Carrier 50LJ User Manual download pdf (Page 17)

TBI

EQUIP GND

EQUIP — Equipment

GND — Ground

LEGEND

NEC — National Electrical Code

TB — Terminal Block

Fig. 13 — Field Power Wiring Connections

CONTROL WIRING — Install a Carrier-approved acces

sory thermostat assembly according to the installation

instructions shipped with the accessory. Locate thermostat

assembly on a solid wall in the conditioned space to sense

average temperature (where airflow is stable and thermostat

is not in direct line of supply-air duct). Route thermostat

cable or equivalent leads of no. 18 AWG (American Wire

Gage) colored wire from subbase terminals to 24-v terminal

strip (PI). The terminal strip is located on the constant

volume control board on units with no economizer and on

the economizer board on units with the economizer option

(see Fig. 14).

The total wire length between the unit and the thermostat

and the return wire from the thermostat to the unit should

not exceed the following limits: 50 ft of 18 AWG, 80 ft of

16 AWG or 125 ft of 14 AWG. See Fig. 15 for field wiring

connections between the thermostat and the unit 24-v ter

minal block.

There are no required 115-v field wiring connections, there

fore, no provisions have been made in the unit for running

115-v wiring. If any of the field-installed options requiring

115-v connections are desired, the unit must be modified in

the field for 115-v wiring.

Options requiring 24-v or 115-v control wiring are listed

below.

Building Pressurization or Smoke Purge Mode — Refer to

Building Pressurization Mode section and Smoke Purge Mode

section on page 24 for additional information. See Fig. 16

and unit wiring label for wiring details.

1. Firestat or smoke detector (field-supplied switch 1).

Remove factory-installed jumper wire and wire a field-

supplied firestat or smoke deteetor between terminals

2 and 3 on terminal block 2 (TB2) in the unit eontrol

box (see Fig. 14 for the location of TB2 in the control

box).

2. Switch to supply 24-v power to the economizer motor

during building pressurization or smoke purge (field-

supplied switch 5). Wire a normally-open switch

between terminal 3 on TB2 and terminal T1 in the econ

omizer motor.

3. Switch to open economizer outdoor air damper during

building pressurization or smoke purge (field-supplied

switch 6). Wire a field-supplied switch between termi

nals 8 and 9 on the economizer motor (in the top of

economizer motor). When this switch is manually opened,

it will drive the outside air damper fully open.

115-V Connections:

1. Building pressurization switch (field-supplied switch 2).

— Wire a field-supplied switeh between terminal 4 on

TB2 and the Cl connection on the evaporator-fan con

tactor coil (IFCl on unit label diagram).

2. Smoke purge switch (field-supplied switch 4). — Wire

a field-supplied switch between terminal 4 on TB2 (in

the unit control box) and the Cl conneetion on the power

exhaust eontactor coil (PECl on unit label diagram).

3. Switch to isolate evaporator-fan motor from power

exhaust motor during building pressurization or smoke

purge (field-supplied switch 3). — Wire a field-

supplied switch in series with the wire from the Cl

eonnection on the IFCl to the red wire on the econo

mizer damper motor end switch (EDMS on unit label

diagram).

Convenience Outlet

115-V Connection: Convenience outlet can be mounted on

panel containing control circuit breakers CB3 and 4. (See

Fig. 14.) Remove sheet metal cover that conceals 2%

lVi6 in. hole and install outlet in hole. Wire between

terminals 4 and 5 on TB2 in the unit control box (see

Fig. 17). The convenience outlet should be ground fault

protected. Convenience outlet is to be used only when the

unit is not operating.

24-V Connections:

1 2 ... 12 13 14 15 16 17 18 19 20 21 22 ... 37 38

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Carrier 50LJ User Manual Page 17

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