Bryant 657A Installation, Start-Up, And Operating Instructions Manual Download Page 15

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3. ROUTING CONTROL POWER WIRES - STD NON-

ECM UNITS (24 v) -Form a drip-loop with the thermostat
leads before routing them into the unit. Route the thermostat
leads through grommeted hole provided in unit (see Fig. 21)
into unit control power splice box. Connect thermostat leads
to unit control power leads as shown in Fig. 23.

4. ROUTING CONTROL POWER WIRES - ECM UNITS

(24 v) - Remove knockout in the duct panel (see Fig. 21).
Remove the rubber grommet from the installer’s packet
(included with unit) and install it in the knockout opening.
Route thermostat wires through grommet providing a drip
loop at the panel. Connect low-voltage leads to the thermo-
stat as shown in Fig. 23.
The Easy Select interface board is located in the return-air
section and is attached to the duct panel. The Easy Select
interface board is factory wired to the motor and factory
default selections are preset.

5. The unit transformer supplies 24-v power for complete

system including accessory electrical heater. Transformer is
factory wired for 230-v operation. If supply voltage is 208
v, rewire transformer primary as described in the Special
Procedures for 208-v Operation section.

NOTE:

Do not use any type of power-stealing thermostat. Unit

control problems may result.

Use no. 18 American Wire Gage (AWG) color-coded, insulated
(35 C minimum) wires to make the control voltage connections
between the thermostat and the unit. If the thermostat is located
more than 100 ft. from the unit (as measured along the control
voltage wires), use no. 16 AWG color-coded, insulated (35 C
minimum) wires.

SPECIAL PROCEDURES FOR 208-V OPERATION

WARNING:

Make sure that the power supply to the unit

is switched OFF and lockout tag installed before making
any wiring changes. Electrical shock can cause serious
injury or death.

1. Disconnect the orange transformer-primary lead from the

contactor. See unit wiring label

2. Remove the wire nut from the terminal on the end of the red

transformer-primary lead.

3. Save the wire nut.

4. Connect the red lead to the contactor terminal from which

the orange lead was disconnected.

5. Using the wire nut removed from the red lead, insulate the

loose terminal on the orange lead.

6. Wrap the wire nut with electrical tape so that the metal

terminal cannot be seen.

NOTE:

Indoor blower motor speeds may need to be changed for

208-v operation. Refer to Indoor Airflow and Airflow Adjustment
Section.

PRE-START-UP

WARNING:

Failure to observe the following warnings

could result in serious personal injury:
1. Follow recognized safety practices and wear protective

goggles when checking or servicing refrigerant system.

2. Do not operate compressor or provide any electric

power to unit unless compressor terminal cover is in
place and secured.

3. Do not remove compressor terminal cover until all

electrical sources are disconnected.

4. Relieve and recover all refrigerant from system before

touching or disturbing anything inside terminal box if
refrigerant leak is suspected around compressor termi-
nals.

5. Never attempt to repair soldered connection while

refrigerant system is under pressure.

6. Do not use torch to remove any component. System

contains oil and refrigerant under pressure. To remove
a component, wear protective goggles and proceed as
follows:
a. Shut off electrical power to unit.
b. Relieve and reclaim all refrigerant from system using

both high- and low-pressure ports.

c. Cut component connecting tubing with tubing cutter

and remove component from unit.

d. Carefully unsweat remaining tubing stubs when

necessary. Oil can ignite when exposed to torch
flame.

Proceed as follows to inspect and prepare the unit for initial
startup:

1. Remove access panel.

2. Read and follow instructions on all WARNING, CAU-

TION, and INFORMATION labels attached to, or shipped
with, unit.

3. Make the following inspections:

a. Inspect for shipping and handling damages such as

broken lines, loose parts, disconnected wires, etc.