Carrier 50EK, 50EJ, 50EW, 50EY Make Electrical Connections, Field Power Wiring Connections

For units running Version 1.0 of the unit control software, network access software is required to enable occupied heat- ing. For units running Version 2.0 of the unit control soft- ware, occupied heating is enabled or disabled by the posi- tion of DIP switch no. 5.

Additional features may be provided with electronic ac- cess to Unit Control Board. These features are:

·control board diagnostics

·compressor time guard override (power up, minimum off and on times)

·compressor lockout during low supply-air temperature

·electronic expansion board features (if installed)

·®eld test capability

·control of the economizer damper and indoor fan to op- tion unoccupied free cooling

·365 day timeclock with backup (supports minute, hour, day, month, and year)

·holiday table containing up to 18 holiday schedules

·occupancy control with 8 periods for unit operation

·support a set of display, maintenance, con®guration, serv- ice, and set point data tables for interface with Building Supervisor, Comfort Works, or Service Tool

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

·ability to use multiple space temperature sensors to aver- age space temperature

·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

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

·®re unit shutdown

·®re pressurization

·®re evacuation

·®re smoke purge

·modulated power exhaust override

A ®eld-supplied space temperature sensor can be added to provide the following:

·T-57 sensor will monitor room temperature

·T-55 sensor will monitor room temperature and provide unoccupied override 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 (space temperature) heating (if electric heat is installed). See Fig. 11 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 (if electric heat is installed).

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 Comfort Works, Building Supervisor, or Service Tool software, 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. 12. The timeclock has a 10-hour mini- mum back-up time to provide for unit power off for servic- ing unit or during unexpected power outages. For complete Carrier Comfort System (CCS) or Carrier Comfort Network (CCN) features and bene®ts, refer to the product literature.

Step 7 Ð Make Electrical Connections

POWER WIRING Ð Units are factory wired for the voltage shown on the unit nameplate. The main terminal block is suitable for use with aluminum or copper wires and is sized for single-point electric heat.

When installing units, provide a disconnect per NEC (Na- tional Electrical Code) of adequate size (MOCP [maximum 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. 13 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. 13. Units have circuit breakers for compressors, fan motors, and control circuit. If required by local codes, provide an additional disconnect, per NEC and local codes requirements, of adequate size (Table 4). 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 (American National Standards Institute) 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 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).

		LEGEND
EQUIP	Ð	Equipment
GND	Ð Ground
NEC	Ð	National Electrical Code
TB	Ð	Terminal Block

NOTE: Maximum wire size for TB1 is 500 MCM.

Fig. 13 Ð Field Power Wiring Connections

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