-55 space temperature sensor can be added to monitor room temperature and provide unoccupied over- ride capability (1 hour).

When the unit is equipped with a ®eld-supplied space tem- perature sensor and a remote contact closure (remote start/ stop) the occupied default set points will monitor unit op- eration. The occupied default set points are 55 F (supply air) cooling and 68 F (return air temperature) heating. See Fig. 14 for remote start/stop wiring.

NOTE: For units without a space temperature sensor and which have not had the base unit control board accessed via soft- ware to set an occupancy schedule, the remote start/stop clo- sure will allow the unit to operate in the pre-con®gured oc- cupied default set points of 55 F (supply-air temperature) cooling and 68 F (return-air temperature) heating. Without an occupancy schedule, the unit will control to the unoccu- pied default set points of 90 F (return air) cooling and 55 F (return air) heating.

Features with Network Applications Ð The base control board provides, as standard, a connection for use with a Carrier Comfort System and can also be integrated into a Carrier Comfort Network. When the unit is accessed via a PC equipped with ComfortWorks™, Building Supervisor, or Service Tool software or LID-2B accessory, the following features can be accessed:

·on-board timeclock can be programmed

·occupancy schedules can be programmed

·unit set points can be changed

·alarms can be monitored

This access is available on the base control board via a RJ-11 phone jack or a 3-wire connection to the communi- cation bus. See Fig. 16. The internal timeclock has a 10-hour minimum back-up time to provide for unit power off for ser- vicing unit or during unexpected power outages. For com- plete Carrier Comfort System (CCS) or Carrier Comfort Network (CCN) features and bene®ts, refer to the product literature.

Step 8 Ð Make Electrical Connections

POWER WIRING Ð Units are factory wired for the voltage shown on the unit nameplate.

When installing units, provide a disconnect per NEC (National Electrical Code) of adequate size (MOCP [maxi- mum overcurrent protection] of unit is on the informative plate). All ®eld wiring must comply with NEC and all local codes. Size wire based on MCA (minimum circuit amps) on the unit informative plate. See Fig. 17 for power wiring con- nections to the unit power terminal block and equipment ground.

The main power terminal block is suitable for use with aluminum or copper wire. See Fig. 17. Units have circuit breakers for compressors, fan motors, and control circuit. If required by local codes, provide an additional disconnect switch. Whenever external electrical sources are used, unit must be electrically grounded in accordance with local codes, or in absence of local codes, with NEC, ANSI C1-latest year.

All ®eld wiring must comply with NEC and local code requirements.

FIELD POWER SUPPLY Ð Unit is factory wired for volt- age shown on unit nameplate. See Table 4 for electrical data.

Field wiring can be brought into the unit from bottom (through basepan and roof curb) or through side of unit (cor- ner post next to control box).

A 31¤2-in. NPT coupling for ®eld power wiring and a 3¤4-in. NPT coupling for 24-v control wiring are provided in basepan. In the side post, there are two 21¤2-in. (024-034) or 3-in. (038-048) knockouts for the ®eld power wiring. See Fig. 3-6. If control wiring is to be brought in through the side of unit, a 7¤8-in. diameter hole is provided in the con- denser side post next to the control box.

If disconnect box is mounted to corner post, be careful not to drill any screws into the condenser coil.

Routing Through Bottom of Unit Ð If wiring is brought in through bottom of unit, use ®eld-supplied watertight conduit to run power wiring from basepan out through bottom 31¤2-in. hole to the disconnect box and back into unit to the main control box.

Use strain relief going into control box through 21¤2-in. diameter hole provided. After wires are in unit control box, connect to power terminal block (see Power Wiring section above).

Low-voltage wiring must be run in watertight conduit from the basepan to control box and through 7¤8-in. diameter hole provided in bottom of unit control box. Field-supplied strain relief must be used going into the box. After wiring is in control box, make connections to proper terminals on ter- minal blocks (see Field Control Wiring section on page 21).

Install conduit connector in unit basepan as shown in Fig. 3-6. Route power and ground lines through connector to terminal connections in unit control box as shown on unit wiring diagram and Fig. 17.

Routing Through Side of Unit Ð Route power wiring in ®eld- supplied watertight conduit into unit through 21¤2-in. hole. See Fig. 17.

Use ®eld-supplied strain relief going into control box through 21¤2-in. diameter hole provided. After wires are in unit con- trol box, connect to power terminal block (see Power Wiring section on this page).

Bring low-voltage control wiring through factory-drilled 7¤8-in. diameter hole in condenser side post. Use strain relief going into 7¤8-in. diameter hole in bottom of unit control box.

After wiring is in control box, make connection to proper terminals on terminal blocks (see Field Control Wiring sec- tion on page 21).

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